Supported by the National Science Foundation
DMR-1202033 (MWM), DMR-1405439 (DRT),
DMR-1157490 (NHMFL), and the
UF Center for Tomorrow’s Materials (Today!)
Mark W. Meisel and Group Members (past and present)
Department of Physics and NHMFL, University of Florida
Long-standing collaboration with Daniel R. Talham and his Group
Department of Chemistry, University of Florida
“Molecular Magnetism”: What is it? What it is NOT!
or “What I wish I knew when I was in your seat….”
Start with a Definition: (but avoid blathering….. on…. and…. on…. and….on….)
A short history of molecular magnetismhttp://www.unizar.es/magmanet/magmanet-eu/index.php?/short_history_of_molecular_magnetism.html
Molecular Magnetism Web: a gate to molelcular magnetiem(http://www.molmag.de) thanks to Jürgen Schnack
or is it Molecule-based Magnetism? (don’t trust Wikipedia….)
C. M. Hurd, Contemp. Phys. 23, 469-493 (1982)not comprehensive? where is:weak ferromagnetism,canted antiferromagnetism, …
Date: 1564
Title: Floridae
Cartographer:
Jacques Le Moyne de Morgues
http://scholar.library.miami.edu/floridamaps/first_spanish_period.php
An extra functionality dimension from ionic activity.The usual control parameters for
tuning the functionality of complex oxides—electric field E, which controls
polarization P; magnetic field H, which controls magnetization M; and stress σ,
which controls strain ɛ (A)—should be augmented (B) by the chemical potential µ to
capture the functionalities driven by mobile ions and defects in these materials (as
described by the concentration of mobile species, c).
S V Kalinin, and N A Spaldin Science 2013;341:858-859
Published by AAAS
The Art of Making a Good and Tasty Sandwich(culinary heterostructure)
salami
salami
A
B
A
A + B + A = A
A
B
C
B
A
A + B + C + B + A = B
ABA heterostructure ABCBA heterostructure
Chren pikantné
(Armoracia rusticana)
Thin breadPatina of strong mustardThick salamiPatina of strong mustardThin bread
A + B + C + B + A = D
D is new and dominate taste!
Recipe is same for nanostructures
where interfaces are important!
http://newyork.seriouseats.com/2010/10/
a-sandwich-a-day-fried-salami-at-eisenberg-sa.html
The Art of Making a Good and Tasty Sandwich(culinary heterostructure)
Alphabet Soup and Some Possible Recipes
Spin Crossover (SCO) S LS S HS + Electron Transfer =
Charge Transfer Induced Spin Transition (CTIST) S1 = 0 and S2 = 0 S1 = 1/2 and S2 = 3/2(“cooperative”, e.g. lattice distortion too)
Light-Induced Excited Spin State Trapping (LIESST)
Temperature
M = χ B
χ = C
T χ T
Talham – Meisel Chemistry-Physics Group Retreat Aug. 2014
PAQ and MKP: PhD theses
(2015)
Switching magnetism with light above 77 K in a bistable coordination polymer heterostructureOlivia N. Risset, Tatiana V. Brinzari, Marcus K. Peprah,Pedro A. Quintero, Mark W. Meisel, Daniel R. Talham, preprint
100 150 200 250 300
0.2
0.4
0.6
0.8
1.0
B = 100 G
Dark
Light
Ma
gn
etiz
atio
n [1
0-5 e
mu
G]
Temperature [K]
hν
CoFe@CrCrcore@shellnanoparticles
scale bar = 200 nm
Prussian Blue and Analogs: Magnetism
D. Davidson, L.A. Welo, J. Phys. Chem.
32 (1928) 1191.
J. Richardson, N. Elliott, J. Am. Chem. Soc.
62 (1940) 3182.
N. Holden, B. T. Matthias, P. W. Anderson,
H. W. Lewis, Phys. Rev. 102 (1956) 1463.
R.M. Bozorth, H.J. Williams, D.E. Walsh, Phys. Rev. 103 (1956) 572.
A. Ito, M. Suenaga, K. Ono, J. Chem. Phys. 48 (1968) 3597.
H.J. Buser, D. Schwarzenbach, W. Petter, A. Ludi, Inorg. Chem. 16 (1977)
2704. [x-ray structure of Fe4[Fe(CN)6]3 • xH2O]
P. Day, F. Herren, A. Ludi, H. U. Gudel, F. Hulliger, and D. Givord,
Hel. Chim. Acta 63 (1980) 148.
