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Hindawi Publishing CorporationJournal of SpectroscopyVolume 2013 Article ID 217268 13 pageshttpdxdoiorg1011552013217268

Research ArticleXPS Study of Mechanically Activated YBa2Cu3O6+120575 andNdBa2Cu3O6+120575

A V Fetisov1 G A Kozhina1 S Kh Estemirova1 V B Fetisov2 V Ya Mitrofanov1

S A Uporov1 and L B Vedmidrsquo1

1 Institute of Metallurgy Ural Branch of the Russian Academy of Sciences 101 Amundsen Street Ekaterinburg 620016 Russia2 Ural State Academy of Agriculture Karl Liebknecht Street 42 Ekaterinburg 620075 Russia

Correspondence should be addressed to G A Kozhina gakozhinayandexru

Received 27 February 2013 Accepted 30 March 2013

Academic Editor Kong-Thon Tsen

Copyright copy 2013 A V Fetisov et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Oxides RBa2Cu3O6+120575

(R=Y Nd) subjected to mechanical activation in AGO-2mill have been studied by X-ray photoelectron spec-troscopy (XPS) thermal analysis and magnetometry It has been shown that mechanoactivation accelerates chemical degradationunder the impact of H

2O andCO

2in YBa

2Cu3O6+120575

samples Degradation occurs in the standard way Investigation ofmechanicallyactivated NdBa

2Cu3O6+120575

has revealed other results It has been suggested that CO2can diffuse into its structure more freely

than in YBa2Cu3O6+120575

as a result carbonization may proceed directly in the volume of NdBa2Cu3O6+120575

and independently of thehydrolysis process In addition the mechanism of interaction between the oxide and water is not active and not ldquotraditionalrdquo for thehomologous series REBa

2Cu3O6+120575

(where RE = rare earth and Y)mdashthe characteristic ldquocolorrdquo phase (Nd2BaCuO

5) is not formed

during hydrolysis It is known that high-temperature treatment of NdBa2Cu3O6+120575

oxide results in partial substitution of cationsBa by Nd which is accompanied by decrease in the superconducting transition temperature and formation of the impurity phaseBa2Cu3O5+119910

According to our data mechanical activation of the resulting solid solution Nd1+119909

Ba2minus119909

Cu3O6+120575

unexpectedly hasled to the reverse redistribution of cations which has been manifested in the complete disappearance of the impurity phase andincrease in T

119888

1 Introduction

Compounds RBa2Cu3O6+120575

(R=Y and Ln elements) are wellknown as high-temperature superconductors with the tem-perature of the transition to the superconducting state of 90ndash93K [1] The composition with R=Y is a standard materialfor superconducting electronics under development cooledwith liquid nitrogen [2 3] the magnetic field sensor of 120587SQUID type [2] high current cables [4] and other productsBesides this compound has very significant oxygen diffusionparameters and there is an intention to use it as oxygen-ionconductor [5]

It is also known that the replacement of yttrium byneodymium results in the emergence of so-called ldquoanomalouspeak effectrdquo [6] which leads to significant improvementof the superconducting transport properties of the mate-rial An additional advantage of the oxide NdBa

2Cu3O6+120575

(Nd-123) is its higher chemical stability by comparison with

YBa2Cu3O6+120575

(Y-123) [7 8] The disadvantage of Nd-123is ease of substitution of neodymium by barium ions intheir structural positions during high temperature anneal-ing [8ndash10] with the result that the temperature of thetransition to the superconducting state (119879

119888) of the solid

solution Nd1+xBa2minusxCu3O6+120575 appears to be relatively low and

it decreases rapidly with increasing 119909 (maximum 119879119888equal

to 94K was recorded at 119909 = 0 [9] and 119879119888asymp 80 j 60K

were reported for 119909 = 008 j 016 resp [10]) Effect ofsubstitution of barium by neodymium is amplified at highvalues of temperature and oxygen partial pressure [8 9]Simultaneously with the enrichment of the superconductingoxide by neodymium to comply with cation balance in thesystem the impurity phase depleted in this element (egBaCuO

2[9]) is formed

It should be noted that the superconducting propertiesof the solid solution Nd

1+xBa2minusxCu3O6+120575 can be significantlyreduced even when 119909 rarr 0 due to the mutual penetration

2 Journal of Spectroscopy

of Nd and Ba in the structural position of each other whichcan occur during high-temperature annealing in an oxygenenriched atmosphere [9]

It is known [11] that high-intensity mechanical activa-tion processing (hereinafter MA) can significantly modifyphysicochemical properties of various materials At the sametime such researches focused on the change of the functionalproperties of superconducting oxides RBa

2Cu3O6+120575

(R-123)and to our knowledge have not yet been carried out (existingworks like [12] are devoted to mechanical activation ofprecursors) Apparently this is related to the fact that thechemical stability of these oxides to the impact of air atmo-sphere components is not high even in the normal state [1]Besides mechanical treatment leads to substantial increaseand activation of the free surface contacting with the atmo-sphere and during grinding spalling of R-123 particles occursmainly along the basal plane of the crystallites and exposesthe chemically active structural layer BaO [13] Neverthelessin the present study we have attempted to assess how muchthe surface of R-123 actually degrades under MA and justas importantly what is the influence of this effect on thefunctional properties of these superconducting oxides Wehave limited our investigations to compounds with R=Y Ndwhich are promising for applied developments

Thus the objectives of this work were (1) analysis of thechemical composition of the surface of mechanoactivatedR-123 powders (hereinafter MP) and determination of thedegree of its chemical degradation under the influence ofaggressive components of the environment H

2O and CO

2

(2) analysis of the effect of mechanical activation on thefunctional properties of the superconducting material

To fulfill the tasks we used the following methods X-raydiffraction (XRD) thermal analysis magnetometry and X-ray photoelectron spectroscopy (XPS) The latter is a power-ful tool to study the chemical and even phase compositionof the material locallymdashin the thin layer (nearly 10 nm inthickness) of the external boundary This method allowsdetecting impurity phases occurring at the average volumeconcentration outside the sensitivity of X-ray diffraction andalso phases in the amorphous state

2 Experimental Technique

Oxides R-123 were obtained by stepwise annealing a mixtureof barium nitrate Ba(NO

3)2(ldquochemically purerdquo grade) the

corresponding oxide of the rare earth element (RE) and basiccopper carbonate CuCO

3times Cu(OH)

2(ldquoespecially purerdquo

grade) at 798K for 5 h 998K (5 h) and 1213 K (140 h) Theproducts were subjected to oxidative annealing by slow (withfurnace) cooling from the synthesis temperature to 673K andexposed to this temperature in air for 3 hours The oxygencontent of the samples (6 + 120575) according to the oxidativeannealing conditions can be estimated as 690 plusmn 003 [1] Thethus obtained material was ldquoinitial samplerdquo (hereinafter IP)

In the course of our research we also needed to obtainsamples of Nd

2BaCuO

5and Y

2BaCuO

5to determine the

spectral parameters of these compounds as we did not find

relevant and reliable data in the literature They were synthe-sized at 1000∘C for 23 h from previously obtained Nd-123 andY-123 with the addition of necessary amounts of BaCO

3and

Nd2O3(Y2O3) Before the synthesis homogenized mixtures

of reagents were compressed into tabletsMechanical activation of the synthesized oxides Nd-123

and Y-123 was performed in a high energy AGO-2 planetaryball mill (set material Fe) with acceleration of milling bodiesof 60 g The initial powders were dry milled for 05 1 2 and10min The obtained materials were mechanically activatedpowders (hereinafter MP) referred to respectively as N-05N-1 N-2 N-10 (series of Nd-123) and Y-05 Y-2 Y-10 (seriesof Y-123) The particles size was determined using a scanningelectron microscope Carl Zeiss EVO 40 (Germany) andamounted to (3ndash5) sdot 10minus6m while the particles themselveswere agglomerates consisting of stuck together crystalliteswith the size of nearly 03 sdot 10minus6m

X-ray examination of samples was carried out usinga diffractometer Shimadzu XRD-7000 (Japan) The size ofcoherent scattering regions (CSR) was determined by X-raydiffraction analysis using the approximation method [14]Silicon powder was used to determine the instrumentalbroadening of the diffraction lines Selection of the functionfor approximating diffraction peaks was made using theprogram [15]

Thermal studies were carried out using the thermal ana-lyzer Netzsch STA 449C Jupiter (Germany) combined witha mass spectrometer Netzsch QMS 403C Aeolos (Germany)for evolved gas analysis The rates of heating and cooling ofsamples were 10 Kmin

Themagnetization (119898) wasmeasured using a commercialvibrating sample magnetometer Cryogenic CFS-9T-CVTIin the temperature range 42ndash300K The measurements inthe heating mode were performed on samples cooled in amagnetic field (field cooling FC) and in the absence of mag-netic field (zero field cooling ZFC)

XPS study was performed on a OmicronMultiprob spec-trometer (Germany) The test sample (RBa

2Cu3O6+120575

powderand R

2BaCuO

5ceramic tablet where R=Y Nd) was attached

to the sample holder using conductive double-sided adhesivetape and moved into the workspace of the spectrometerCeramic samples were subjected to scribing in ultrahighvacuum before study The source of the exciting radiation forXPSwasMg-anode of X-ray gunwith 170WThe energy scaleof the spectrometer was calibrated by the binding energiesof the peaks Au 4f

