Structural characterisation of sol-gel SrBi2Nb2O9 thin film deposited on (001) SrTiO3 single crystal

Abstract SrBi 2 Nb 2 O 9 (SBN) thin films with thickness close to 30 nm were deposited on single crystalline (001) SrTiO 3 (ST) substrate by sol–gel spin-coating. After deposition, the films annealed for 30 min at several temperatures (500, 550, 600, 650 and 700 °C) were studied by X-ray diffraction using a home-made diffractometer operating in asymmetric reflection geometry. Crystallisation of the precursor as pure SrBi 2 Nb 2 O 9 occurs between 500 and 550°C. The normal orientation of the film occurs at 550°C, i.e. at the very beginning of the crystallisation process. Rocking curves of (0010) lines show their full widths at half maximum (FWHM) decrease from 2·5° (550°C) to 1·8° (700°C), indicating that the small remaining disorientation decreases with increasing annealing temperature. A full φ-scan study of selected reflections showed that the film is heteroepitaxied on the substrate such as (001) SBN //(001) ST and [100] SBN //[110] ST .