1. Institute of Physics, National Chiao Tung University
Coexistence of Ferromagnetic order and superconductivity in YBa2Cu3O7/La0.7Ca0.3MnO3 bilayers
Jiunn–Yuan Lin (林俊源)
Quantum Matter Lab
Institute of Physics, National Chiao Tung University

2. 5Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
Jiunn-Yuan Lin,1,2 Shih-Wen Huang,2,3 L. Andrew Wray,2 Horng-Tay Jeng,4,5 J. M. Lee,6 M. C. Langer,3 V. T. Tra,2 J. M. Chen,6 Y. H. Chu,7,5 S. Roy,1 R. W. Schoenlein,3 and Yi-De Chuang1
Institute of Physics, National Chiao Tung University, Hsinchu 30010, Taiwan
2Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA , USA
3Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
4Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
5Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
6National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
7Department of Materials Science and Engineering, National Chiao Tung University,
Hsinchu, 30010, Taiwan

3. Rivalry between superconductivity and ferromagnetic order
Contents
Rivalry between superconductivity and ferromagnetic order
YBCO/LCMO bilayers with termination control
Resonant soft X-ray scattering spectroscopy (RSXS)
Observation of coexistence of ferromagnetic order and superconductivity in YBCO
Control of this coexistence by termination types
12/15/2014
NCTU 2013 Summer School

4. Rivalry between superconductivity and ferromagnetism
s-wave
p-wave
d-wave
Superconducting order parameters
Ferromagnetic order parameter

5. Hi-Tc superconductor YBa2Cu3O7
d-wave supercondutivity, no magnetic order

6. Magnetism Beyond the interface

7. “The interface is the device.” ~Herbert Kroemer

9. TEM images

10. Synchrotron reflectivity measurement of a YBCO/LCMO bilayer at 80 K
With YBCO / LCMO layer thickness of 15 nm / 7.5nm
6/29/2013
NCTU 2013 Summer School

11. The bilayers are superconducting!

12. Interface magnetism of YBCO/LCMO
Chakhalian et al., 2006

13. Long range antiferromagnetic coupling across the interface due to DM interaction
G. M. De Luca et al., 2014

14. X-ray absorption spectra and resonance profile of YBCO (001) Bragg peak (resonant soft X-ray scattering spectroscopy, RSXS)

15. Schematic illustration of the experimental geometry
NCTU 2013 Summer School

16. Magnetism Beyond the interface

17. RSXS- temperature dependence

18. First principles calculations

19. No induced Magnetism Beyond the interface with La0.7Ca0.3O termination

20. RSXS- temperature dependence

21. First principles calculations

22. S-FM coexistence induces new states?
FFLO state: cooper pairs with finite momentum
H. Mayaffre et al., 2014

23. Majorona Fermions chiral p-wave superconductors
C. W. J. Beenakeer, 2013

24. Summary (S. W. Huang et al., arXiv:1504.01820)
The first observation of coexistence of ferromagnetic order and superconductivity in YBCO.
This new quantum state certainly generates new possibilities.