Crystallization Behavior of Sol–Gel‐Derived Strontium Barium Niobate Thin Films

Abstract

The crystallization of sol–gel‐derived strontium barium niobate (SBN) thin films on various substrates is enhanced by a two‐step heating process. Also, SBN films with c ‐axis preferred orientation are obtained on MgO (100) substrates. The crystallized phase and the degree of orientation are dependent on crystallization temperature and film composition. The crystallization temperature required to form a single tetragonal tungsten bronze (TTB) SBN phase increases with an increase of Sr content due to the distorted SBN structure. However, in the case of the film on MgO substrate, the oriented crystallization which forms the single tetragonal phase occurs at a lower crystallization temperature than those of polycrystalline films because of lattice matching between the film and the substrate. Its optical and ferroelectric properties were also investigated. They vary depending on film composition, due to the effect of the distorted SBN structure.