INCOMMENSURATE STATE OF CSCUCL3 IN A TRANSVERSE MAGNETIC-FIELD

A model of CsCuCl3 in a magnetic field parallel to the a-b planes is studied in the mean-field approximation. Over the bulk of the temperature-field phase diagram below the ordering temperature T-c, the phase sequence at constant temperature is incommensurate-->commensurate-->paramagnetic with increasing field, and the incommensurate state has winding character. The amplitude of the order parameter softens at higher temperatures, and within about 0.5 K of T-c the incommensurate state has winding character at low fields but nonwinding character at high. A direct incommensurate-->paramagnetic transition occurs at higher temperatures, with no intervening commensurate state.