Top-seeded solution growth and characterization of rhombohedral PMN–30PT piezoelectric single crystals

Abstract Piezoelectric single crystals from 70Pb(Mg 1/3 Nb 2/3 )O 3 –30PbTiO 3 solid solution were grown by a top-seeded solution growth method that prevented phase segregation and promoted (0 0 1) growth. Rhombohedral symmetry was confirmed by polarized light microscopy and the dielectric, piezo- and ferro-electric properties were characterized. A dispersive maximum of dielectric permittivity appears around T C = 125 °C, which slightly shifts towards higher temperatures with increasing frequency, indicating weak relaxor behaviour. Rhombohedral–tetragonal phase transition was detected at 105 °C. This temperature is higher than the depoling temperature of the morphotropic phase boundary compositions (50–80 °C), thus extending the upper limit of the application temperature for electromechanical transducers. The piezoelectric coefficient ( d 33 ) was found to be 1240 pC N −1 , with a strain level reaching 0.12% at an electric field of 12 kV cm −1 . The longitudinal electromechanical coupling factor k 33 reaches 85%, which persists upon heating up to 100 °C.