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

Perovskite compounds, La(2+ x )/3(Ti1- 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 La2/3TiO3 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.