Simulation of current-jumping phenomena in PbTiO3-Pb(Sc1/2Nb1/2)O3 system piezoelectric ceramics

The nonlinear piezoelectric phenomena were investigated in PbTiO3-Pb(Sc1/2Nb1/2)O-3 (PT-PSN) system ceramics, which is reported to be the ferroelectric relaxer material having a large d(31) constant. The calculated values for current-jumping and resonance-frequency change obtained using our old simulation, in which only xi(D31) is used as a nonlinear piezoelectric coefficient of third-higher term for the electrical field, agreed well with the measured values in the region of tetragonal phase. On the other hand, in the rhombohedral region, the calculated values did not agree with the measured values. This disagreement was resolved by reflecting the contribution of a new nonlinear piezoelectric coefficient of third-higher term for mechanical stress, xi(D31), in the calculation. Furthermore, a nonlinear loss term was incorporated into the calculation by handing xi(D31) as a complex number. The use of complex xi(D31) enabled the exact prediction of the drop point of the current, which has never been possible. (C) 2008 The Ceramic Society of Japan. All rights reserved.