Effect of Sr substitution on the structural, dielectric and ferroelectric property of BaTiO.

We have performed a comprehensive study to explore the effect of Sr substitution on the structural and ferroelectric properties of BaTiO(BTO) with compositions BaSrTiOfor 0 ⩽⩽ 1. The room temperature structural investigation inferred that the samples with compositions> 0.30 has cubic phase instead of tetragonal as for pristine BTO. The temperature dependent dielectric studies illustrate that all well-known three structural phase transitions of BTO are coming closer to each other and the cubic phase is shifted towards lower temperature with increasing Sr content. The frequency dependent dielectric measurements show that there exists the mesoscopic subdomain, whose relaxation time decreases with increasing Sr concentration. The Sr substitution enhanced the ferroelectric properties and maximum remnant polarization at room temperature is observed for 20% Sr substituted sample. The frequency dependent dielectric measurements illustrate the relaxation which could be due to the mesoscopic subdomain, and its relaxation time decreases with increasing Sr concentration. The frequency dependentmeasurements at room temperature infer that for 30% Sr substituted sample, the ferroelectric domain switching is dominated by the rate of nucleation whereas in other compositions for< 0.3, it is governed by the domain wall speed. The Raman measurements infer the rearrangement of the domain configuration with Sr substitution. Modification in the intensity of the E(TO) and A(TO) Raman modes with electric field is also observed for 30% Sr substituted sample and the origin of this is also discussed.