Dielectric constant in the incommensurate phase of NH₄HSeO₄ under electric field

Abstract

The temperature dependence of the dielectric constant has been measured in NH₄HSeO₄ crystal at bias electric field. It is shown that the temperature of phase transition from the incommensurate to the commensurate phases depends nonlinearly on the applied electric field. Lifshitz point has been reached at field 1.1 MV/m.