  The vortex state in a single crystal of the layered organic superconductor
\kappa-(BEDT-TTF2Cu(NCS)2, where BEDT-TTF (or ET) is
bis(ethylenedithio)tetrathiafulvalene, was studied by 1H-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 Hc2(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.
