Structural characterization of sputter-deposited Ba 0.48Sr 0.52TiO 3/LaNiO 3 artificial superlattice structure by X-ray reflectivity and diffraction

Abstract

Ba 0.48Sr 0.52TiO 3/LaNiO 3 artificial superlattices with a symmetric sublayer structure were successfully fabricated on Nb-doped SrTiO 3 (001) single-crystalline substrate with rf magnetron sputtering. X-ray reflectivity and high-resolution diffraction measurements were employed to characterize the microstructure of these films. Formation of a superlattice structure was confirmed from the appearance of Bragg peaks separated by Kiessig fringes in X-ray reflectivity curves and a diffraction pattern. The fitted result from X-ray reflectivity curves shows that the densities of the Ba 0.48Sr 0.52TiO 3 and LaNiO 3 sublayers were slightly less than their bulk values. The appearance of discernible satellite peaks beside the main peak of the crystal truncation rod observed for deposited films clearly demonstrates that a well-defined superlattice structure can be formed with rf sputtering. The artificial Ba 0.48Sr 0.52TiO 3/LaNiO 3 superlattices exhibit a large dielectric constant and a small dielectric loss. The smaller is the stacking periodicity of superlattices, the larger is the dielectric constant and dielectric loss.