Relaxational polarization dynamics in soft ferroelectrics

Abstract

Investigations of the frequency dependence of the $\mathrm{P–E}$ (polarization versus field) and $\mathrm{\epsilon –E}$ (strain versus field) behavior have been performed on soft ${\mathrm{0.7Pb(Mg}}_{\mathrm{1/3}}{\mathrm{Nb}}_{\mathrm{2/3}}{\mathrm{)O}}_{\mathrm{3}}{\mathrm{–0.3PbTiO}}_{\mathrm{3}}$ polycrystalline ferroelectrics at various maximum field strengths below and above that of the coercive field ${\mathrm{(E}}_c\mathrm{).}$ For ${\mathrm{E<E}}_c,$ a strong relaxational polarization was observed. At low frequencies, in this field range, $\mathrm{P–E}$ curves indicative of polarization switching were observed with an apparent remanence, however at higher frequencies near-linear $\mathrm{P–E}$ behavior was found.