Reviews:
K. Dunbar and R.A. Heintz, Prog. Inorg. Chem. 45 (1997) 283.
M. Verdaguer and G.S. Girolami, “Magnetic Prussian Blue Analogs,” in
Magnetism: Molecules to Materials 5 (Wiley-VCH, 2004) 283.
man-made pigmentfrom early 1700’s
S = 1 eg
t2g
C-NFe3+
S=1/2 S=3/2
-20 0 20 4010
15
20
Magnetiza
tion (
arb
. units)
Time (Min)
Persistent Photoinduced Magnetism (PPIM)
T < TC
S = 0
t2g
eg
C-NFe2+ Co3+
S=0 S=0
Co2+
“Powders*”: O. Sato, T. Iyoda, A. Fujishima, K. Hashimoto, Science 272 (1996) 704
IrradiatedDark
“Perspective”: M. Verdaguer, Science 272 (1996) 698
* (K0.2Co1.4[Fe(CN)6] · 6.9 H2O)
10.3 Å
10.0 Å
Slide from J.-H. Park
H2OKCo Fe
C-N N-C
K0.2Co1.4[Fe(CN)6]·6.9H2O
0 10 20 30
0
1
2
3
4
5
0.0 0.5 1.0
2.5
3.0
3.5
4.0
4.5
5.0
(
10
-5 e
mu
/cm
2)
T (K)
(
10
-5 e
mu
/cm
2)
time (hours)
Persistent Photoinduced Magnetization
O. Sato et al., Science 272, 704 (1996).
Slide from D.M. Pajerowski
K0.2Co1.4[Fe(CN)6]·6.9H2O
H2OKCo Fe
C-N N-C0 10 20 30
0
1
2
3
4
5
0.0 0.5 1.0
2.5
3.0
3.5
4.0
4.5
5.0
(
10
-5 e
mu
/cm
2)
T (K)
(
10
-5 e
mu
/cm
2)
time (hours)
T = 5 K
Persistent Photoinduced Magnetization
O. Sato et al., Science 272, 704 (1996).
Slide from D.M. Pajerowski
Heterostructures of molecule-based magnets yield ….
0 20 40 60 800
5
10
15Light state
Magnetic r
esponse (
arb
. units)
Temperature (Kelvin)
Dark state
0 1 26.5
7.0
7.5
8.0
T = 60 K
Time (hours)
Light on
Pajerowski et al., J. Am. Chem. Soc. 132 (2010) 4058
… photocontrolled magnetism that is stable (> weeks) to high temperatures.
A
B
A100nm
A + B + A = D (“metamaterial”)
aka “Magnetolomics”
0 20 40 60 800.0
0.2
0.4
0.6
0.8
1.0
Single phase
Temperature (K)
MA
X
Heterostructure
FC in100 G
Persistent Photocontrolled Magnetism (PPCM) inNanoscaled Heterostructures of Prussian Blue Analogs(Prussian blue: man-made pigment from 1704)
A Ni-Cr
B Co-Fe
A 100nm
B A
Reproducible TastyProperties!
Films: Pajerowski et al.,J. Am. Chem. Soc.132 (2010) 4058
Core@Shell: Dumont et al.,Inorg. Chem.
50 (2011) 4295
B C
Core@Shell: C = Co-CrRisset et al., J. Am. Chem. Soc.
136 (2014) 15660
New Ingredient…same Tasty Properties!
Films with “spin crossover” (Fe-Pt SCO) materialGros et al., J. Am. Chem. Soc. 136 (2014) 9846
Mechanism? Irradiation with white light relaxes interface strain induced while cooling, causing rearrangement of magnetic moments near the interface.
Insight from Ni-Cr single component films studied by EPR at NHMFL.Pajerowski et al., Phys. Rev. B82 (2010) 214405
≈10 nm shell
Fe3+
Co2+
Rb+
H2O
CN-
H2O replaces CN ligand leaving a Fe
vacancy.
Rb sits in an
interstitial site.
FCC lattice
M. Verdaguer,
Science 272
(1996) 698
(and “charge balance”!)
Defects instructures are a level of Complexity!
