Short range polar state transitions and deviation from Rayleigh-type behaviour in Bi0.5Na0.5TiO3-based perovskites

Abstract

The polarization response of 0.95[0.94(Bi0.5Na(0.45)Li0.05)TiO3-0.06BaTiO3]-0.05CaTiO3ceramics was studied under weak applied cyclic electric fields with different amplitudes and frequency. The analysis of the polarization signals showed that in the ferroelectric phase the non-linearity is dominated by a Rayleigh-type dynamics, while in the ergodic relaxor phase the polarization response deviates from the Rayleigh-type behaviour due to the occurrence of short range electric field-induced transitions, evidenced by the presence of four distinct frequency independent current broad peaks in the current-electric field loops, which gives rise to a characteristic non-linear polarization-electric field loop with reduced hysteresis and weak frequency dependence.