Growth and characterization of high-Curie temperature Pb(Lu1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 ternary single crystal by modified Bridgman technique

Abstract

A new relaxor-based ferroelectric ternary system Pb(Lu1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PLN–PMN–PT), with a combination of a high-Curie temperature system Pb(Lu1/2Nb1/2)O3–PbTiO3 (PLN–PT) and a high piezoelectricity system Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT), was investigated in this paper. Single crystal PLN–PMN–PT with dimensions of Φ20×45mm3 was grown successfully by the modified Bridgman technique for the first time. The studies of structure and composition of the as-grown crystal showed structural consistency but compositional deviation along the growth direction. The 〈001〉-oriented wafers of the PLN–PMN–PT single crystal showed excellent electrical properties at room temperature: ε33~4500, tanδ~0.5%, d33~2300pC/N. The crystal was found to exhibit high Curie temperature (TC~176°C), rhombohedral–tetragonal phase transition temperature (TRT~108°C) and coercive field (EC~8.1kV/cm), superior to those of PMN–0.3PT single crystal. Studies of temperature dependence ferroelectric properties showed that high values of k33 and d33 could be maintained up to the TRT. These results showed that PLN–PMN–PT piezoelectric single crystal has a higher Curie temperature and coercive field with excellent electrical properties, making the crystal a promising candidate for high-power transducer applications in a broad temperature range.