205Tl NMR spin-lattice relaxation in the mixed state of TL/sub 2/BA/sub 2/CUO/sub 6/ (T/sub c/=100K) : effect of vortex motion and spin diffusion

Summary form only given, as follows. Temperature dependences of the ²⁰⁵Tl spin-lattice relaxation rate, W, has been measured in the mixed state of a Tl₂,Ba₂Cu0₆ aligned powder sample with T_C=100K in a wide range of magnetic fields. Behavior of the measured curves indicates the coexistance of three relaxation mechanisms: fluctuations of pancake vortices, spin diffusion to the vortex cores, and spin fluctuations from paramagnetic impurities. The former source is responcible for the linear temperature dependence of the relaxation rate at the low-temperature region (T < 25K) while the latter one manifests itself as a temperature-independent background.