Ingredient 1: Photoactive Component: CoFe Prussian Blue analogue (PBA)
Rbj Cok [Fe(CN)6]l • n H2O
(variables are j , k , l , n )
Note M-CN-M’bridging!
Co/Fe = 1.5
Co/Fe = 1.37
Co/Fe = 1.32
Co/Fe = 1.26
Co/Fe = 1.15
350 K50 K
5
0
High Spin
Low Spin
T vs. T
plots
Shimamoto, Ohkoshi,
Sato, Hashimoto,
Inorg. Chem.
41 (2002) 678
CTIST: Charge Transfer InducedSpin Transition (HS to LS by cooling)
HetroStructured Layered Film : Co-Fe / Ni-Cr (CN)6
~ Co-Fe
Co-FeNi-Cr
Ni-Cr
High TC
PhotoinducedMagnet ?
Co Fe Ni Cr
0
1 2 3
4
B
BA
A
A
B
A ~ 10 Å
A: Photoinduced Magnet
B: High TC Magnet
A + B = ?
Ideas motivated by: M. Nishino, Y. Yoshioka,
K. Yamaguchi, Chem. Phys. Lett. 297 (1998) 51
J.-H. Park, Ph.D. thesis (2006) Univ. of Florida
Ingredient 2: Ferromagnetic Component: NiCr Prussian Blue analogue (PBA)
Slide from J.-H. Park
Long-Range vs. Short-Range Ordering
Magnetic Coherence Length: ξ (T, spatial/spin dimensions, …)
Characteristic Length of Scale of Sample: ℓ(“structural coherence length”)
ℓ
ξ
ℓ < ξ : Short-Range “Order” (“spin liquid”):
Interactions/correlations at short distances
Fingerprints: Curie or Curie-like with
no TC , ...
ℓ > ξ : Long-Range “Order” (“spin solid”):
Interactions/correlations at long distances
Fingerprints: “bulk” TC , Coercive Magnetic
Field, …
Curie-Weiss Law: = _ C_
T+ Θ
ℓ
ξ
ℓ ~ ξ : “Intermediate Order” :
Fingerprints: 0 < Tc < Tc(bulk), ...ξ
ℓ
0 20 40 60 800
5
10
15Light state
Magnetic r
esponse (
arb
. units)
Temperature (Kelvin)
Dark state
0 1 26.5
7.0
7.5
8.0
T = 60 K
Time (hours)
Light on
D.M. Pajerowski et al., J. Am. Chem. Soc. 132 (2010) 4058
A
B
A100nm
0 20 40 60 800.0
0.2
0.4
0.6
0.8
1.0
Single phase
Temperature (K)
MA
X
Heterostructure
Result 1: Thin films ABA (NiCr-CoFe-NiCr) Prussian Blue analogues (PBA)
Extra Important Points:
White Light (vs monochromatic)
Lengths ≳ 50 nmsmaller lengths:N. Dia et al., Inorg. Chem. 52 (2013) 10264M. Presle et al., J. Phys. Chem. C 118 (2014) 13186
other morphologies: D.M. Pajerowski, PhD thesis (2010)
Low concentration(add very slow…)
NiIICl2K3CrIII(CN)6
Multilayered Heterotructure
CoIICl2K3FeIII(CN)6
RbCoFe PBA
KNiCr PBA
200nm
Control of the Nucleation
(10 x the excess ofCores vs. precursor)
Result 2: CoFe@NiCr-PBA core-shell nanoparticles
Slide from M.F. Dumont
0 20 40 60 80
0
10
20
30
40
(
cm
3 / m
ol C
oF
e)
T (K)
dark - light
0H = 100 G
0 20 40 60 800
50
100
150
200
250
(
cm
3 / m
ol C
oF
e)
T (K)
dark
light
0H = 100 G
0 20 40 60 800
40
80
120
(
cm
3 / m
ol C
oF
e)
T (K)
dark
light
0H = 100 G
0 20 40 60 800
20
40
60
(
cm
3 / m
ol C
oF
e)
T (K)
dark
light
0H = 100 G
0 20 40 60 80
0
10
20
30
40
(
cm
3 / m
ol C
oF
e)
T (K)
dark - light
0H = 100 G
0 20 40 60 80
0
10
20
30
40
(
cm
3 / m
ol C
oF
e)
T (K)
dark - light
0H = 100 G
~ 80 nm shell ~ 100 nm shell ~ 160 nm shell
Result 2: CoFe@NiCr-PBA core-shell nanoparticlesMechanism and Extent of Interface Strained Region
E.S. Knowles et al., Polyhedron 66 (2013) 153; E.S. Knowles, Ph.D. thesis (2013)
Result 3: CoFe@CoCr-PBA core-shell nanoparticles (Change of Ingredient)Mechanism and Extent of Interface Strained Region
Light-Induced Changes in Magnetism in a Coordination Polymer Heterostructure … Olivia N. Risset, Pedro A. Quintero, et al., J. Am. Chem. Soc. 136 (2014) 15660.
