Dielectric properties of PbFe_1/2Nb_1/2O₃ under pressure

Abstract

Temperature T (30-150°C) and pressure p (0-6 kbar) dependence of the permittivity ε and the spontaneous polarization Ps of PbFe_1/2Nb_1/2O₃ ceramics prepared by the use of alkoxides are presented. The ε has a broad maximum at the transition point Tt. The value of the exponent for the logarithmic plots of the reciprocal ε versus the reduced temperature above Tt is 2.0, which is almost independent of p. As p increases, the Tt decreases with dTtldp = -3.7K/kbar and the maximum value of ε decreases. The T and p dependence of e and Ps are explained by a phenomenological theory.