Effect of Hydrostatic Pressure on the Incommensurate Phase of K\u3csub\u3e2\u3c/sub\u3eSeO\u3csub\u3e4\u3c/sub\u3e

A neutron scattering study of the effect of hydrostatic pressure on the incommensurate phase transformation in K2SeO4 was performed in order to obtain information concerning the nature of the competing forces that give rise to a structural instability at a general wave vector. It was found that an increase in pressure lowers the transition temperature (dTi/dPi = - 6.5 K/kbar) and results in a smaller value of the initial incommensurate wave vector. The pressure dependence of the incommensurate to ferroelectric phase transition was also investigated (dTc/dPc = - 9 K/kbar). The latter transition displays a distinct pressure hysteresis