Effect of domain wall on the dielectric properties of the BaTiO 3/SrTiO 3 superlattices

Abstract

Based on a phenomenological thermodynamical theory, the effect of the domain wall on the dielectric properties of the polydomain BaTiO 3/SrTiO 3 superlattices with 180° electric domains in the BaTiO 3 layer is investigated. Theoretical analysis indicates that complete polarization suppression and the largest dielectric response take place at approximately 72% and 53% of the critical volume fraction of the SrTiO 3 layer for the domain wall energy parameter A=3×10 7 and 5×10 7, respectively. The dielectric properties largely depend on both the volume fraction of the SrTiO 3 layer and the domain wall energy parameter. Moreover, the gigantic dielectric response which occurs in single-domain BaTiO 3/SrTiO 3 superlattices cannot appear due to the 180° polydomain state in the BaTiO 3 layer, which is in agreement with the previous prediction. The high domain wall energy parameter results in the stabilization of the paraelectric state in the BaTiO 3 layer, however, the enhancement of the domain wall energy parameter within a certain scale increases the dielectric properties greatly.