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P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Superconductivity 101
A Primer for Engineers
Paul M. Grant
[email protected]/staff_papers/sst
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Fathers of Electricity
DiscoverersDiscoverers
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999Fathers of Electricity
PractitionersPractitioners
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Fathers of Cryogenics
Dewar Kammerlingh-Onnes
CH4 112 KO 90N2 77Ne 27H2 20He 4.2
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
(((
Models of Electrical Conductivity
The First Idea:R
T
Just Goesto Zero!
(((
(((
(((
• •e-e-
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
The Most Popular:R
T
Freezes Out!e-
Models of Electrical Conductivity
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Models of Electrical Conductivity
Reality:R
T
Limited byImpurities!
•e-
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Thus the mercury at 4.2 K has entered a new state, which, owing to its particular electrical properties, can be called the state of superconductivity
H. Kamerlingh-Onnes (1911)
1911A Big Surprise!
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Magnetic Properties
0
-1/4
T
H offH on0
-1/4
T
H onH on
Expected (Lenz’ Law) Weird ! (Meissner Effect)
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999They all tried…
and failed!
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
They came close...FritzLondon
LevLandau
IrwinFroehlich
“The B-field does penetrate.”
E ~ 2 dJ/dt, B ~ 2 J
“Since SC is a second-order phase transition, there must be an order parameter involved.”
“TC depends on the mass of the atoms (isotope effect), so the SC must be tied to lattice vibrations (phonons).”
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 They Got It Right!B ----- C ----- S
Bardeen: “It’s a macroscopic quantum state”Cooper: “It’s got twice the charge you’d expect”Schrieffer: “’s a statistical wavefunction”
There has to be a regimewhere the lattice vibrationsact to bind electrons togetherrather than scatter them withloss as given by Ohm’s Law.
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Physics of Superconductivity
+ +
+ +•e-
•e-
Electrons Pair Off!
)/1exp( 14.1 DCT
BCS Equation
(Niobium) K 5.9
,28.0
,K 275
C
D
T
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 “Cooper’s Problem”
F er m ion -B oson F eyn m an D iagr am
q
k1
k'1
k2
k'2
C ooper P r ob lem
·
·
2D
s ingle partic les
pairs
e ik r1
e -ik r2
H(k) + H(-k ) + V(k)
V(k) = -V0 0 k f dk e ik (r1 - r2)
y(r1-r2) = f(r1-r2)(s 1,s 2)
2D ~ e -2/N(E f)V 0
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Important Numbersin Superconductivity
Transition Temperature, TC Way below 300 K
Critical Current Density, JC 10-2 - 106 A/cm2
Critical Magnetic Field, HC 10-4 - 10 T
London Penetration Depth, 10 - >1000 Å
Pippard Coherence Length, 10 - >1000 Å
G-L Parameter, = / 0.01 - 100
NB! All these numbers depend on eachother. E.g., HC ~
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 TC vs. Year:1911 - 1980
Year
0
5
10
15
20
25
1900 1910 1920 1930 1940 1950 1960 1970 1980
Te
mp
era
ture
(K
)
Hg
Pb
NbN V3Si
Nb3Sn
Nb3Ge
Cubic Metals
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
MRI & “Big Physics”
Magnetic Resonance ImagingPhilips
TevatronFermi National Laboratory
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 1986Another Big Surprise!
Bednorz and MuellerIBM Zuerich, 1986
Onset TC = 40 K !
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 1987“The Prize!”
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 March 3, 1987“123” Discovered
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999Woodstock of Physics
NYC, 1987Physicists’ Night Out!
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Y-123
Bi-2223
HTS Layered Perovskites
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 TC vs. Year:1911 - 1999
1900 1920 1940 1960 1980 2000 0
50
100
150
200T
emp
erat
ure
, T
C (K
)
Year
Low-TC
Hig
h-T
C
164 K
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 HTSC Phase Diagram
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
HTS Theories
Phil Anderson
“It can’t be just an accident that hightemperature superconductivity occurs in ahost material whose insulating state is anantiferromagnet, and, which when dopedwith holes to a level where magnetic behavior disappears, we get superconductivity.”
Current Situation:• The pair coupling is believed to be magnetically mediated.• The normal conducting state is believed not to be a Landau liquid.• The superconducting state is domain- like, occurring as electronic “stripes.”
