Dielectric and Piezoelectric Properties in the BiScO3–PbTiO3–PbO·SnO2 Ternary System

Abstract

The effect of Sn substitution on the dielectric and piezoelectric properties of BiScO3–PbTiO3 was investigated in the ternary system, (1-x){(1-y)BiScO3–yPbO·SnO2}–xPbTiO3 (x=0.43–0.63, y=0.25–0.75). The ferroelectric phase transition temperature near morphotropic phase boundary (MPB) decreased with increasing Sn content from 450°C (x, y=0.64, 0) down to ∼250°C for the composition with x, y=0.46, 0.75. Piezoelectric activity (d33=460–465 and kp=0.54) in Sn-substituted MPBs remained at similar levels to the pure 0.46BiScO3–0.64PbTiO3 MPB, with Sn content of up to y=0.5. However, further Sn-additions lead to decreased electromechanical performance and the formation of secondary phases such as SnO2. Broad temperature dependence of the permittivity near the ferroelectric phase transition was assessed by a diffuseness parameter δ, which generally decreased with firing temperature in the range of 1050–1250°C. The temperature of the permittivity maximum (Tmax) increased with measuring frequency, a characteristic consistent with relaxor ferroelectric materials.