Interfaced Strained Region (ISR) extends to about 25 nm in Shell.
Thickness of Shell influences Core and ISR and Domain rearrangement.
Fe(azpy)[Pt(CN)4]
Agustí et. al. Chem. Mater. 2008, 20, 6721
a (Å) c (Å) Volume (Å3) Fe-Neq (Å) Fe-Nax (Å)
HS 7.41 ± 0.02 13.37 ± 0.05 734 ± 4 ------ ------LS 7.16 ± 0.04 12.98 ± 0.03 665 ± 6 ------ ------
Δ (HS→LS) 0.25 ± 0.04 0.39 ± 0.06 69 ± 7 0.18 ± 0.03 0.20 ± 0.03
a
c~ 300 K
S = 0 S = 2
Ingredient 1: Photoactive Component: Spin-crossover (SCO)Hofmann-like framework (Change of Ingredient)
Light-Induced Excited Spin State Trapping = LIESST
Result 4: Films of SCO Fe-Pt and NiCr-PBA (Change of Ingredient)
Light-Induced Magnetization Changes in a Coordination Polymer Heterostructure …Corey R. Gros, Marcus K. Peprah, et al., J. Am. Chem. Soc. 136 (2014) 9846.
SCO Fe-Pt
Glass
NiCr-PBA
Result 5: Platelets of SCO Fe-Ni and NiCr-PBA (Change of Ingredient)
NiCr-PBA/Fe(azpy)[Ni(CN)4] : Marcus K. Peprah, Corey R. Gros, et al., in preparation
100 150 200 250 300
0.2
0.4
0.6
0.8
1.0
B = 100 G
Dark
Light
Ma
gn
etiz
atio
n [1
0-5 e
mu
G]
Temperature [K]
hν
CoFe@CrCrcore@shellnanoparticles
scale bar = 200 nm
Result 6: CoFe@CrCr-PBA nanoparticles (Change of Ingredient)
Switching magnetism with light above 77 K in a bistable coordination polymer heterostructureOlivia N. Risset, Tatiana V. Brinzari, Marcus K. Peprah,Pedro A. Quintero, Mark W. Meisel, Daniel R. Talham, preprint
Early attempts and hints: Elisabeth S. Knowles, Ph.D. thesis (2013)
Now Persistent Magnetism changes thermally compromised by CoFe-PBA electron relaxation.
Can the Interface Strained Region magnetic domains possess memory to CrCr-PBA TC = 220 K?
Co/Fe = 1.5
Co/Fe = 1.37
Co/Fe = 1.32
Co/Fe = 1.26
Co/Fe = 1.15
Shimamoto, Ohkoshi,
Sato, Hashimoto,
Inorg. Chem.
41 (2002) 678
350 K50 K
350 K5 K
5
0
High Spin
Low Spin
T vs. T
plots
NaxCoy[Fe(CN)6]z •nH2O
T vs. T
plots
Persistent Photocontrolled Magnetism (PPCM) inNanoscaled Heterostructures of Coordination Polymers[PBA = Prussian blue analogue]
A NiCr-PBA
B CoFe-PBA
A 100nm
B A
Reproducible TastyProperties!
Films: Pajerowski et al.,J. Am. Chem. Soc.132 (2010) 4058
Core@Shell: Dumont et al.,Inorg. Chem.
50 (2011) 4295
B C
Core@Shell: C = CoCr-PBARisset et al., JACS136 (2014) 15660
New Ingredient…same Tasty Properties!
