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| VOLUME 110 (2019) | ISSUE 1 | PAGE 68 |
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Temperature dependence of the critical field of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br
V. A. Gasparov+, A. Audouard*, L. Drigo×, J. A. Schlueter°
+Institute of Solid State Physics Russian Academy of Sciences, 142432 Chernogolovka, Russia *Laboratoire National des Champs Magnetiques Intenses (UPR 3228 CNRS, INSA, UPS, UGA), F-31400 Toulouse, France ×Géosciences Environnement, 31400 Toulouse, France °Materials Science Division, Argonne National Laboratory, Argonne, IL 60439-4845, USA
Abstract
We present upper critical magnetic fields data for κ(BEDT-TTF)2Cu[N(CN)2Br (hereafter k-Br), single crystals with the magnetic field applied either or perpendicular and parallel to the conducting layers. The H-T phase diagram in this single crystals has been deduced from tunnel diode oscillator-based contactless measurements in pulsed magnetic fields up to 56 T for the inter-plane (H|b) and in-plane (H|ac) field directions. Temperature dependence of the magnetic penetration depth in DC fields is also reported. The temperature dependence of the upper critical magnetic field Hc2(T) is not accounted for the Werthamer-Helfand-Hohenberg model for in-plane configuration. For the inter-plane orientation, a significant upward curvature is observed as the temperature decrease, in the range close to Tc, followed by saturation at lower temperatures. Possibly, this upturn is an indication of flux-line lattice melting. |