Temperature dependence of Li-7 and Cs-133 spin-lattice relaxation rate in a LiCsSO4 single crystal

The temperature dependence of Li-7 and Cs-133 spin-lattice relaxation times in the LiCsSO4 single crystal has been investigated in the temperature ran ge of 140-400 K. The discontinuity in the curve of the spin-lattice relaxat ion rate near 200 K corresponds to the phase transition in the crystal. Des pite the contrasting temperature dependences of the quadrupole parameter, t he spin-lattice relaxation behaviors were quite similar for both nuclei, an d were dominated by the phonon mechanism. The temperature dependence of the relaxation rate is in accordance with the Raman process of the nuclear spi n-lattice relaxation of T-7 for T-c > T and T-2 for T-c < T. (C) 2000 Elsev ier Science Ltd. All rights reserved.