High-field electromechanical properties of some Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃-based relaxors

Abstract

Abstract Electrostrictive ceramics in the (1–x)[(1–y)Pb(Mg1/3Nb2/3)O3-yPbTiO3]-xMeTiO3 system, where Me is Sr or Ba, have discriminating properties for a variety of electromechanical applications. Electrostrictors fill niches that depend on a large mechanical energy density (24 kJ/m3), large (<1000 ppm) field-induced strain, high (>600 pC/N) effective d33, and low electromechanical hysteresis (<2%). As relaxor ceramics, the weak-field material behavior is dependent on both temperature and frequency. Two groups of materials with differing microstructures were examined to assess the relaxor nature of the high-field electromechanical properties. Both weak and high-field measurements were used to clarify the transition behavior and assess the engineering utility of the two material types. Although these two groups of materials were synthesized from identical starting materials, major differences were obtained in terms of grain size, relative permittivity, dielectric aging, and strain and average hysteresis.