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Superconducting Fluctuation of the Layered Organic Superconductor κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br in Magnetic Susceptibility

2013; Physical Society of Japan; Volume: 82; Issue: 7 Linguagem: Inglês

10.7566/jpsj.82.073706

1347-4073

Tomotaka Uehara, Miho Ito, Hiromi Taniguchi, Kazuhiko Satoh,

Magnetism in coordination complexes

A quasi-two-dimensional organic superconductor, κ-(BEDT-TTF)2Cu[N(CN)2]Br [BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene], showed fluctuation behavior of superconductivity up to approximately 19 K, which was far higher than the zero-field transition temperature \(T_{\text{c}}\) (\(=11.6\) K). We measured magnetic susceptibility under a magnetic field parallel and perpendicular to the conducting layers and determined the susceptibility difference Δχ between the parallel-field and perpendicular-field susceptibilities as functions of temperature and magnetic field. From the analysis of the magnetic field evolution of Δχ, we deduced that Δχ was composed of anisotropy in normal-state magnetic properties and superconducting fluctuations. From the investigation of Δχ in the low-field region, we derived that the fluctuation component was proportional to (T-Tc)α with a constant α (-2.3<α<-2.0) or to T(T-Tc)β with a constant β (-2.4<β<-2.1).