Dielectric, structural and Raman studies on (Na_0.5Bi_0.5TiO₃)_{(1 −<i>x</i>)}(BiCrO₃)_<i>x</i>ceramic

Abstract

Dielectric, structural and Raman investigations were carried out on a perovskite-based solid solution of (NBT)((1 - x))(BiCrO(3))(x) (x = 0.00, 0.05, 0.10 and 0.15). The crystal structure is rhombohedral, R3c, for these compositions and the anti-phase (a( - ) a( - ) a( - )) tilt angle decreases with increasing BiCrO(3) content. The temperature and frequency dependent dielectric measurements show that the phase transition temperatures T(d) and T(R - T) decrease, while T(m) increases, almost linearly with an increase in BiCrO(3) content. An anomalous increase in the relative dielectric permittivity is observed at higher temperature (T > T(d)) and higher BiCrO(3) content. However, at lower temperature (T < T(d)) the dielectric permittivity decreases with an increase in BiCrO(3) content. These effects are explained on the basis of the dynamics of oxygen defects produced due to charge compensation. The defect related bands are observed in the Raman spectra of (NBT)((1 - x))(BiCrO(3))(x).