Unusual Dielectric Behavior of La–Ti–Al–O Ceramics with Perovskite Structure

Abstract

Perovskite compounds, La_{(2+ x )/3}(Ti_{1- x} Al _x )O₃ with x ranging from 0.05 to 0.15, were prepared and the dielectric properties were investigated. Partial substitution of Al³⁺ for Ti⁴⁺ in La_2/3TiO₃ stabilizes the deficient perovskite structure with ordered A-site cation vacancy. Dielectric loss peaks show the existence of a relaxation process due to ionic motion related to the cation vacancy. High dielectric constants were obtained at lower frequency than the dielectric loss peak.