LaFeO3 (LFO) thin films were epitaxially grown on MgO(0 0 1) single-crystal substrates by RF magnetron sputtering. The epitaxial LFO films were grown with a cube-on-cube relationship and pseudo-cubic crystal when the substrate temperature was above 500degreesC, lower than any temperature reported before. The crystalline quality and root mean square surface roughness of the epitaxial LFO films were greatly improved by increasing the substrate temperature and the working pressure, of which the optimum values were 0.97degreesC and 0.58 nm, respectively. The X-ray photoelectron spectroscopy measurements showed that the La and Fe ions were trivalent when the epitaxial LFO films were grown at 500degreesC. The lower crystalline quality of the epitaxial films resulted primarily in the formation of a high lattice mismatch and a difference in the crystal structures between the films and substrates. (C) 2003 Elsevier B.V. All rights reserved.