Structural, Dielectric, and Piezoelectric Properties of Mn-Doped BaTiO₃–Bi(Mg_1/2Ti_1/2)O₃–BiFeO₃ Ceramics

Abstract

Mn-doped (0.9- x )BaTiO 3 –0.1Bi(Mg 1/2 Ti 1/2 )O 3 – x BiFeO 3 ( 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 d 33 and d 31 were 94 and 31 pC/N at x = 0.6, respectively.