Impact of Sr content on dielectric and electrical properties of pulsed laser ablated SrBi₂Ta₂O₉ thin films

Abstract

The ferroelectric properties of SrBi₂Ta₂O₉ thin films grown by laser ablation were investigated as a function of the Sr⁺² content in the films. Different target compositions were used to obtain films with different Sr⁺²/Ta⁺⁵ ratios. The initial composition was according to the stoichiometric composition (1/2), and the Sr⁺²/Ta⁺⁵ ratio was varied to 0.7/2.0. It was seen that the remanent polarization showed a consistent increase, as the film became more deficient of "Sr⁺²" up to a certain extent. Similarly, a decrease in the dielectric constant and the leakage current with the decrease of Sr⁺² in the film was observed. The dielectric transition temperature showed an increase with the reduction of Sr⁺² content and was seen to approach the bulk value.