However, there is yet no generally accepted model today!
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Boson Flavors
Phonons
P olar ons
A n yon s
S lav e -B o so n s
P las mons
E xci ton s
F er m ion -B oson F eyn m a n D ia g r a m
q
k1
k'1
k2
k'2
H ubbar d H amiltonian
H = åi [t(c ic*i+1 + h .c .) + U n in i]
t = Hopping Integral
U = C oulomb R epuls ion
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Ultimate Boson
Put-ons!
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
GLAG
( ) ( )
( ) ( )
(| | )
( / )
/
* *
i f f f
i f f f f f
a b f
A
L
f
A
A A
A
2 2
2 12
2
12
0
1 0
0
2
1 2
1 2
I
II
G d rm
i e A i e A a b[ ] [*
( * ) *( * ) * * *]f f f ff ff ff 3 12
1
2
Lev Gor’kov
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
IrreversibilityLine
Mixed
NormalHC2
Mag
net
ic F
ield
TCTemperature HC2
1/4
Type II Superconductivity
Mixed
HC2
Meissner
HC1
HC2Normal
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
H
J
FLorentz Defects (pin sites)
Abrikosov Vortex Lattice
DipoleForce
FLorentz
J
H
Type II Superconductor in the Mixed State
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Hg-1212:Fission-Induced Defects
• L. Krusin-Elbaum, et al., Nature
• World record Hirr at 77 K in Hg-1212
• Hg-1212 Prototype Tapes made at TCSUH
• Potential for high-field magnet inserts
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Extrinsic Pinning
10 m 10 m
DECORATED VORTEX ARRAYS
with random heavy ion tracksclean
M. Leghissa, et al. Phys. Rev. B48, 1341 (1993)
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
FLorentzMoving Vortex Lattice
(elastic flow)
(plastic flow)
(moving liquid)
H
T
HC2
HC1
TC
Normal State
Meissner State
Vortex Liquid
Mag
neti
c F
ield
Static Phase Diagram
Vortex Glass
Bose Glass
Polymer Glass
Vortex Lattice
Vortex MatterStatic Phase Diagram
Temperature
Mag
neti
c F
ield
Dynamic
Phase D
iagra
m
TC
HC2
HC1
FLorentzElastic Flow
Plastic Flow
Liquid Flow
Normal
LiquidGlass
SolidBose Glass
Polymer Glass
Melting Line
Meissner State
SC
Flu
ctuatio
n
Regim
e
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.008.00 9.00
10.00
85
70
50200
1
2
3
4
5
6
Jc(B
,T)/J
c(0,
77)
B(T)
T(K)
ASC Bi-2223 OPIT TapeNormalized Jc, B||ab
85777064503520
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.009.00 10.00
2050
70
85
0
1
2
3
4
5
6
Jc(B
,T)/J
c(0,
77)
B(T)
T(K)
ASC Bi-2223 OPIT TapeNormalized Jc, B||c
20355064707785
JC(B,T) for BSCCO
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999BSCCO OPIT/Ag E-J Characteristic
Typical E vs J Power Law
0.0E+00
5.0E-06
1.0E-05
1.5E-05
2.0E-05
0 25000 50000 75000
J (A/cm^2)
E (
V/c
m)
E = aJn
n = 15
T = 77 K
E = 1 V/cm
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 Solenoid Loop Current: t > t0
L
R(I)
I(t)
bI LdIdt
0
I(t)b(n 1)L
(t t ) I
n
0 01 n
1
1 n
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999 “Persistent” Current Decay
Persistent Current Decay
0
50
100
150
200
250
300
350
400
450
1.0E-01 1.0E+01 1.0E+03 1.0E+05 1.0E+07t (sec)
I (A
)
B = 0.50 T
B = 0.25 T12 Days
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Type II Hysteresis
H
M
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
Hysteretic ac Loss
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
The Future 2028
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999
The Future
700 K !
May, 2028
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999Electricity:
A Life NecessityCalifornia, Summer 1996
Quebec, Winter 1997
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999“You can’t always get
what you want…”
P. M. Grant
Superconductivity 101
Superconductivity Workshop
Charlotte, 24 May 1999“…you get what you
need!”