A New Ferroelectric Phase and a Field Induced Phase of LiRbSO₄

Abstract

The structural phase transition in LiRbSO₄ has been reinvestigated by means of microscopic observation, dielectric measurement and X-ray scattering. The general feature of successive transitions was reconfirmed. But a new ferroelectric phase was found between the incommensurate phase II and the commensurate phase III, in a narrow temperature range around 473 K. The satellite reflections in this phase are characterized by a commensurate wavenumber k_z=(3⁄7)c^*. Under an electric field, the same modulation wavenumber is also recognized between the phase III and the ferrielectric phase IV, where fourfold D–E hysteresis loops are observed.