Templated grain growth of 〈001〉-textured 0.675Pb(Mg _1/3Nb_2/3)O₃-0.325PbTiO₃ piezoelectric ceramics for magnetic field sensors

〈001〉-textured 0.675Pb(Mg_1/3Nb_2/3)O ₃-0.325PbTiO₃ (PMN-32.5PT) ceramics were synthesized through templated grain growth method using BaTiO₃ (BT) platelets as templates. A systematic investigation was conducted on delineating the texture development and microstructure evolution as a function of heat-treatment conditions. It was found that BT has very good stability in PbO-rich PMN-PT environment. A high texture degree of 90% was achieved using 5 vol% BT. Dielectric, ferroelectric, and piezoelectric properties were measured to understand the influence of sintering time, texture degree, and BT heterogeneity on the electrical characteristics. It was found that with increasing sintering time and texture degree, the piezoelectric constant d₃₃ increases while the dielectric constant decreases, resulting in about 50% improvement of g₃₃ as compared with random ceramics. Unipolar strain-field measurements of textured ceramics exhibited 0.27% strain at 30 kV/cm. The changes in large-signal response of textured ceramics were more obvious than small-signal measurement, indicating that 〈001〉 crystallographic texture enhances the piezoelectric response due to favorable domain configuration. Using the textured sample, a magnetoelectric laminate was fabricated and characterized for low magnetic-field sensitivity.