72(8400 eV) Ag 3d

52(36829 eV) and

Cu 2p32

(93267 eV) The value of samples surface chargewas determined by the difference between the measuredbinding energy of the C 1s signal due to CndashH groups and thevalue of 2850 eV Wide-scan survey spectra were recordedwith 05 eV energy step and the signal accumulation timeof 1 s at the pass energy (119864PE) of 100 eV High-resolutionspectrum was recorded with 005 eV energy step exposuretime of 75 s (15 scans by 05 s) and 119864PE = 20 eV Theaccuracy of peak position determination in the latter case was01 eV Decomposition of the spectra into components andextraction of the background were performed by the Shirleymethod using the program XPSPeak 41

Journal of Spectroscopy 3

3 Experimental Results

31 Oxides Y2BaCuO

5and Nd

2BaCuO

5

Attestation of Y2BaCuO

5and Nd

2BaCuO

5Oxides by XRD

and XPS Methods X-ray analysis has not shown the presenceof any impurity phases in the synthesized oxides Y

2BaCuO

5

and Nd2BaCuO

5 Syngony space group and lattice param-

eters for Y2BaCuO

5oxide are respectively orthorhombic

Pbnm a = 71304(6) A b = 121761(10) A c = 56571(6) A forNd2BaCuO

5oxide tetragonal P4mbm a = 66950(5) A c =

58188(9) AThe results of XPS study of these oxides are shown in

Figure 1 Decomposition of the obtained electronic spectrawas carried out on the basis of choosing the most appropriatemodel for the phase composition of the surface and themutual coherence between the spectra of different elements(with adjustments taking into account the analyzer trans-mission efficiency and differences in the photoionizationcross-section) The spectrometric data for oxides BaO Y

2O3

Nd2O3 and barium carbonate were taken from [16 33ndash35]

respectivelyLet us discuss some controversial points arising during

decomposition of the spectra As can be seen from Figure 1in the spectra of the sample containing neodymium thereare the intense peaks at 7790 (Ba 3d

52) and 5286 (O 1s)

eV which coincide with the signal from BaO [33] with highaccuracy This can mean that the synthesis of the samplehas not been completed and the unspent furnace chargecomponents have been localized in the surface layer of thematerial (location explains the fact that X-ray analysis unlikeXPS has not revealed the presence of impurity oxides inthe sample) hiding the main compound (Nd

2BaCuO

5) and

making its identification ambiguous To test this hypothesiswe have prepared one more sample Nd

2BaCuO

5at more

high the synthesis temperaturemdash1050∘C It was expected thatif indicated signals belonged to BaO their intensity wouldsignificantly decrease along with increase in intensity of themain compound peaks after the new heat treatment Butnothing like this has happenedmdashthe intensity of all the peaksstayed the sameThat proves that the peaks at 7790 (Ba 3d

52)

and 5286 (O 1s) eV relate directly to the oxide Nd2BaCuO

5

In addition to the main compound there is a bariumcarbonate on the surface of Nd

2BaCuO

5sample that is

confirmed by the peak of corresponding intensity at 2891 eVin the spectrum of C 1s see Figure 1 This presence is appar-ently due to insufficiently complete decomposition of sourceBaCO

3involved in the synthesis (there was not barium

carbonate on the surface of the sample synthesized at 1050∘Chowever there was a similar amount of unidentified bariumcompound with the binding energy of Ba 3d

52electronic

level of 7807 eV)Next we turn our attention to the sample Y

2BaCuO

5 for

which the intensity of the barium oxide peak in O 1s spec-trum according to calculations should be negligible andamount to sim150 of the main compound peak intensityHowever in a given location of the spectrum (more preciselynear 529 eV) there is a clear peak whose intensity is about 14of the intensity of the peak that is near (referred to Y

2BaCuO

5

compound) We suppose that this small peak also belongsto the main compound Indeed O 1s peak of Y

2BaCuO

5at

5313 eV is located near the corresponding peak of the yttriumoxide (see Figure 1) which is explained by the presence of thesame type of YndashO bond in both oxides Meanwhile there isalso a BandashO bond in Y

2BaCuO

5compound which should

be reflected by additional oxygen peak located near the O 1s-peak of barium oxide Note that only one peak was enough todescribe O 1s spectrum of Nd

2BaCuO

5

Quantitative analysis of the elements carried out on thebasis of the decomposition of the spectra has shown a goodagreement with formula composition for both compoundsunder study

32 Oxides YBa2Cu3O6+120575

and NdBa2Cu3O6+120575

321 X-Ray Diffraction Study of Oxides YBa2Cu3O6+120575

andNdBa

2Cu3O6+120575

Theobtained lattice parameters data and thesize of the coherent scattering region are presented in Table 1One can see that the first 1-2 minutes of grinding lead to asignificant decrease in the size of CSR in both superconduc-tors that is refinement of the microstructure With increas-ing milling duration up to 10min further changes of CSR-size practically do not occur However there is a fundamentaldifference in the effect of mechanical activation on the phasecomposition of Y-123 andNd-123 In the initially single-phaseyttrium superconductor with increasingmilling duration theamount of impurity phase (Y

2BaCuO

5) increases continu-

ously whereas in the neodymium superconductor it is viceversamdasha small amount of impurity phase (Ba

2Cu3O5+x) exist-

ing in the initial sample is not observed in all mechanicallyactivated samples This confirms the findings of the highchemical stability of Nd-123 oxide by comparison with itsyttrium homologue

Another interesting point worthy of discussion is the factthat there is no more than one impurity in all the testedsamples (Y-123 and Nd-123) that according to the massbalance should affect the cation stoichiometry in the mainphase of the sample

As for Nd-123 samples deviations from the ideal cationstoichiometry after a long (150 hours) high-temperatureannealing is just a characteristic feature of them [9] Appear-ance of impurity Ba

2Cu3O5+x phase in an amount of 3

indicates that the IP of Nd-123 (sample N-0) is in fact a solidsolution Nd

103Ba197

Cu3O6+120575

Unspent Ba (in amount ofsim3) seems to form under atmospheric moist air the X-rayamorphous phase of Ba(OH)

2sdot nH2O which is easily trans-

formed into BaCO3from the surface due to the presence of

CO2in the air

Y-123 MP which contains a rich by yttrium impurityY2BaCuO

5 to comply with the ion balance should include

the phase not containing this element Since these phaseswere not detected by XRD we have assumed that as a resultof mechanical activation they became X-ray amorphous Infact they were later identified by us with the use of XPS seelater

322 XPS Study of YBa2Cu3O6+120575

Oxide Figure 2 shows thesurvey spectra of the powders YBa

2Cu3O6+120575

under study


Cu 2p

Nd2BaCuO5

Y2BaCuO5

930 940 950 960Binding energy (eV)

(a)

Nd2BaCuO5

Y2BaCuO5

280 282 284 286 288 290Binding energy (eV)

C 1s

(b)

Nd2BaCuO5

BaCO3

Y2BaCuO5

BaO

776 780 784 788 792 796 800 804Binding energy (eV)

Ba 3d

(c)

BaCO3

Y2BaCuO5


Y2O3

Nd2BaCuO5

Nd2O3

O 1s

(d)

Nd2O3

Nd2BaCuO5

116112 120 124 128 132Binding energy (eV)

Nd 4d

(e)

Y 3d

Y2BaCuO5

Y2O3

148 150 152 154 156 158 160 162 164Binding energy (eV)

(f)

Figure 1 XPS spectra of Y2BaCuO

5and Nd

2BaCuO

5oxides The peaks related to the main oxide are marked by bold lines The ordinate

hereinafter is the intensity of the XPS signal in arbitrary units To reduce the figure size the y-axis itself is not shown


Table 1 Phase composition lattice parameters and the size of coherent scattering regions (119871) for YBa2Cu3O6+120575


beforeand after mechanical treatment

Crystallographic parameters Milling duration in AGO-2(1) YBa

2Cu3O6+120575

powders0 s

(sample Y-0)30 s

(sample Y-05)2min

(sample Y-2)10min

(sample Y-10)The main phasemdashorthorhombic SG Pmmm119886 A 38208(3) 38218(3) 38287(10) 38344(10)119887 A 38884(5) 38893(5) 38938(15) 38879(15)119888 A 116809(11) 116793(12) 116739(33) 116663(31)119881 A3 173541(53) 173599(55) 174036(161) 173919(158)Impurity mass mdash sim5 Y

2BaCuO

5sim5 Y

2BaCuO

5sim7 Y

2BaCuO

5

119871 nm 167 57 25 20(2) NdBa

2Cu3O6+120575

powders0 s

(sample N-0)30 s

(sample N-05)2min

(sample N-2)10min

(sample N-10)The main phasemdashorthorhombic SG Pmmm119886 A 38677(1) 38731(3) 38727(12) 38754(12)119887 A 39202(1) 39206(10) 39225(14) 39161(15)119888 A 117612(3) 117622(24) 117630(39) 117661(24)119881 A3 178328(6) 178608(118) 178688(178) 178564(212)Impurity mass sim3 Ba

