Effect of La-substitution on the structure, dielectric and ferroelectric properties of Nb modified SrBi8Ti7O27 ceramics

Abstract

The effect of La substitution on the electrical properties of SrLaxBi8−xTi6.88Nb0.12O27 intergrowth Aurivillius phase ferroelectric ceramic was investigated. La content ‘x’ was ranging from 0.0 to 1.0 in a step of 0.2. The ceramic phase was synthesized through a modified oxalate route. X-ray diffraction was used to identify the phase and to investigate the change in lattice parameter and microstrain with the substitution. La-substitution does not affect the crystal structure of the intergrowth. Microstructural investigation revealed that the grain size of the ceramic decreases with La addition. The lattice parameters and orthorhombicity of intergrowth structure were found to decrease with increasing La substitution. The temperature dependence of dielectric behavior was investigated in the temperature range 30–700°C and the frequency of 100kHz. The remnant polarization 2Pr increased and the Curie temperature Tc decreased with the increase in the La substitution.