Relaxor behavior in BaTiO3

Abstract

BaTiO 3 shows relaxation effects when minute concentrations of Bi+3 and Fe+3 are added in varying molar ratios. Addition of Bi+3 at the A site reduces the transition maximum (Tm), whereas Fe+3 addition at the B site reduces the value of dielectric constant. Doping of Bi+3 and Fe+3 in equimolar ratios shows a positive shift in relaxation, while excess addition of either of the dopants produces a negative shift in the transition maximum with increasing frequency. Relaxation effects follow the Vogel–Fulcher law for spin glasses. The dielectric loss also shows relaxation effects.