2Cu3O5+119909

mdash mdash mdash119871 HM 1792 325 229 169


Y-10Cu 2p

Y-2Fe 2pY-05

Y 3d Y-0Ba 4d

Ba 3d

C 1s

O 1s

0

Figure 2 XPS survey spectra of the initial and mechanoactivatedYBa2Cu3O6+120575

samples

Recording such spectra conducted in high sensitivity mode(at high 119864PE) allows to consider the main lines of all elementspresented in the surface layer of the material in amountsgreater than 03 at As could be expected there are peaks ofthe electronic levels of yttrium barium copper and oxygencontained in the composition of the oxide under study TheC 1s peak includes a signal from the carbon contamination ofthe random nature

One can see (Figure 2) that on the surface of MP sam-ples there is no iron (mill headsets material) leading tothe appearance of specific magnetic and superconductingproperties of the material Strongly increased barium peak

(represented as a doublet of Ba 3d52minusBa 3d

32) in the spectra

of activated samples testifies the redistribution of elementsbetween the volume and surface occurs which is usuallythe result of chemical degradation of the surface under theinfluence of an environment In this case it could be a well-established [36] reactions as follows

2YBa2Cu3O65+119909+ 3H2O

997888rarr Y2BaCuO

5+ 3Ba(OH)

2+ 5CuO+ uarr119909O

2

(1)

Ba(OH)2+ CO2997888rarr BaCO

3+H2O (2)

Table 2 summarizes the obtained BaCO3of CP grade cal-

cinated at 700∘C Y2BaCuO

5and taken from the literature of

spectrometric data for the reactants involved in the reactions(1) and (2) for reliable identification of the peaks of thesecompounds in the spectra of the samples under study

High-resolution XPS spectra showing the characteristicelectronic levels of the elements constituting Y-123 samplesare presented in Figure 3

The analysis of the Ba 3d spectra has showed that in addi-tion to barium carbonate (line Ba 3d

52at 7799 eV) there is

the phase Y2BaCuO

5(line Ba 3d

52at sim782 eV) on the surface

of the samplesThe line Ba 3d52

at 7780 eVwhich is observedonly in the IP is directly owned by Y-123 (see Table 2)The Y 3d spectra confirm the presence of Y

2BaCuO

5-phase

on the surface of samples the substancersquos line Y 3d52

at1587 eV is clearly visible in these spectra (see Table 2)Besides the Y 3d spectra reveal the surface contains thefollowing oxides Y

2O3[34] (line Y 3d

52at 1569 eV) Y-123


Ba 3d

Y-10

Y-2

Y-05

Y-0

776 780 784 788 792 796 800Binding energy (eV)

3d523d32

(a)

Binding energy (eV)

Y 3d

Y-10

Y-2

Y-05

Y-0

150 152 154 156 158 160 162 164 166

(b)

Cu 2p

Y-10 Satellite I Satellite II

Y-2

Y-05

Y-0


2p32

2p12

(c)

Figure 3 XPS spectra of YBa2Cu3O6+120575

powders Dark shading the main phase signal light shading Y2BaCuO

5signal

Table 2 The positions of the characteristic XPS lines of barium compounds

Electron orbital BaCO3 Ba(OH)2 Y-123 Y2BaCuO

5

Binding energy eV

Ba 3d52

7799 [16 17]7798lowast

7813 plusmn 01[18 19]

7777 plusmn 01[20ndash23] 7819lowast

Ba 4d52 893lowast 875

[22]

Y 3d52

1560 plusmn 02[21 24 25] 1587lowast

Cu 2p32

9335[21 26] 9356lowast

O 1s5314 plusmn 01[16 17]5314lowast

5312 qB[27]

52845 plusmn 005 qB[20ndash23] (5291 5313)lowast

C 1s28925 plusmn 015 qB

[16 17]2894lowast

lowastOur data

(line Y 3d52

at 1560 eV in the spectrum of IP) and the phaseY2(C2O4)3[37] (line Y 3d

52at 1601 eV) The presence of

Y2BaCuO

5compound in samples is also reflected in the

spectra of Cu 2p a high-energy doublet (main peak at9356 eV) corresponds to it At the same time the low-energyCu 2p-doublet parameters are close to those found in [22] forY-123 the main peak at 9335 eV a satellite at sim943 eV as wellas parameters relating to copper oxide Cu (II) [28] 9336 eVand 9425 eV respectively However from the analysis of thespectra of Ba 3d and Y 3d (see earlier) it can be argued that

the Cu 2p signal from the phase of Y-123 may be only in thespectrum of IP samples

Thus in addition to the main phase the surface of IPcontains the final products of the reactions (1) + (2) and Y

2O3

phase probably sourced by the initial precursor incompletelyconsumed during the synthesis of YBa

2Cu3O6+120575

As a resultof MA treatment the surface of the powder is covered with alayer of yttriumoxide and the products of reactions (1) + (2) toa considerable depth of at least 10 nm (judging by the amountof Y2BaCuO

5phase in the samples determined by XRD)


323 XPS Study of NdBa2Cu3O6+120575

Oxide Figure 4 demon-strates the survey spectra of Nd-123 powders One can seethat as in the case of Y-123 samples the signal representingthe iron was not observed for any intensive milling durationThe feature of Nd-123 samples is rather low intensity of the Ba3d and Ba 4d peaks for powders activated for 05 and 2min(compare Figure 4 with Figure 2 for Y-123 powder) Bariumpeaks has markedly increased (as well as oxygen O 1s peak)only at 10min of activation

Figure 5 shows the high-resolution spectra of the elec-tronic levels of barium (3d and 4d) neodymium (4d) andcopper (2p) in powders with different activation prehistoryIn the barium spectra the high-intensity peaks at 7799 eV(3d52

) and 893 eV (4d52

) are obviously responsible for thecompound BaCO

3 and the low-intensity peaks at 7780 and

876 eV which are observed only in IP samples (dark shadedin Figure 5) correspond to the main phase by analogy withY-123 samples The analysis of Cu 2p spectra has revealed thepresence of copper ions with the electronic structure similarto that in Y-123 or in CuO oxide

However as seen in Figure 5 the state Cu 2p with highbinding energy (9359 plusmn 03 eV) is also present in all Nd-123samples According to our data (see Table 3) this state is nottypical for simple and ternary compounds of copper DuringMA processing its share in Cu 2p spectra changes in strictaccordancewith the high energy components of the Ba 3d andBa 4d spectra light shaded in Figure 5 (at 7817 eV (Ba 3d

53)

and 919 plusmn 03 eV (Ba 4d53

)) which implies that a doubleoxide of barium-copper was on the surface of the samplesWe tend to identify this oxide as Ba

2Cu3O5+x phase which

was detected by X-ray diffraction analysis of IP samples (seeTable 1) Despite the fact that this phase was not found byXRD in samples N-05 N-1 and N-2 it is visible in the XPSspectra due to the effect of spatial localization

According to Figure 5 the surface of the samples alsocontained the oxide Nd

2O3(line Nd 4d

52at 1211 eV) which

under intense grinding at the initial stages was partly trans-formed into Nd

2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)

Based on the analysis of possible superpositions of the spectraof Ba 3d Ba 4d and Cu 2p the low-energy Nd 4d doublet(line Nd 4d

52at 1157 eV) the intensity of which is almost

independent of the MA duration belongs to a double oxideNdCu

119910O15+y+z of undetermined composition The Nd 4d

doublet of themain compound apparently overlaps with oneof the previously noted signals and so it is shown explicitlyin Figure 5

On the intensity ratios of the peaks in Figure 5 one canconstruct a model of the relative position of the phases Nd-123 BaCO

3 and Ba

2Cu3O5+x in the surface layer of the

material (this method has been used eg in [22] to analyzethe relative position of the layers Y-123 and BaCuO

2) To

realize this we use the dependence of the layer thicknessanalyzed by XPS (usually taken as 3 sdot 120582

119898) on the kinetic

energy of the electrons [38] referring to the electrons givingthe corresponding lines in the spectra of Ba 3d and Ba 4d asfollows

120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05

N-0Cu LVVCu 3s C 1sNd 4d

Ba 4d200 400 600 800 1000

Binding energy (eV)0

Figure 4 XPS survey spectra of the initial and mechanoactivatedNdBa

2Cu3O6+120575

samples

where 120582119898is the electron mean free path expressed in mono-

layers 119886 is monolayer thickness in nm 119864119896is kinetic energy

in eV (119864119896= ℎ] minus 119864BE minus 120593) ℎ] = 12536 eV is the energy of

the exciting radiation used inXPS analysis119864BE is the bindingenergy of the electronic level under analysis and120593 is theworkfunction of the spectrometer (346 eV)

According to this relationship the thickness of the layerunder analysis increases monotonically with increasing 119864

119896

in the range 119864119896gt 40 eV As can be seen from Figure 6

increase in the thickness of the layer under analysis canaffect the following volume ratios detectable by XPS phaseIphase III and phase IIphase III and has no influence onthe volume relation phase Iphase II The phase fractionto a first approximation is proportional to the area undercorresponding XPS peak Therefore based on the ratio ofareas of the different lines in the spectra in Figure 5 one canconclude that both barium-containing products of chemicaldecomposition of Nd-123 are located atop of the main oxidethat is correspond to phases I and II in Figure 6 The thick-ness of the degraded layer in N-10 sample is sim10 nm (as theoriginal phase is barely visible through it) and in IP (N-0)sample it is estimated to be 5-6 nm

