Diffuse phase transition and dielectric tunability of Ba(Zr yTi 1− y)O 3 relaxor ferroelectric ceramics

Abstract

Barium zirconate titanate Ba(Zr y Ti 1− y )O 3 (BZT, y = 0.2, 0.25, 0.30, 0.35) ceramics have been prepared by a sol–gel process. The temperature dependence of dielectric permittivity of the ceramics has been investigated. The results show that the phase transition temperature T C (or T m) is suppressed with increasing Zr content. The degree of diffuseness of the phase transition is more pronounced for higher Zr content, implying the existence of a composition-induced diffuse phase transition of the ceramics with 0.20 ⩽ y ⩽ 0.35. For BZT ceramics with y > 0.25, a relaxor ferroelectric characteristic is observed. High tunability and figure of merit are obtained in BZT compositions investigated, which imply that these ceramics are promising materials for tunable capacitor applications.