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Observation of the Fulde-Ferrell-Larkin-Ovchinnikov state in the quasi-two-dimensional organic superconductor $κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$

J. Singleton·J. A. Symington·M. -S. Nam·A. Ardavan·M. Kurmoo·P. Day
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Abstract

Single crystals of the layered organic type II superconductor, $κ$-(BEDT-TTF)$_{2}$Cu(NCS)$_{2}$, have been studied in magnetic fields of up to 33 T and at temperatures between 0.5 K and 11 K using a compact differential susceptometer. When the magnetic field lies precisely in the quasi-two-dimensional planes of the material, there is strong evidence for a phase transition from the superconducting mixed state into a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, manisfested as a change in the rigidity of the vortex system. The behaviour of the transition as a function of temperature is in good agreement with theoretical predictions.

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J. Singleton, J. A. Symington, M. -S. Nam, A. Ardavan, M. Kurmoo, P. Day. 2001-05-16. Observation of the Fulde-Ferrell-Larkin-Ovchinnikov state in the quasi-two-dimensional organic superconductor $κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$. https://doi.org/10.1088/0953-8984%2F12%2F40%2F102

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