DIELECTRIC-DISPERSION ASSOCIATED WITH THE DC-ELECTRIC-FIELD-ENFORCED FERROELECTRIC PHASE-TRANSITION IN THE PRESSURE-INDUCED ANTIFERROELECTRIC CSH2PO4

The dc-electric-field dependence of the dielectric properties (complex permittivity and relaxation time) of the antiferroelectric CsH2PO4 was investigated at 4.5 kbar under various frequencies. The strong dielectric dispersion along the b axis associated with the field-enforced ferroelectric phase transition was observed. The slowing down of the relaxation time toward a critical electric field Ecr, which induces the forced transition to the ferroelectric phase, was observed. Although the dielectric dispersion strength is zero without an applied dc field Ed, with an increase in Ed it increases gradually, rapidly near Ecr in the antiferroelectric phase and decreases monotonically in the ferroelectric phase. The relaxation time of the order of 10-5 s near Ecr in the antiferroelectric phase for the field-enforced transition is extremely low in contrast to that of the order of 10-8 s near the transition temperature in the paraelectric phase for the paraelectric-ferroelectric phase transition. © 1990 The American Physical Society.