It should be noted however that such a small thicknessof Ba2Cu3O5+x layer in IP has not prevented this phase to be

recognized by XRD analysis (see Table 1) One can thereforeconclude that IP particles contain in addition a considerableamount of Ba

2Cu3O5+x in the form of individual inclusions

in bulk (as a result of this oxide synthesis features seeSection 1) DuringMA processing material particles crackedand inclusions went outside resulting in the fraction ofBa2Cu3O5+x phase on the surface increased up to a point

(up to 1min inclusive) The subsequent decrease in thisphase (see Figure 5) is apparently due to the fact that anotherprocess also developed on the surface during grindingspending of Ba

2Cu3O5+x involving the original solid solution

Nd1+xBa2minusxCu3O6+120575 to formation of cation-stoichiometric

NdBa2Cu3O6+120575

To prove the occurrence of such interaction


Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0


Satellite I Satellite II

Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)

Figure 5 XPS spectra of NdBa2Cu3O6+120575

powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt

Figure 6 Analysis of the mutual arrangement phases in the surface layer of the material and their volume relations from XPS data


Table 3 Characteristic spectral parameters of different copper compounds

Electron orbital CuO CuCO3 Cu(OH)2 Cu2CO3(OH)2 Nd2BaCuO5

Binding energy eVBa 3d

527790lowast

Nd 4d52

1182lowast

Cu 2p32

9337 plusmn 1[28ndash30]

9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data

later we present the data of magnetic measurements whichindicate that MA treatment results in significant increase inthe temperature of the superconducting transition in separateregions of the material

324 Thermal Analysis of YBa2Cu3O6+120575


Samples of R-123 have been studied by thermogravimetrycoupled withmass-spectrometry to analyze the gases evolvedduring experiments Results of the study are summarizedin Figure 7 It is seen that reversible change in mass of IP-samples occurs in the range of 430ndash900∘C that must be dueto oxygen exchange between nonstoichiometric R-123 oxidesand the gas phase taking place at these temperatures [1] MPsamples start losing mass sharply around 70∘C when heatedMass spectrometry analysis of thermal desorption productsindicates the presence of large amount of water and a smallamount of carbon dioxide contained in the samples in theform of BaCO

3(the temperature range in which the CO

2

was released and the value of 119901CO2used for thermal analysis

of the atmosphere was consistent with conditions of bariumcarbonate decomposition)

325 Study of Magnetic Properties of YBa2Cu3O6+120575

andNdBa

2Cu3O6+120575

Temperature dependences of ZFC magne-tization of the samples Y-0 Y-05 Y-2 and Y-10 are shownin Figure 8 A sharp downturn in magnetization at sim90Kobserved in the samples Y-0 Y-05 and Y-2 clearly showsthe presence of the superconducting phase Superconductingtransition temperatures of the samples Y-0 Y-05 and Y-2have been determined by taking the derivative of the mag-netization against the temperature (119889119898119889119879) Thus definedtemperatures 119879

119888are equal to 91 K for the samples Y-0 and

Y-05 and 88K for the sample Y-2 A wide transition widtharound 119879

119888= 90K indicates that both the initial and MP

samples contain inhomogeneous superconductor phaseswithdifferent 119879

119888 The following facts indicate the presence of

paramagnetic contribution in the magnetization behavior ofMP samples and its growth with increasing milling durationa significant increase in magnetization 119898 of the samples Y-05 and Y-2 compared with the initial sample Y-0 at thetemperatures 119879 gt 119879

119888 weak temperature dependence 119898(119879)

in the temperature range 100ndash300 K for MP samples asignificant increase in themagnetization of Y-10 sample at lowtemperatures

100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2

H2O (times1010) CO2 (times1011)

3

2

1

3998400

1998400

2998400

Figure 7 Thermal analysis results for samples Y-0 (1) N-0 (11015840) Y-2 (2) N-2 (21015840) and Y-10 (3) N-10 (31015840) Mass spectrometry data arerelated to the samples Y-10 (solid curves) and N-10 (dashed lines)

For comparison Figure 9 shows the temperature depen-dence of the FC magnetization in a magnetic field 119867 =500Oe for two new samples of Y-123 (120575 asymp 07) The firstsample has been freshly prepared and the other one has beensubjected to treatment at 297 plusmn 1K for 120 h at absolutehumidity of 23 120581Pa The sample with low oxygen content(and as a consequence with low 119879

119888) has been chosen due

to its relatively easy moisture saturation in these conditionswithout the use of MA (moisture saturation was controlledby the increase in weight which eventually was sim4wt)One can see that the sample saturated with water has apositive magnetic moment above the temperature 119879

119888and

shows an increase inmagnetic moment on cooling below this


N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)

Figure 8 ZFC magnetizations as a function of temperature at119867 = 50Oe for the initial and mechanically activated samplesYBa2Cu3O6+120575

(top) NdBa2Cu3O6+120575

(bottom)

temperature similarly to Y-10 sample Onset temperature ofthe magnetic anomaly in the hydrated sample is the sameas that in the freshly prepared sample This experimentdemonstrates that the presence of water in MP sampleshas a significant effect on the temperature dependences ofthe magnetization observed in samples of Y-123 series (seeFigure 8)

Temperature dependences of ZFC magnetization of MPsamples in Nd-123 series are shown in Figure 8 The super-conducting transition temperatures of the samples N-0 N-05 and N-1 are independent of milling duration and equal to119879119888sim 57KMechanical treatment leads to a substantial change

in the magnetization of MP samples throughout the inves-tigated temperature range MP samples exhibit near-room-temperature hysteretic behavior that is ZFC magnetizationis more diamagnetic than FCmagnetization It may be due tomagnetic particles of mechanoactivatedNd-123 samples or tothe presence of impurity phases whose low content or highlydisordered crystal structures do not allow to observe thesephases by X-ray diffraction measurements We also cannotexclude the formation of CuO phase (119879

119873sim 220K) at the

surface of large NdBa2Cu3O6+120575

particles proceeding undermechanical activationAt the same time a significant increasein the paramagnetic contribution to the magnetization withincreasing milling duration is observed

004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034

Figure 9 FCmagnetizations as a function of temperature of freshlyprepared YBa

2Cu3O6+120575

sample (empty points) and of hydrated sam-ple (black points) at119867 = 500Oe Inset the temperature dependenceof magnetization of hydrated sample at119867 = 10 kOe

A wide transition width around 119879119888= 57K (|Δ119879

119888sim 20K|)

in MP samples of Nd-123 series cannot be explained only bythe presence of water in the structure The observed changesindicate that during MA treatment diffusion processes asso-ciated with the ordering of the cations Nd3+ and Ba2+ appa-rently occur according to [8ndash10] that has a significant effecton 119879119888

4 Discussion of Results

41 Interaction of YBa2Cu3O6+120575


withCO2 From comparison of Figures 4 and 5 it is clear that with

increasing duration of MA processing (120591119892) the amount of

barium-containing impurities on the surface of Nd-123 sam-ples continuously increases up to 120591

119892= 10min in contrast

to the situation for the oxide Y-123 for which initially (up120591119892= 05min) sudden change and subsequent (after 120591

119892=

05min) almost stagnation in the accumulation of chemicaldegradation products were observed (see Figures 2 and 3 anddata on the impurities in YBa

2Cu3O6+120575

sample) One can seefrom Figure 7 that the degree of water saturation (120578) of bothoxides (this parameter can be traced by sharp descendingbranch of sample mass change in the temperature range of30ndash450∘C) obeys similar relationships with increasing 120591

119892 its

growth with increasing MA duration close to proportionalfor Nd-123 (120578 sim 120591

119892) and tendency of 120578 to decrease for Y-123

(120578 = 155 sdot 120591119892

03) which is close to the root dependence char-

acteristic of reagent diffusion through the reaction productslayer

Taking into account the data in [1] stating the chemicaldegradation of Y-123 is carried out on the interface betweenY-123 and gas phase and one can explain sharply fallingrates of change in concentration of its products as well as ofH2O dissolved in the oxide the diffusion path length of H

2O

and CO2reactants to the location of the reactions (1) and

(2) increases with time 120591119892 However the uniformity of the

absorption of H2O and CO

2gases by MP of Nd-123 testifies


that the thickness of the degraded layer on the surface variesslightly Apparently it does not exceed 10 nm as indicated bya weak but clear signal of the main phase which appeared inthe Ba 4d-spectrum of N-10 sample (see Figure 5) Howeverit should be noted that Nd-123 MP sample actively entersinto chemical reactionwith atmospheric CO

2 the gas escapes

from the samples quite intensively when heated in the rangeof 800ndash900∘C (see Figure 7) Therefore the question oflocalization place of products of interaction between Nd-123and atmospheric components arises

Homogeneous nucleation and growth of interaction pro-ducts in the volume of Nd

1+xBa2minusxCu3O6+120575 parent phasemaybe the answer This assumption is based on the fact that theproducts of thermal desorption of N-10 sample (see Figure 7)contain weakly bound form of CO

2escaping in a wide tem-

perature range of 200ndash550∘C Obviously it is a form of gasdissolved in the structure Since the carbonization energy ofBa2+ ions is quite high homogeneous nucleation of carbonatephase at a certain concentration (equivactivity) of CO

