High Curie-temperature (TC) piezo-/ferroelectric single crystals with bismuth-based complex perovskites: Growth, structures and properties

Complex perovskite solid solutions based on Bi(B′B″)O3-PbTiO3 are potentially interesting ferroelectric and piezoelectric materials with high Curie temperature (TC). In this work, large-size (1-x)Bi(Zn1/2Ti1/2)O3-xPbTiO3 (BZT-PT), and (1-x)Bi(Zn2/3Nb1/3)O3-xPbTiO3 (BZN-PT) single crystals have been successfully grown by the high-temperature solution growth method and the top-cooled solution growth method. A comparative study of the (001)-oriented BZT-PT and BZN-PT crystals is carried out and significant differences are found in their structures and physical properties which are characterized by various techniques. The crystal structures of both crystals are refined to be of tetragonal symmetry by means of powder X-ray diffraction, but their local structures exhibit remarkable differences in terms of cationic displacements. The TC is determined to be around 572 °C and 424 °C for the BZT-PT and BZN-PT single crystals, respectively. The ferroic domain structures examined by polarized light microscopy based on optical crystallography are found to be different in the BZT-PT and BZN-PT crystals. The effects of domain structures on the different ferroelectric behaviors are investigated. The high TC and large coercive electric field, as well as the high remanent polarization of the BZT-PT and BZN-PT single crystals make them promising candidates for applications in high-power electromechanical transducers that can be operated in a wide temperature range.

Single crystals of complex perovskite Bi(Zn1/2Ti1/2)O3-PbTiO3 (BZT-PT) and Bi(Zn2/3Nb1/3)O3-PbTiO3 (BZN-PT) systems were successfully grown. A comparative and comprehensive study on the crystal structure, domain structure, composition segregation, and dielectric, ferroelectric and piezoelectric properties of these two types of crystals was carried out. The high Curie temperature (TC), large coercive electric field and high remanent polarization characterize the enhanced properties of these solid solution crystals which are potentially useful for high temperature and high power electromechanical transducer applications.117