Dielectric properties of Ba5MTi3A7O30 [M = Ce, Pr, Nd, Sm, Gd, Dy and Bi; A = Nb, Ta] ceramics

Polycrystalline Ba5MTi3A7O30 [M = Ce, Pr, Nd, Sm, Gd, Dy and Bi; A = Nb, Ta] ceramics were prepared as single-phase materials through conventional solid-state ceramic route. The structure was studied by X-ray diffraction method and dielectric properties were measured in the frequency range 100 Hz–1 MHz from room temperature to 250 °C. At 1 MHz their dielectric constant ( ε r ) varies from 164 to 887 and loss tangent (tan δ) from 10−3 to 10−2. The study indicates a ferroelectric-paraelectric diffuse phase transition in Ba5MTi3Nb7O30 [M = Ce, Pr, Nd, Sm, Gd, Dy and Bi] ceramics above room temperature. But Ba5MTi3Ta7O30 [M = Ce, Pr, Nd, Sm, Gd, Dy and Bi] ceramics show linear variation of ε r at and above room temperature. The measured dielectric properties indicate that these materials are possible candidates for the fabrication of discrete multilayer capacitors in microelectronic technology.