2in the

structure facilitated by the participation of structural defects(whose concentration should be significant in MP samples)seems quite possible



withWater In the Introductionwe have put links toworks statingthat the crucial feature for the practical application of thesuperconductor Nd-123 is its high resistance to chemicaldegradation under moisture Additional information thatexpands understanding of this feature has been received inour study Thus it is shown (see Figure 7) that a high con-centration of water accumulates in MP samples of Nd-123 indissolved form but the hydrolysis reaction development isquite limited as evidenced by the relatively low temperatureof H2O release from this oxide Moreover the results of

XRD and XPS analyzes have not detected even traces of theternary compound Nd

2BaCuO

5in these samples while it is

the compounds R2BaCuO

5due their characteristic colours

that are indicators of the hydrolysis reaction for the wholefamily of compounds R-123 [1 39 40] Thus if the hydrolysisreaction develops (there is a small peak on H

2O desorption

curve for sample N-10 at sim455∘C that can be attributed tothe chemically bound water) then it proceeds through non-traditional mechanism and with low rate

According to [41] the hydration mechanism for thehomologous series of R-123 compounds is in four stages Atthe initial stage water molecules penetrate into the bulk ofthe crystallites through the structural channels [(12) b 0]located in interspaces between CuO-chains typical for thistype of superconductors At the next stage protons whichare located in the oxygen positions of CuO-chains can besplit up of watermoleculesThis proton transfer is consideredto cause an internal (within the [CundashO]+-system) chargetransfer resulting in formation of molecular oxygen leavingthe structure At high concentrations of hydroxide ionsaccumulated in the structure the chemical decompositionof the initial oxide occurs Based on the previous schemeone can understand the reasons for high resistivity of N-123superconductor to chemical interaction with water

The authors of [42] discussed the high corrosion resis-tance of Nd-123 films in the water compared to the filmstructures of Y-123 and Eu-123 which was attributed to thepartial oxygen disorder in the planes of CuO-chains Sucha disorder should occur in Nd-123 due to the presence ofsome amount of Nd3+ ions in the sites nearby to CuO-planesof divalent barium According to the authors that shouldlead to overlapping structural channels for H

2O diffusion

and hence blocking the hydration process However ourdata on the thermal analysis (see Figure 7) illustrate thatthe saturation of Nd-123 structure with water during MAtreatment proceeds almost as fast as in Y-123 (in the rangeof 2ndash10 minutes even faster) Therefore the sought causeof the chemical stability of Nd-123 MP cannot be related toproblems of H

2O diffusion

The stage of removing oxygen from the structure is con-sidered [41 42] to be extremely important for the hydrationprocess of R-123 Thus the chemical degradation of Y-123oxide immersed in the water is completely stopped underpotential of 08 V relative to the standard electrode-saturatedsodium calomel [41] It is expected that the substitutionNd3+ rarr Ba2+ inNd-123 in addition to oxygen disordering inthe base structural plane should also lead to the strengtheningof its bondwith the lattice (due to electrostatic effect of highlycharged Nd3+ ion) [42] According to the authors [42] thisshould inhibit the reduction stage of hydration However it isimportant to consider the fact that the structure ofMP of Nd-123 contains a large amount of weakly bound CO

2 located

near Ba ions (since there is a tendency to the formation ofBaCO

3) therefore localized in the channels of the base plane

[(12) b 0] where also there is water In our opinion just theseCO2particles block channels of oxygen desorption which is

the main reason for the high stability of Nd-123 in relation tothe hydrolysis reaction

5 Conclusion

Thus as a result of mechanical activation treatment thesurface of YBa

2Cu3O6+120575

is covered by products of hydrolysisand carbonization to a considerable depth The chemicaldegradation process proceeds the normal waymdashthrough theformation of Y

2BaCuO

5phase

Chemical degradation of mechanoactivatedNdBa

2Cu3O6+120575

powders under the impact of CO2

isnot directly connected to hydrolysis process as occurs inYBa2Cu3O6+120575

(see reactions (1) and (2)) Carbonizationproceeds homogeneously through the stage of carbondioxide dissolution in the lattice of NdBa

2Cu3O6+120575

In itsturn the presence of CO

2molecules in the structure of

mechanoactivated NdBa2Cu3O6+120575

powders leads to a radicalchange in the mechanism of interaction between the super-conductor and water This mechanism eliminates the normalfor a homologous series of RBa

2Cu3O6+120575

the hydrolysisreaction with the formation of characteristic ldquocolorrdquoR2BaCuO

5phases The rate of chemical decomposition of

mechanically activated NdBa2Cu3O6+120575

by the new mecha-nism (not yet studied) is quite low


Mechanical treatment affects the temperature depen-dence of the magnetization of RBa

2Cu3O6+120575

compoundsThere is a significant increase in the paramagnetic and ferro-magnetic contributions to the magnetization with increasingmilling duration The latter leads to near-room-temperaturehysteretic behavior of NdBa

2Cu3O6+120575

samples between ZFCandFC regimes Itmay be due tomagnetic particles ofmecha-noactivated NdBa

2Cu3O6+120575

samples or to the presence ofimpurity phases whose low content or highly disorderedcrystal structures do not allow to observe these phases byX-ray diffraction measurements The mechanical treatmentdoes not have substantial influence on the transition tem-peratures of superconducting phases 119879

119888in the RBa

2Cu3O6+120575

compounds but a wide transition width around 119879119888indicates

that mechanically activated samples contain inhomogeneoussuperconductor phases with different 119879

119888 The broadening

of the superconducting transition in mechanically activatedNdBa

2Cu3O6+120575

samples may be due to redistribution ofcations between Nd- and Ba-sublattice

Finally we note that the high temperature superconduc-tor RBa

2Cu3O6+120575

subjected to mechanical activation cer-tainly has no significant advantages over conventional non-mechanoactivated material but it is obvious that physical-chemical studies of such powders reveal results interestingfrom the point of view of fundamental science

Acknowledgment

This work was supported by Russian Foundation for BasicResearch (Grant no 11-03-00317-a)

References

[1] I E Graboi A R Kaulrsquo and G Yu Metlin ldquoAdvances in scienceand technologyrdquo in Solid State Chemistry pp 3ndash142 VINITIANSSSR Moscow Russia 1989

[2] S Anders M G Blamire F-Im Buchholz et al ldquoEuropeanroadmap on superconductive electronicsmdashstatus and perspec-tivesrdquo Physica C vol 470 no 23-24 pp 2079ndash2126 2010

[3] B Ruck B Oelze R Dittmann et al ldquoMeasurement of thedynamic error rate of a high temperature superconductor rapidsingle flux quantum comparatorrdquo Applied Physics Letters vol72 no 18 pp 2328ndash2330 1998

[4] M W Rupich X Li C Thieme et al ldquoAdvances in secondgeneration high temperature superconducting wire manufac-turing and RampD at American superconductor corporationrdquoSuperconductor Science and Technology vol 23 no 1 Article ID014015 2010

[5] A Rakitin M Kobayashi and A P Litvinchuk ldquoSuperi-onic behavior of high-temperature superconductorsrdquo PhysicalReview B vol 55 no 1 pp 89ndash92 1997

[6] T Kagiyama J Shimoyama K D Otzschi et al ldquoEffect of cationcomposition and oxygen nonstoichiometry on 119869

119888-119861 properties

of Nd123rdquo Physica C vol 341ndash348 no 2 pp 1445ndash1446 2000

[7] M Badaye J G Wen K Fukushima et al ldquoSuperior propertiesof NdBa

2Cu3O119910over YBa

2Cu3O119909thin filmsrdquo Superconductor

Science and Technology vol 10 no 11 pp 825ndash830 1997

[8] C Cantoni D P Norton D M Kroeger et al ldquoPhase stabilityfor the in situ growth of Nd

1+119909Ba2minus119909

Cu3O119910films using pulsed-

laser depositionrdquo Applied Physics Letters vol 74 no 1 pp 96ndash98 1999

[9] E A Goodilin N N Oleynikov E V Antipov et al ldquoPhasestability for the in situ growth of Nd

1+119909Ba2minus119909

Cu3O119910films using

pulsed-laser depositionrdquo Physica C vol 272 6578 pages 1996[10] E Guilmeau F Giovannelli I Monot-Laffez S Marinel J

Provost and G Desgardin ldquoTop seeding melt texture growthof NdBaCuO pellets in airrdquoThe European Physical Journal vol13 no 3 pp 157ndash160 2001

[11] A I Ancharov T F Grigorrsquoeva T Yu Kiseleva A A Novakovaet al inMechanocomposites-Precursorsfor the Creation of Mate-rials with New Properties O I Lomovskii Ed p 424 Izd-voSO RAN Novosibirsk Russia 2010

[12] A Hamrita F Ben Azzouz A Madani and M Ben SalemldquoMagnetoresistivity and microstructure of YBa

2Cu3O119910pre-

pared using planetary ball millingrdquo Physica C vol 472 no 1pp 34ndash38 2012

[13] R P Vasquez ldquoIntrinsic photoemission signals surface prepa-ration and surface stability of high temperature superconduc-torsrdquo Journal of Electron Spectroscopy and Related Phenomenavol 66 no 3-4 pp 209ndash222 1994

[14] S S Gorelik L N Rastorguev and A Yu Skakov in Rentgeno-graphIcheskII I ElektronographIcheskII AnalIz p 368 Izd-voMetallurgia Moscow Russia 1970

