Peculiar Hysteresis Loop of Pb(Mn1/3Nb2/3)O3–Pb(Ti, Zr)O3 Ceramics

The P–E curves of Pb[Zr0.52Ti0.48(Mn1/3Nb2/3)]O3 ceramic with different sintering temperatures and variations of strontium (Sr) compositions have been investigated. It has been demonstrated that the polarization–field hysteresis curves show “pinched” shapes instead of the normal square-like P–E loops. In this paper we present the temperature dependence of the P–E curves for the ceramic with different firing temperatures and Sr dopants and show that the critical transitional temperature at which disappearance of the “pinched” shape occurs is highly dependent on the tetragonality (c/a ratio). In the meantime, the peculiar hysteresis loops are assumed to be the result of the pinning effect of the defect dipoles, which are slowly oriented antiparallel to the poling direction, and are finally broken down by the thermal activation.