Field Induced Ferroelectric Phase in RbLiSO4

A new polar phase (phase VI) is induced in RbLiSO 4 by the external electric field. The cell dimension of phase VI is tripled in comparison with phase I ( c =3 c 0 ) and the space group is P 2 1 c n - C 2 v 9 , the same as that of the ferroelectric phase of K 2 SeO 4 . In the temperature range of phase II and III, the ferroelectric phase IV is realized at first with increasing the field, and finally a new phase appears. The phase diagram is determined by X-ray scattering.