[15] M V Reshetniak and O V Sobol Program for diffractionanalysis ldquoNew Profilerdquo(Last update 10 02 2007) Version 3 4400 (Freeware) WIN9xMENT2KXP Copyright (c) 1992-2007 ReMax SoftWare 2000

[16] M Wegmann L Watson and A Hendry ldquoXPS analysis of sub-micrometer barium titanate powderrdquo Journal of the AmericanCeramic Society vol 87 no 3 pp 371ndash377 2004

[17] A B Christie J Lee I Sutherland and J M Walls ldquoAn XPSstudy of ion-induced compositional changes with group II andgroup IV compoundsrdquo Applications of Surface Science vol 15no 1ndash4 pp 224ndash237 1983

[18] U A Joshi S Yoon S Balk and J S Lee ldquoSurfactant-freehydrothermal synthesis of highly tetragonal barium titanatenanowires a structural investigationrdquo Journal of Physical Chem-istry B vol 110 no 25 pp 12249ndash12256 2006

[19] R Caracciolo ldquoChemical characterization techniques for thinfilmsrdquo in Ceramic Films and Coatings J B Wachtman and R AHaber Eds p 376 New Jersey NJ USA 1992

[20] I N Shabanova Y A Naimushina and N S Terebova ldquoCom-position and temperature dependence of a Y-Ba-Cu-O HTSCelectronic structurerdquo Superconductor Science and Technologyvol 15 no 7 pp 1030ndash1033 2002

[21] J Beyer T Schurig S Menkel Z Quan and H Koch ldquoXPSinvestigation of the surface composition of sputtered YBCOthin filmsrdquo Physica C vol 246 no 1-2 pp 156ndash162 1995

[22] C C Chang M S Hegde X D Wu et al ldquoSurface layers onsuperconducting Y-Ba-Cu-O films studied with x-ray photo-electron spectroscopyrdquo Applied Physics Letters vol 55 no 16pp 1680ndash1682 1989

[23] X D Wu A Inam M S Hegde et al ldquoCrystalline perfectionof as-deposited high-Tc superconducting thin-film surfacesion channeling and x-ray photoelectron spectroscopy studyrdquoPhysical Review B vol 38 no 13 pp 9307ndash9310 1988

[24] P Rajasekar P Chakraborty S K Bandyopadhyay P Barat andP Sen ldquoX-ray photoelectron spectroscopy study of oxygen and


argon annealed YBa22Cu3O7minus120575

rdquo Modern Physics Letters B vol12 no 6-7 pp 239ndash245 1998

[25] J Halbritter P Walk H J Mathes B Haeuser and H RogallaldquoARXPS-studies of c-axis textured YBa

2Cu3O119909-filmsrdquo Physica

C vol 153ndash155 no 1 pp 127ndash128 1988[26] T J Sarapatka and P Mikusık ldquoXPS study of PbYBaCuO thin-

film tunnel contactrdquo Applied Surface Science vol 68 no 1 pp35ndash40 1993

[27] J A T Verhoeven and H Van Doveren ldquoAn XPS investigationof the interaction of CH

4 C2H2 C2H4and C

2H6with a barium

surfacerdquo Surface Science vol 123 no 2-3 pp 369ndash383 1982[28] C D Wagner W M Riggs L E Davis J F Moulder and G

E Mullenberg Handbook of X-Ray Photoelectron SpectroscopyPerkin-Elmer Corp Eden Prairie Minn USA 1979

[29] M C Biesinger L W M Lau A R Gerson and R S C SmartldquoResolving surface chemical states in XPS analysis of first rowtransition metals oxides and hydroxides Sc Ti V Cu and ZnrdquoApplied Surface Science vol 257 no 3 pp 887ndash898 2010

[30] X Y Fan Z GWu P X Yan et al ldquoFabrication of well-orderedCuO nanowire arrays by direct oxidation of sputter-depositedCu3N filmrdquo Materials Letters vol 62 no 12-13 pp 1805ndash1808

2008[31] S J Kerber J J Bruckner K Wozniak S Seal S Hardcastle

and T L Barr ldquoNature of hydrogen in x-ray photoelectronspectroscopy general patterns from hydroxides to hydrogenbondingrdquo Journal of Vacuum Science and Technology A vol 14no 3 pp 1314ndash1320 1996

[32] G Moretti G Fierro M Lo Jacono and P Porta ldquoCharac-terization of CuO-ZnO catalysts by X-ray photoelectron spec-troscopy precursors calcined and reduced samplesrdquo Surfaceand Interface Analysis vol 14 no 6-7 pp 325ndash336 1989

[33] H Van Doveren and J A T H Verhoeven ldquoXPS spectra of CaSr Ba and their oxidesrdquo Journal of Electron Spectroscopy andRelated Phenomena vol 21 no 3 pp 265ndash273 1980

[34] B V Crist Handbooks of Monochromatic XPS Spectra Volume2mdashCommercially pure binary oxides XPS International LLCLeona Tex USA 2005

[35] D D Sarma and C N R Rao ldquoXPES studies of oxides ofsecond- and third-row transition metals including rare earthsrdquoJournal of Electron Spectroscopy and Related Phenomena vol 20no 1 pp 25ndash45 1980

[36] V I Nefedov and A N Sokolov ldquoDegradatzia visokotemper-aturnich sverchprovodnikov pri khimicheskich vozdeistviachrdquoZhurnal Neorganicheskoi Khimii vol 34 no 11 pp 2723ndash27391989

[37] Y Uwamino T Ishizuka and H Yamatera ldquoX-ray photoelec-tron spectroscopy of rare-earth compoundsrdquo Journal of ElectronSpectroscopy and Related Phenomena vol 34 no 1 pp 67ndash781984

[38] M P Seah and W A Dench ldquoQuantitative electron spec-troscopy of surfaces a standard data base for electron inelasticmean free paths in solidsrdquo Surface and Interface Analysis vol 1no 1 pp 2ndash11 1979

[39] C H Lin H C I Kao and C M Wang ldquoKinetics andstability of R(Ba

15Sr05)Cu3O119910(R = La Nd Sm Eu Gd Dy Ho)

superconductors inwaterrdquoMaterials Chemistry and Physics vol82 no 2 pp 435ndash439 2003

[40] A G Knizhnik R A Stukan and G O Eremenko ldquoStudy theinteraction between europium HTSC of 123 type and waterrdquoSverkhprovodimost vol 4 no 1 pp 177ndash182 1991 (Russian)

[41] J Zhou R K Lo J T McDevitt et al ldquoDevelopment of areliable materials base for superconducting electronicsrdquo Journalof Materials Research vol 12 no 11 pp 2958ndash2975 1997

[42] S B Schougaard M F Ali and J T McDevitt ldquoEvidence forhigh stability against water corrosion of NdBa

2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575

and EuBa2Cu3OO7minus120575

rdquo Applied Physics Let-ters vol 84 no 7 pp 1144ndash1146 2004

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


of Nd and Ba in the structural position of each other whichcan occur during high-temperature annealing in an oxygenenriched atmosphere [9]

It is known [11] that high-intensity mechanical activa-tion processing (hereinafter MA) can significantly modifyphysicochemical properties of various materials At the sametime such researches focused on the change of the functionalproperties of superconducting oxides RBa

2Cu3O6+120575

(R-123)and to our knowledge have not yet been carried out (existingworks like [12] are devoted to mechanical activation ofprecursors) Apparently this is related to the fact that thechemical stability of these oxides to the impact of air atmo-sphere components is not high even in the normal state [1]Besides mechanical treatment leads to substantial increaseand activation of the free surface contacting with the atmo-sphere and during grinding spalling of R-123 particles occursmainly along the basal plane of the crystallites and exposesthe chemically active structural layer BaO [13] Neverthelessin the present study we have attempted to assess how muchthe surface of R-123 actually degrades under MA and justas importantly what is the influence of this effect on thefunctional properties of these superconducting oxides Wehave limited our investigations to compounds with R=Y Ndwhich are promising for applied developments

Thus the objectives of this work were (1) analysis of thechemical composition of the surface of mechanoactivatedR-123 powders (hereinafter MP) and determination of thedegree of its chemical degradation under the influence ofaggressive components of the environment H

2O and CO

2

(2) analysis of the effect of mechanical activation on thefunctional properties of the superconducting material

To fulfill the tasks we used the following methods X-raydiffraction (XRD) thermal analysis magnetometry and X-ray photoelectron spectroscopy (XPS) The latter is a power-ful tool to study the chemical and even phase compositionof the material locallymdashin the thin layer (nearly 10 nm inthickness) of the external boundary This method allowsdetecting impurity phases occurring at the average volumeconcentration outside the sensitivity of X-ray diffraction andalso phases in the amorphous state

2 Experimental Technique

Oxides R-123 were obtained by stepwise annealing a mixtureof barium nitrate Ba(NO

3)2(ldquochemically purerdquo grade) the

corresponding oxide of the rare earth element (RE) and basiccopper carbonate CuCO

3times Cu(OH)

2(ldquoespecially purerdquo

grade) at 798K for 5 h 998K (5 h) and 1213 K (140 h) Theproducts were subjected to oxidative annealing by slow (withfurnace) cooling from the synthesis temperature to 673K andexposed to this temperature in air for 3 hours The oxygencontent of the samples (6 + 120575) according to the oxidativeannealing conditions can be estimated as 690 plusmn 003 [1] Thethus obtained material was ldquoinitial samplerdquo (hereinafter IP)

