Superconducting fluctuations and the reduced dimensionality of the organic superconductor κ-(BEDT-TTF) 2 Cu(NCS) 2 as observed through measurements of the de Haas-van Alphen effect

We report measurements of the de Haas\char21{}van Alphen (DHVA) effect and ac susceptibility in the layered organic superconductor $\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}\mathrm{Cu}(\mathrm{NCS}{)}_{2}.$ The amplitude of the DHVA oscillations is attenuated over a wide field range above the irreversibility line, ${B}_{\mathrm{irr}}(B),$ below which a rigid flux lattice is formed. Thus the DHVA effect provides a unique probe of the superconducting fluctuations at high fields in this material. We compare our measurements with other measurements of the superconducting phase diagram of $\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}\mathrm{Cu}(\mathrm{NCS}{)}_{2}.$