Bismuth nickel niobate with small negative temperature coefficients of dielectric constant

Abstract

Bismuth nickel niobate was prepared by conventional solid state reaction technique. Dense ceramic body was obtained at low sintering temperatures. In Bi2O3-NiO-Nb2O5 ternary oxide system, the structure and dielectric properties of several compositions along the selected NiO:Nb2O5=1∶1 composition line, have been investigated by X-ray diffraction analyses and temperature dependences of dielectric constant and loss factor. Cubic pyrochlore, tetragonal pyrochlore, and other unknown phases occur in the concerned compositions. Small negative temperature coefficient of dielectric constant has been reported. The low temperature dielectric relaxation, common to almost all compositions, has been curve fitted according to the ε-T empirical equation of ferroelectrics. The index factor is 1.4 or so, corresponding to the ferroelectric relaxation.