In the course of our research we also needed to obtainsamples of Nd

2BaCuO

5and Y

2BaCuO

5to determine the

spectral parameters of these compounds as we did not find

relevant and reliable data in the literature They were synthe-sized at 1000∘C for 23 h from previously obtained Nd-123 andY-123 with the addition of necessary amounts of BaCO

3and

Nd2O3(Y2O3) Before the synthesis homogenized mixtures

of reagents were compressed into tabletsMechanical activation of the synthesized oxides Nd-123

and Y-123 was performed in a high energy AGO-2 planetaryball mill (set material Fe) with acceleration of milling bodiesof 60 g The initial powders were dry milled for 05 1 2 and10min The obtained materials were mechanically activatedpowders (hereinafter MP) referred to respectively as N-05N-1 N-2 N-10 (series of Nd-123) and Y-05 Y-2 Y-10 (seriesof Y-123) The particles size was determined using a scanningelectron microscope Carl Zeiss EVO 40 (Germany) andamounted to (3ndash5) sdot 10minus6m while the particles themselveswere agglomerates consisting of stuck together crystalliteswith the size of nearly 03 sdot 10minus6m

X-ray examination of samples was carried out usinga diffractometer Shimadzu XRD-7000 (Japan) The size ofcoherent scattering regions (CSR) was determined by X-raydiffraction analysis using the approximation method [14]Silicon powder was used to determine the instrumentalbroadening of the diffraction lines Selection of the functionfor approximating diffraction peaks was made using theprogram [15]

Thermal studies were carried out using the thermal ana-lyzer Netzsch STA 449C Jupiter (Germany) combined witha mass spectrometer Netzsch QMS 403C Aeolos (Germany)for evolved gas analysis The rates of heating and cooling ofsamples were 10 Kmin

Themagnetization (119898) wasmeasured using a commercialvibrating sample magnetometer Cryogenic CFS-9T-CVTIin the temperature range 42ndash300K The measurements inthe heating mode were performed on samples cooled in amagnetic field (field cooling FC) and in the absence of mag-netic field (zero field cooling ZFC)

XPS study was performed on a OmicronMultiprob spec-trometer (Germany) The test sample (RBa

2Cu3O6+120575

powderand R

2BaCuO

5ceramic tablet where R=Y Nd) was attached

to the sample holder using conductive double-sided adhesivetape and moved into the workspace of the spectrometerCeramic samples were subjected to scribing in ultrahighvacuum before study The source of the exciting radiation forXPSwasMg-anode of X-ray gunwith 170WThe energy scaleof the spectrometer was calibrated by the binding energiesof the peaks Au 4f

72(8400 eV) Ag 3d

52(36829 eV) and

Cu 2p32

(93267 eV) The value of samples surface chargewas determined by the difference between the measuredbinding energy of the C 1s signal due to CndashH groups and thevalue of 2850 eV Wide-scan survey spectra were recordedwith 05 eV energy step and the signal accumulation timeof 1 s at the pass energy (119864PE) of 100 eV High-resolutionspectrum was recorded with 005 eV energy step exposuretime of 75 s (15 scans by 05 s) and 119864PE = 20 eV Theaccuracy of peak position determination in the latter case was01 eV Decomposition of the spectra into components andextraction of the background were performed by the Shirleymethod using the program XPSPeak 41



31 Oxides Y2BaCuO

5and Nd

2BaCuO

5


5and Nd

2BaCuO

5Oxides by XRD


2BaCuO

5

and Nd2BaCuO


eters for Y2BaCuO






2O3




52) and 5286 (O 1s)


2BaCuO

5) and


2BaCuO

5at more


52)


5


2BaCuO

5sample that is




52electronic


2BaCuO

5 for


2BaCuO

5


2BaCuO

5at


2BaCuO



2BaCuO

5





andNdBa

2Cu3O6+120575


2BaCuO



2Cu3O5+x) exist-






103Ba197

Cu3O6+120575




CO2in the air






2Cu3O6+120575

under study


Cu 2p

Nd2BaCuO5

Y2BaCuO5


(a)

Nd2BaCuO5

Y2BaCuO5


C 1s

(b)

Nd2BaCuO5

BaCO3

Y2BaCuO5

BaO


Ba 3d

(c)

BaCO3

Y2BaCuO5


Y2O3

Nd2BaCuO5

Nd2O3

O 1s

(d)

Nd2O3

Nd2BaCuO5


Nd 4d

(e)

Y 3d

Y2BaCuO5

Y2O3


(f)


5and Nd

2BaCuO








2Cu3O6+120575

powders0 s

(sample Y-0)30 s

(sample Y-05)2min

(sample Y-2)10min


2BaCuO

5sim5 Y

2BaCuO

5sim7 Y

2BaCuO

5

119871 nm 167 57 25 20(2) NdBa

2Cu3O6+120575

powders0 s

(sample N-0)30 s

(sample N-05)2min

(sample N-2)10min


2Cu3O5+119909



Y-10Cu 2p

Y-2Fe 2pY-05

Y 3d Y-0Ba 4d

Ba 3d

C 1s

O 1s

0


samples




32) in the spectra


2YBa2Cu3O65+119909+ 3H2O

997888rarr Y2BaCuO

5+ 3Ba(OH)


2

(1)


3+H2O (2)








the phase Y2BaCuO

5(line Ba 3d




2BaCuO

5-phase



2O3[34] (line Y 3d

52at 1569 eV) Y-123


Ba 3d

Y-10

Y-2

Y-05

Y-0


3d523d32

(a)

Binding energy (eV)

Y 3d

Y-10

Y-2

Y-05

Y-0

150 152 154 156 158 160 162 164 166

(b)

Cu 2p


Y-2

Y-05

Y-0


2p32

2p12

(c)



5signal



5

Binding energy eV

Ba 3d52

7799 [16 17]7798lowast

7813 plusmn 01[18 19]



[22]

Y 3d52

1560 plusmn 02[21 24 25] 1587lowast

Cu 2p32

9335[21 26] 9356lowast


5312 qB[27]



[16 17]2894lowast

lowastOur data

(line Y 3d52



Y2BaCuO





2O3


2Cu3O6+120575







) and 893 eV (4d52





53)






2O3(line Nd 4d

52at 1211 eV) which


2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)







3 and Ba



2) To




120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05


Ba 4d200 400 600 800 1000



2Cu3O6+120575

samples






119896










NdBa2Cu3O6+120575



Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



31 Oxides Y2BaCuO

5and Nd

2BaCuO

5


5and Nd

2BaCuO

5Oxides by XRD


2BaCuO

5

and Nd2BaCuO


eters for Y2BaCuO






2O3




52) and 5286 (O 1s)


2BaCuO

5) and


2BaCuO

5at more


52)


5


2BaCuO

5sample that is




52electronic


2BaCuO

5 for


2BaCuO

5


2BaCuO

5at


2BaCuO



2BaCuO

5





andNdBa

2Cu3O6+120575


2BaCuO



2Cu3O5+x) exist-






103Ba197

Cu3O6+120575




CO2in the air






2Cu3O6+120575

under study


Cu 2p

Nd2BaCuO5

Y2BaCuO5


(a)

Nd2BaCuO5

Y2BaCuO5


C 1s

(b)

Nd2BaCuO5

BaCO3

Y2BaCuO5

BaO


Ba 3d

(c)

BaCO3

Y2BaCuO5


Y2O3

Nd2BaCuO5

Nd2O3

O 1s

(d)

Nd2O3

Nd2BaCuO5


Nd 4d

(e)

Y 3d

Y2BaCuO5

Y2O3


(f)


5and Nd

2BaCuO








2Cu3O6+120575

powders0 s

(sample Y-0)30 s

(sample Y-05)2min

(sample Y-2)10min


2BaCuO

5sim5 Y

2BaCuO

5sim7 Y

2BaCuO

5

119871 nm 167 57 25 20(2) NdBa

2Cu3O6+120575

powders0 s

(sample N-0)30 s

(sample N-05)2min

(sample N-2)10min


2Cu3O5+119909



Y-10Cu 2p

Y-2Fe 2pY-05

Y 3d Y-0Ba 4d

Ba 3d

C 1s

O 1s

0


samples




32) in the spectra


2YBa2Cu3O65+119909+ 3H2O

997888rarr Y2BaCuO

5+ 3Ba(OH)


2

(1)


3+H2O (2)








the phase Y2BaCuO

5(line Ba 3d




2BaCuO

5-phase



2O3[34] (line Y 3d

52at 1569 eV) Y-123


Ba 3d

Y-10

Y-2

Y-05

Y-0


3d523d32

(a)

Binding energy (eV)

Y 3d

Y-10

Y-2

Y-05

Y-0

150 152 154 156 158 160 162 164 166

(b)

Cu 2p


Y-2

Y-05

Y-0


2p32

2p12

(c)



5signal



5

Binding energy eV

Ba 3d52

7799 [16 17]7798lowast

7813 plusmn 01[18 19]



[22]

Y 3d52

1560 plusmn 02[21 24 25] 1587lowast

Cu 2p32

9335[21 26] 9356lowast


5312 qB[27]



[16 17]2894lowast

lowastOur data

(line Y 3d52



Y2BaCuO





2O3


2Cu3O6+120575







) and 893 eV (4d52





53)






