Enhanced piezoelectricity due to phase transitions and coexistence in 0.7Pb(Mg_1/3Nb_2/3)-0.3PbTiO₃ single crystal

Using scanning electron acoustic microscopy, the spatial distribution of different phases and inhomogeneous electric-field-induced phase transitions have been observed in 0.7Pb(Mg_1/3Nb_2/3)-0.3PbTiO₃ single crystals. The experimental results initially confirm that electric-field-induced phase transitions result in the enhanced piezoelectric properties in relaxor-based ferroelectrics with morphotropic phase boundary compositions. It is also revealed that the regions where phases coexist initially have the highest local piezoelectric property when increasing, decreasing and removing the applied electric-field. Therefore, it is suggested that increasing the volume fraction of the phase coexistence region is a feasible way to further enhance the overall piezoelectricity of PMNT single crystals.