Films with “spin crossover” Fe-Pt SCO / NiCr-PBAGros et al., J. Am. Chem. Soc. 136 (2014) 9846
100 150 200 250 300
0.2
0.4
0.6
0.8
1.0
B = 100 G
Dark
Light
Ma
gn
etiz
atio
n [1
0-5 e
mu
G]
Temperature [K]
hν
CoFe@CrCrcore@shellnanoparticles
scale bar = 200 nm
Core@Shell:CoFe@CrCr-PBA
adding externalpressure…
add chemicaltuning…Road to 300 K?
1 2 3
4
5 Fe-Ni SCO / NiCr-PBA
6
7
Date: 1564
Title: Floridae
Cartographer:
Jacques Le Moyne de Morgues
http://scholar.library.miami.edu/floridamaps/first_spanish_period.php
Join the Exploration!
Learn the ABCD’s:Always Be Collecting Data
F3: Form Follows Function
SOC: Spin Orbit Coupling
Think and Do!
We are colleagues!
Now some “canned” slides for potential questions.
Rb0.8Ni [Cr(CN)6]0.7·nH2O
Phys. Rev. B 82 (2010) 214405
Demagnetizing Factors!
Magnetic anisotropy in thin films of Prussian blue analogues
Phys. Rev. B 82 (2010) 214405
D.M. Pajerowski, J.E. Gardner, M.J. Andrus, S. Datta,A. Gomez, S.W. Kycia, S. Hill, D.R. Talham, M.W. Meisel
116 GHz
External Pressure tuning of the Magnetic Response in CoFe-PBA
Domain distortion in CrCr-PBA persists to Tc,which is Pressure Depedent.
100 150 200 250 300
0.00
0.02
0.04
0.06
0.08
0.10
0.12 September 2014
MP163: 109BC1-2 : CoFe@CrCr
White Light (no filter)
FC in 100 G, 0H = 100 G
Optical Presssure Probe 2.0
[ M
da
rk (
T)
- M
ligh
t(T
) ]
/ M
da
rk(T
= 3
00 K
)
Temperature (K)
P = 2.55 GPa
irradiation at 80 K
CrCr-PBA
TC Bulk
CoFe-PBA
TCTIST
Result 7: CoFe@CrCr-PBA nanoparticles (Light and Pressure) (Change of Environment)
Z. Mitróová et al., Acta Phys.Pol. A 133 (2008) 469
E.S. Knowles,Ph.D. thesis (2013)
10.4 Å10.3 Å
10.0 Å
APS – ANL dataunder analysis…A. Felts et al.
Laure Catala and Talal Mallah and coworkers
Small (< 30 mn) core@shellCoFe-PBA@NiCr-PBA:
Linkage Isomerism? (unpublished)
M. Verdaguer and G.S. Girolami (2004):“The solid Prussian blue analogues can also suffer from one or more of the following problems: (4) Linkage Isomersism”
Time, strain, interface… Irreversible / Reversible
“High pressure neutron scattering of the magnetoelasticNi-Cr Prussian blue analogue,” D. M. Pajerowski, S. E. Conklin, J. B. Leão, D. Phelan, L. W. Harriger, Phys. Rev. B 91, 094104 (2015)
(and untold story of route to T > 200 K)
High-TC core-shells?
50 100 150 200 250 3000
1
2
3
4
M (
10
-5 e
mu G
)
T (K)
dark
light
0H = 100 GA
0 50 100 150 200 250 3000.0
0.5
1.0
1.5
M (
10
-3 e
mu
G)
T (K)
CAB
dark
light
0H = 100 G
*heterogeneous (“chunks” of B in sample)?E. S. Knowles et al., unpublished.
CoFe-PBA
NiCr-PBA
CrCr-PBA
Diamagnetic FeII(LS, S = 0) – CN - CoIII(LS, S = 0)
Ferrimagnetic FeIII(LS, S=1/2) – CN - CoII(HS, S=3/2)
O. Sato, Y. Einaga, A. Fujishima, K. Hashimoto, Inorg. Chem. 38 (1999) 4405.
T. Kawamoto, Y. Asai, S. Abe, Phys. Rev. Lett. 86 (2001) 348.
(ab initio quantum cluster calculations)
“Hunch”: distribution of energy barriers exist due to
local environment.
Photoinduced Magnetism in Cobalt-Iron Cyanide