The study of dielectric diffuseness in the Ba(Mg1/3Nb2/3)O-3-BaTiO3 ceramic system

摘要

The dielectric properties of Ba(Mg1/3Nb2/3) O-3 (BMN)-substituted BaTiO3 (BT) (xBMN -(100 - x) BT) ceramics, where x = 0 - 5 mol%, were prepared by a high-temperature solid-state reaction technique. It was found that the substitution of Mg2+ and Nb5+ at the Ti-site of the BMN - BT ceramics caused compositional inhomogeneity, leading to a diffuse phase transition (DPT). Discontinuous grain growth accompanied with excellent dielectric diffuseness was found in 3 - 5 mol% BMN specimens. The maximum solubility limit of Mg/Nb substitution was assumed to be between 3 < x < 4 mol% BMN. A dielectric study of these compounds as a function of temperature suggested that, for the ceramics with x > 2 mol%, the maximum dielectric constant decreased and the Curie temperature shifted downwards on the lower temperature side.