1 / 26

Does FFLO state exist in field-induced superconducting phase of l -(BETS) 2 FeCl 4 ?

Does FFLO state exist in field-induced superconducting phase of l -(BETS) 2 FeCl 4 ?. Shinya UJI National Institute for Materials Science and Univ. of Tsukuba Tsukuba, JAPAN. In collaboration with T. Yamaguchi, T. Konoike, and K. Enomoto NIMS H. Cui, H. Kobayashi

tuwa
Download Presentation

Does FFLO state exist in field-induced superconducting phase of l -(BETS) 2 FeCl 4 ?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Does FFLO state exist in field-induced superconducting phase of l-(BETS)2FeCl4? Shinya UJI National Institute for Materials Science and Univ. of Tsukuba Tsukuba, JAPAN In collaboration with T. Yamaguchi, T. Konoike, and K. Enomoto NIMS H. Cui, H. Kobayashi Institute for Molecular Science T. Tanaka, M. Tokumoto AIST A. Kobayashi Univ. of Tokyo E. S. Choi, D. Graf, T. Tokumoto, J. S. Brooks NHMFL

  2. Introduction Field induced superconductivity in l-(BETS)2FeCl4

  3. Cl- Fe3+ Crystal Structure of l-(BETS)2FeCl4

  4. S.Uji, et al. Narture (2001) • L. Balicas, et al. • Phys. Rev. Lett. 87, 067002 (2001) High field phase diagram in l-(BETS)2FeCl4 Field induced superconducting phase Superconductivity disappears as B is tilted form the layers.

  5. Jaccarino-Peter compensation mechanism l-(BETS)2FeCl4 Zeeman effect is suppressed when B~Bj. B~Bj If B // plane…. Orbital effect is also suppressed!

  6. FFLO state? FFLO=Fulde-Ferrell-Larkin-Ovchinnikov • L. Balicas,et al. • PRL87, 067002 (2001) l-(BETS)2FeCl4 Order parameter mixing between s and p waves FFLO Vortex Vortex FFLO M. Houzet et al. PRL 88, 227001 (2002) H. Shimahara, JPSJ71, 1644 (2002)

  7. Large Internal Field l-(BETS)2FeCl4 magnetic sub-bands Formation of two 2D FS

  8. l-(BETS)2GaCl4 Large Internal Field l-(BETS)2FeCl4 l-(BETS)2FeCl4 Formation of two 2D FS

  9. k k’ D=0 q FFLO state: Non-uniform order parameter k+k’=q=mBBeff /vF Beff=B-Bint Up spin Down spin D(r)=Dcos(qr) D FFLO state r 0 nodal planes 2D Fermi surface FFLO state ? UPd2Al3, CeRu2, UPt3, UBe13, CeCoIn5, k-(ET)2Cu(NCS)2, l-(BETS)2GaCl4..? l=2p/q

  10. Can FFLO state be stabilized? l-(BETS)2FeCl4 O.K! Necessary conditions 1) Large spin susceptibility 2) Clean limit 3) Orbital effect quenched large paramagnetic Fe spins observation of SdH oscillation under in-plane fields FFLO state?

  11. c q ? q a k q k’ band structure calculation Possible q vector in FFLO state D(r)=Dcos(qr) For isotropic case, q//B For 2D case, q: unknown

  12. D=0 q Purpose of this study FFLO state really exists ? Get the evidence of the order parameter oscillation.

  13. Experiments up to 25 T at NIMS successive anomalies in resistive transitions

  14. Superconducting Transition -I I B//c

  15. b* B a’ q c Field angular dependence

  16. Lock-in transition Josephson Vortex motion B Tilted flux lines strong pinning Lock-in transition B I Josephson vortices (in insulating layers) B Weak pinning. Lorentz force depinning resistance

  17. Josephson vortex dynamics Energy dissipation of Josephson vortex motion

  18. Experiments up to 45 T 45 T hybrid magnet experiments at NHMFL

  19. Resistive transitions H //c

  20. How sensitive to angle? H //c Nothing in tilted fields

  21. metal super. Phase diagram for H//c

  22. Model:periodic Josephson vortex pinning

  23. Periodic strong pinning for B//c Bulaevskii et al. Phys.Rev. Lett. 90 (2003) 067003 B//c Order parameter N S c 0 FFLO state q//a Vortices commensurability effect node s=20A Josephson vortex

  24. Periodic strong pinning for B//c commensurability condition commensurability effect node s=20A Josephson vortex uniform super. FFLO FFLO metal super. l d H 32T

  25. Results for H//a Order parameter c 0 q//a B//a No commensurability effect

  26. Summary l-(BETS)2FeCl4 1) Successive anomalies in R(H) curves 2) No such features in tilted fields 3) Hysteresis in I-V curves FFLO state? commensurability between l and d l : node period d: vortex lattice Acknowledgements NHMFL people for use of 45 T hybrid magnet

More Related