Metastable ferroelectric phase in potassium dihydrogen phosphate induced by a static electric field

Raman scattering experiments show that potassium dihydrogen phosphate cryst als undergo a metastable ferroelectric phase transition induced by a static electric field at 119 K. Qualitative changes occur in the Raman spectra of all possible scattering geometries for applied d.c. electric field intensi ties of the order of 4 kV cm(-1). The phase transition is induced by rotati on of phosphate ions changing from C-2(Z) local sites symmetries to sigma(u psilon)(YZ) sites maintaining the same factor group C-2 upsilon. An assignm ent of the modes in the metastable phase is presented. Copyright (C) 2000 J ohn Whey & Sons, Ltd.