Abstract
Polarization and strain induced by unipolar electric field (P\ulcorner, S\ulcorner), those induced by bipolar electric field (P, S) and remanent polarization (P\ulcorner) were investigated in 0.9Pb(Mg\ulcornerNb\ulcorner)O$_3$-$0.1PbTiO_3$relaxor ferroelectric ceramics in the temperature range of $-50^{\circ}C$~$90^{\circ}C$. From the temperature dependence of polarization and strain, the transition from predominantly paraelectric (electrostrictive) to partially ferroelectric (piezoelectric) is visualized. Under the given temperature, the P\ulcorner/P\ulcorner is always larger than the S\ulcorner/S\ulcorner and the difference between them becomes larger ass the temperature decrease. The S\ulcorner/P\ulcorner increases as the temperature decreased below phase transition temperature. It was suggested that these experimental results might be explained with a simple rigid ion model concentrating on BO\ulcorner octahedron.
