High-pressure nuclear quadrupolar resonance study of dynamical effects associated with the structural phase transition in K2OsC16

A new design for a nuclear quadrupolar resonance probe to study solids subjected to high hydrostatic pressures at low temperatures is presented. Measurements of the 35C1 spin-lattice relaxation are reported at three pressures in the temperature range just above the structural phase transition in the antifluorite crystal K2OsC16. These data are influenced by the softening of the rotary lattice mode and the evolution of a dynamic central peak. A small pressure dependence of the correlated fluctuations associated with the soft mode is observed; however, no detectable effect on the correlated fluctuations associated with the dynamic disorder component of the central peak is seen. (author). 10 refs., 1 tab., 6 figs