NMR study of the vortex slush phase in organic superconductorκ−(BEDT−TTF)2Cu(NCS)2

Abstract

The vortex state in a single crystal of the layered organic superconductor κ-(BEDT-TTF 2 Cu(NCS) 2 , where BEDT-TTF (or ET) is bis(ethylenedithio)tetrathiafulvalene, was studied by 1 H-NMR. Under a low field region around 0.75 T, the vortex glass-liquid transition was demonstrated by a diverging of the longitudinal nuclear spin relaxation rate and peak-broadening in spectra. Under a high field region near the upper critical field H c2 (0) ≃7 T, the curvature of nuclear spin relaxation curves showed a drastic change at the temperature where the emergence of the quantum vortex slush state was reported. The mechanism in this curvature change was discussed in terms of the fluctuating field produced by fragments of vortex glass.

Rb-NMR study of the quasi-one-dimensional competing spin-chain compound Rb2Cu2Mo3Matsui1, Yagi2, Hoshino3 et al. 2017Phys. Rev. B164150View full textAdd to dashboardCite

“…The NMR spectra were obtained by plotting the spin-echo amplitude against the applied field. The nuclear spin-lattice relaxation rate was obtained by tracing the spin-echo amplitude against the repetition rate of measurement [23][24][25][26][27][28].…”

Magnetothermal instability in the organic layered superconductorκ−(BEDT-TTF)2Cu(NCS)Konoike1, Uchida2, Osada3 et al. 2009Phys. Rev. B4020View full textAdd to dashboardCite

“…Recently, it has been suggested that the vortex liquid state exists even at very low temperatures resulting from quantum fluctuations instead of thermal ones, 8,9 and the resulting liquid state is a quantum vortex slush state where a short-range order of vortices remains. 9,10 In this paper, we present the flux jump as the remarkable temperature change in the sample and preceding temperature oscillation in -͑BEDT-TTF͒ 2 Cu͑NCS͒ 2 . We have measured the dependences of the flux jumps on sweep rate, field angle, and temperature to clarify the magnetothermal instability and the vortex states in this salt.…”