the effect of superconducting current on the magnetic phase transition in lsco films
DESCRIPTION
The Effect of Superconducting Current on the Magnetic Phase Transition in LSCO films. Meni Shay , [email protected] Ort Braude College, Israel and Physics Department, Technion, Israel. LEM group, PSI, Switzerland. Physics Department, Technion, Israel. Gerard Nieuwenhuys - PowerPoint PPT PresentationTRANSCRIPT
Physics Department, Technion, Israel
Meni Shay, [email protected] Braude College, Israel andPhysics Department, Technion, Israel
Phys. Rev. B 80, 144511 (2009)
LEM group, PSI,Switzerland
Amit Keren Gad KorenAmit KanigelDaniel Podolsky
Gerard NieuwenhuysElvezio MorenzoniAndreas SuterThomas Prokscha
Theoretical and Experimental Magnetism Meeting8-9 September, 2010
SG
Does the super-current impact the magnetic state?
Research Question
A Picture Without a Model
Katano, S., Sato, M., Yamada, K., Suzuki, T., Fukase, T. “Enhancement of static antiferromagnetic correlations by magnetic field in a superconductor La2-xSrxCuO4 with x=0.12” Phys. Rev. B 62, R14677-R14680 (2000).
Lake B. et al. “Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor” Nature 415, 299-302 (2000).
D. Haug et al. “Magnetic-field-enhanced incommensurate magnetism in the underdoped high-temperature superconductor YBa2Cu3O6.45”, Phys. Rev. Lett. 103, 017001 (2009).
Works along this line
How to do it?
• Take a s.c. wire • Hold it at a constant
known temperature T<Tm
• Flow high current through it ~ Jc
• Measure its internal magnetic order as a function of current
Jc~105 A/cm2 A thin wire is needed
Using muon spin rotation of Low energy muons (LEM)
Sample
Samples are prepared in the Technion in Gad Koren’s Lab
300μ
2”
A long (8m) and thin (0.5x100μm2) meander La1.94Sr0.06CuO4 wire
5 10 15 20 250.0
0.1
0.2
0.3
246
0
3
6
9
Rsc
(s
ec-1
)
Temperature (K)
b
Res
isti
vity
(m
cm)
Temperature Calibration
4 6 8 10 120
5
10
15
20
T (K)
Ic1
I c1,I
c2 (
mA
) Ic2
0 5 10 15
0
10
20
30
I (mA)
45
67
8
9
V (
mV
)
T=12 K
Temperature accuracy ~ 0.01 K
Results – from Bulk samples (GPS)
BM 0.33
Results
0 2 4 6 8
0.1
0.2
Asy
mm
etry
Time (sec)
T(K), I(mA) =
7.35, 0.5 5.0, 0.5 5.0, 4.0
2.9, 0.5 3.85, 5.0
1 2 3 40.05
0.10
0.15
0.20
Asy
mm
etry
Time (sec)
T=5.003(5)K I=0.5mA Run 1775 T=4.993(6)K I=1.0mA Run 1780 T=5.002(5)K I=1.5mA Run 1778 T=5.006(5)K I=2.5mA Run 1777 T=4.998(16)K I=3mA Run 1782 T=4.997(11)K I=3.3mA Run 1783 T=5.001(8)K I=3.7mA Run 1776
Results
3 4 5 6 7 80.0
0.5
1.0
M
Temperature (K)
Low Current T
m=5.37 K 0.05
High Current T
m=5.77 K 0.05
Tm=0.4K0.1
Interpretation &
Analysis
Ginzburg-Landau Model for two interacting order parameters with
chemical potential
Special Case: SO(5) Theory Demler et. al. Rev. Mod. Phys. 76 909 (2004).
2 4( ) sF a T U
2 4( ) mb T U
2 2
smU 2
2 4( ) sG a T U
The GL params are known
20
20
2 * 2
2 * 2
2 * 2 20 0
2 20
2 *
2
/ 2
( ) 2
2
4
/
s
m m
m
U a
U bT
a T m
bT m
m e
M v
m A J
2
B
2nm
4nm
500nm
1000K
15Å
M 0.33
J
A
Theory Experiment
m
600K
U 40KsU
Integrated over a unit cell
changes with I through the interaction term
2 20
22
2T T ( ) T (0) smm m m
c
U II
b I
The magnetic transition temperature, Tm, changes when
current is applied
Prediction
Start from GL free energy
216KsmU
2 42 22
2 4
2 2
1 / c s
m m
sm
F a T I I U
b T T U
U
Integrated over a unit cell
Conclusions
The temperature of the magnetic phase transition
is increased by the flow of astrong superconducting current
1sm
s m
U
U U