1. Physics Department, Technion, Israel Meni Shay, menishay@braude.ac.il Ort Braude College, Israel and Physics Department, Technion, Israel Phys. Rev. B 80, 144511 (2009) LEM group, PSI, Switzerland Amit Keren Gad Koren Amit Kanigel Daniel Podolsky Gerard Nieuwenhuys Elvezio Morenzoni Andreas Suter Thomas Prokscha Theoretical and Experimental Magnetism Meeting 8-9 September, 2010

2. SG Does the super-current impact the magnetic state? Research Question

3. A Picture Without a Model

4. Katano, S., Sato, M., Yamada, K., Suzuki, T., Fukase, T. “Enhancement of static antiferromagnetic correlations by magnetic field in a superconductor La 2-x Sr x CuO 4 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 YBa 2 Cu 3 O 6.45 ”, Phys. Rev. Lett. 103, 017001 (2009). Works along this line

5. How to do it? Take a s.c. wire Hold it at a constant known temperature T<T m Flow high current through it ~ J c Measure its internal magnetic order as a function of current J c ~10 5 A/cm 2 A thin wire is needed Using muon spin rotation of Low energy muons (LEM)

6. Sample Samples are prepared in the Technion in Gad Koren’s Lab 300μ 2” A long (8m) and thin (0.5x100μm 2 ) meander La 1.94 Sr 0.06 CuO 4 wire

7. Temperature Calibration Temperature accuracy ~ 0.01 K

9. Results – from Bulk samples (GPS)

10. Results

13. Interpretation & Analysis

14. 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).

18. The GL params are known Theory Experiment Integrated over a unit cell

19.  changes with I through the interaction term The magnetic transition temperature, T m, changes when current is applied Prediction Start from GL free energy Integrated over a unit cell

20. Conclusions The temperature of the magnetic phase transition is increased by the flow of a strong superconducting current