2O3(line Nd 4d

52at 1211 eV) which


2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)







3 and Ba



2) To




120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05


Ba 4d200 400 600 800 1000



2Cu3O6+120575

samples






119896










NdBa2Cu3O6+120575



Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Cu 2p

Nd2BaCuO5

Y2BaCuO5


(a)

Nd2BaCuO5

Y2BaCuO5


C 1s

(b)

Nd2BaCuO5

BaCO3

Y2BaCuO5

BaO


Ba 3d

(c)

BaCO3

Y2BaCuO5


Y2O3

Nd2BaCuO5

Nd2O3

O 1s

(d)

Nd2O3

Nd2BaCuO5


Nd 4d

(e)

Y 3d

Y2BaCuO5

Y2O3


(f)


5and Nd

2BaCuO








2Cu3O6+120575

powders0 s

(sample Y-0)30 s

(sample Y-05)2min

(sample Y-2)10min


2BaCuO

5sim5 Y

2BaCuO

5sim7 Y

2BaCuO

5

119871 nm 167 57 25 20(2) NdBa

2Cu3O6+120575

powders0 s

(sample N-0)30 s

(sample N-05)2min

(sample N-2)10min


2Cu3O5+119909



Y-10Cu 2p

Y-2Fe 2pY-05

Y 3d Y-0Ba 4d

Ba 3d

C 1s

O 1s

0


samples




32) in the spectra


2YBa2Cu3O65+119909+ 3H2O

997888rarr Y2BaCuO

5+ 3Ba(OH)


2

(1)


3+H2O (2)








the phase Y2BaCuO

5(line Ba 3d




2BaCuO

5-phase



2O3[34] (line Y 3d

52at 1569 eV) Y-123


Ba 3d

Y-10

Y-2

Y-05

Y-0


3d523d32

(a)

Binding energy (eV)

Y 3d

Y-10

Y-2

Y-05

Y-0

150 152 154 156 158 160 162 164 166

(b)

Cu 2p


Y-2

Y-05

Y-0


2p32

2p12

(c)



5signal



5

Binding energy eV

Ba 3d52

7799 [16 17]7798lowast

7813 plusmn 01[18 19]



[22]

Y 3d52

1560 plusmn 02[21 24 25] 1587lowast

Cu 2p32

9335[21 26] 9356lowast


5312 qB[27]



[16 17]2894lowast

lowastOur data

(line Y 3d52



Y2BaCuO





2O3


2Cu3O6+120575







) and 893 eV (4d52





53)






2O3(line Nd 4d

52at 1211 eV) which


2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)







3 and Ba



2) To




120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05


Ba 4d200 400 600 800 1000



2Cu3O6+120575

samples






119896










NdBa2Cu3O6+120575



Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






2Cu3O6+120575

powders0 s

(sample Y-0)30 s

(sample Y-05)2min

(sample Y-2)10min


2BaCuO

5sim5 Y

2BaCuO

5sim7 Y

2BaCuO

5

119871 nm 167 57 25 20(2) NdBa

2Cu3O6+120575

powders0 s

(sample N-0)30 s

(sample N-05)2min

(sample N-2)10min


2Cu3O5+119909



Y-10Cu 2p

Y-2Fe 2pY-05

Y 3d Y-0Ba 4d

Ba 3d

C 1s

O 1s

0


samples




32) in the spectra


2YBa2Cu3O65+119909+ 3H2O

997888rarr Y2BaCuO

5+ 3Ba(OH)


2

(1)


3+H2O (2)








the phase Y2BaCuO

5(line Ba 3d




2BaCuO

5-phase



2O3[34] (line Y 3d

52at 1569 eV) Y-123


Ba 3d

Y-10

Y-2

Y-05

Y-0


3d523d32

(a)

Binding energy (eV)

Y 3d

Y-10

Y-2

Y-05

Y-0

150 152 154 156 158 160 162 164 166

(b)

Cu 2p


Y-2

Y-05

Y-0


2p32

2p12

(c)



5signal



5

Binding energy eV

Ba 3d52

7799 [16 17]7798lowast

7813 plusmn 01[18 19]



[22]

Y 3d52

1560 plusmn 02[21 24 25] 1587lowast

Cu 2p32

9335[21 26] 9356lowast


5312 qB[27]



[16 17]2894lowast

lowastOur data

(line Y 3d52



Y2BaCuO





2O3


2Cu3O6+120575







) and 893 eV (4d52





53)






2O3(line Nd 4d

52at 1211 eV) which


2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)







3 and Ba



2) To




120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05


Ba 4d200 400 600 800 1000



2Cu3O6+120575

samples






119896










NdBa2Cu3O6+120575



Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Ba 3d

Y-10

Y-2

Y-05

Y-0


3d523d32

(a)

Binding energy (eV)

Y 3d

Y-10

Y-2

Y-05

Y-0

150 152 154 156 158 160 162 164 166

(b)

Cu 2p


Y-2

Y-05

Y-0


2p32

2p12

(c)



5signal



5

Binding energy eV

Ba 3d52

7799 [16 17]7798lowast

7813 plusmn 01[18 19]



[22]

Y 3d52

1560 plusmn 02[21 24 25] 1587lowast

Cu 2p32

9335[21 26] 9356lowast


5312 qB[27]



[16 17]2894lowast

lowastOur data

(line Y 3d52



Y2BaCuO





2O3


2Cu3O6+120575







) and 893 eV (4d52





53)






2O3(line Nd 4d

52at 1211 eV) which


2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)







3 and Ba



2) To




120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05


Ba 4d200 400 600 800 1000



2Cu3O6+120575

samples






119896










NdBa2Cu3O6+120575



Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





) and 893 eV (4d52





53)






2O3(line Nd 4d

52at 1211 eV) which


2(C2O4)3[37] (line Nd 4d

52at sim1225 eV)







3 and Ba



2) To




120582119898= 2170119864

minus2

119896+ 072(119886119864

119896)12 (3)

Ba 3d

N-10Cu 2pN-2Fe 2p

O 1sN-05


Ba 4d200 400 600 800 1000



2Cu3O6+120575

samples






119896










NdBa2Cu3O6+120575



Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Ba 3d

N-10

N-2

N-1

N-05

N-0


(a)

N-10

N-1

Binding energy (eV)

Ba 4d

Ba 4d

N-2

N-05

N-0

68 72 80 84 88 92 96

Cu 3p X-ra

ysa

telli

tes

76

(b)

N-10

N-2

N-1

N-05

N-0



Cu 2p2p32

2p12

(c)

N-10

N-2

N-1

N-05

N-0


Nd 4d

(d)


powders

119864119896 (Ba 3d) 119864119896 (Ba 4d)

Phase I Phase II

Phase III

Phase I Phase II

Phase III

31205823120582

XPS

study

area

XPS

study

area

lt






527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





527790lowast

Nd 4d52

1182lowast

Cu 2p32


9348[28]

93474 plusmn 006[29 31]

9347[32] 9335lowast

O 1s 52974 plusmn 006[30 31]

53124[31] 5286lowast

lowastOur data






2




andNdBa

2Cu3O6+120575










100

99

98

97

96

95

94

93

92

100

99

98

97

96

95

94

93

92

0 200 400 600 800 1000

0 200 400 600 800 1000

14

12

10

8

6

4

3

2

Temperature (∘C)

Ion

curr

ent (

A)

Ion

curr

ent (

A)

Sam

ple w

eigh

t (

)

H2O

CO2


3

2

1

3998400

1998400

2998400





119888and



N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


N-0

N-1

N-10N-2

Y-2

Y-05

N-05

Y-0

Y-10

005 0005

0004

0003

0002

0001

0

0

minus005

minus01

minus015

minus02

minus025

minus03

minus01

minus02

minus03

003

002

001

0

0

0minus001

20 40 60 80 100 120 140119879 (K)

119898(e

mu

g)119898

(em

ug)

119898(e

mu

g)119898

(em

ug)



(bottom)







004

002

0

minus002

minus004

minus006

minus0080 20 40 60 80 100 120 140

0 20 40 60 80 100 120 140

119898(e

mu)

119898(e

mu)

119879 (K)

119879 (K)

004

0038

0036

0034


2Cu3O6+120575



119888sim 20K|)










119892=


2Cu3O6+120575


119892 its



(120578 = 155 sdot 120591119892




2O







2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



2 the gas escapes






2in the






2BaCuO





2O desorption




2O diffusion


2O diffusion


2 located





5 Conclusion


2Cu3O6+120575


2BaCuO

5phase


2Cu3O6+120575




2Cu3O6+120575





2Cu3O6+120575







2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



2Cu3O6+120575


2Cu3O6+120575


2Cu3O6+120575


119888in the RBa

2Cu3O6+120575





2Cu3O6+120575



2Cu3O6+120575


Acknowledgment


References










2Cu3O119910over YBa




1+119909Ba2minus119909




1+119909Ba2minus119909






2Cu3O119910pre-






















4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of









4 C2H2 C2H4and C

2H6with a barium




















2Cu3O7plusmn120575

relativeto YBa

2Cu3OO7minus120575












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Documents

Research Article XPS Study of Mechanically Activated YBa Cu O …downloads.hindawi.com/journals/jspec/2013/217268.pdf · 2019. 7. 31. · spectral parameters of these compounds, as