An artificial superlattice of BaTiO3/LaNiO3 (BTO/LNO) was grown epitaxially on an Nb-doped SrTiO3 (001) single-crystalline substrate with a dual-gun rf magnetron sputtering system. The structural characteristics of the superlattice films were studied mainly by X-ray reflectivity. Formation of a superlattice structure was confirmed from the appearance of Bragg peaks separated by Kiessig fringes in X-ray reflectivity curves and a crystal truncation rod (CTR) spectrum. The surface and interfacial roughness of the superlattice were derived from the fitted curves for specular reflectivity. A conformal relationship between consecutive BTO and LNO layers was observed from off-specular scattering. According to the fitted results and atomic-force microscopy images, the evolution of surface structure follows the Stranski-Krastanov (S-K) growth mode, in which the surface roughness increased with the thickening of sublayers. (C) 2004 Elsevier B.V. All rights reserved.