Structural, Dielectric, and Piezoelectric Properties of Mn-Doped BaTiO3–Bi(Mg1/2Ti1/2)O3–BiFeO3Ceramics

Abstract

Mn-doped (0.9-x)BaTiO3–0.1Bi(Mg1/2Ti1/2)O3–xBiFeO3 (x = 0.6, 0.7, and 0.8) ceramics were studied as candidate lead-free piezoelectric materials. The crystal structures were a pseudo-cubic perovskite at x = 0.6, a rhombohedral perovskite at x = 0.8, and a mixture of the pseudo-cubic and rhombohedral perovskite at x = 0.7. The Curie temperature was found to be 470 °C at x = 0.6 and more than 600 °C at x = 0.7 and 0.8. A strong pinning of domain walls was observed for high-field responses at x = 0.7 and 0.8, which was relaxed by high-temperature annealing and subsequent quenching. Piezoelectric properties increased with decreasing x, and the small-field piezoelectric constants d33 and d31 were 94 and 31 pC/N at x = 0.6, respectively.