Bi0.8La0.2FeO3 thin films on Pt/TiO2/SiO2/Si substrates at various substrate temperatures from 500 degrees C to 750 degrees C are prepared by pulsed laser deposition, and their microstructures and ferroelectric/magnetic properties are carefully investigated using various techniques. It is observed that the crystallographic orientation and Fe-ion valence state depend significantly on the substrate temperature, which consequently influences considerably on the ferroelectric and magnetic properties of the thin films. A considerable improvement of the ferroelectric and magnetic properties of the thin films can be achieved by optimizing the substrate temperature for deposition. (C) 2007 Elsevier B.V. All rights reserved.