Effects of Sr substitution on dielectric characteristics in Bi1.5ZnNb1.5O7 ceramics

Modification of dielectric characteristics of Bi1.5ZnNb1.5O7 pyrochlore was performed by Sr substitution for Zn in A-site together with the phase evolution. In general, the ceramics prepared by solid-state reaction are multiphase materials. However, single phase specimens having cubic pyrochlore structure could be obtained in the vicinity of Sr=0.1. The temperature coefficient of the dielectric constant (αc) of Bi1.5ZnNb1.5O7 increased remarkably by Sr substitution, but dielectric constant varied slightly while the dielectric loss increased steadily. Ceramics of those series have dielectric properties of high ε (>145) and low temperature coefficient. The A-site cation substitution caused a very slight change in dielectric constant, suggesting little effect of the substitution on the ionic polarization of the pyrochlore structure.