Structural and dielectric properties of Ba5 R NiNb9O30 (R=La, Nd and Sm) ceramics

Abstract

Three novel Ba5RNiNb9O30 (R=La, Nd and Sm) ceramics were prepared and characterized in the BaO−R2O3−NiO−Nb2O5 system. All three compounds are paraelectric phases adopting the filled tetragonal tungsten bronze (TB) structure at room temperature. At 1MHz, Ba5RNiNb9O30 ceramics have a high dielectric constants in the range 193–245.3, a low dielectric loss in range 0.0059–0.0087, and the temperature coefficients of the dielectric constant (τe) in the range −1140- −1310×10−6·°C−1. Their temperature coefficients of the dielectric constant are significantly reduced compared to those of Ba5RTi3Ta7O30 (R=La, Nd, Sm) ceramics.