Magnetite thin films have been grown onto (10 0)Si, (10 0)GaAs and (0 0 0 1)Al2O3, at substrate temperatures varying from 473 to 673 K, by UV pulsed laser ablation of Fe3O4 targets in reactive atmospheres of O-2 and At, at working pressure of 8 x 10(-2) Pa. The influence of the substrate on stoichiometry, microstructure and the magnetic properties has been studied by X-ray diffraction (XRD), conversion electron Mossbauer spectroscopy (CEMS) and magnetic measurements. Magnetite crystallites, with stoichiometry varying from Fe2.95O4 to Fe2.99O4, are randomly oriented for (10 0)GaAs and (10 0)Si substrates and exhibit (1 1 1) texture if grown onto (0 0 0 1)Al2O3. Interfacial Fe 3 ' diffusion, which is virtually absent for (10 0)Si substrates, was found for both (0 0 0 1)Al2O3 and (10 0)GaAs, with some deleterious effect on the subsequent microstructure and magnetic behaviour. (c) 2007 Elsevier B.V. All rights reserved.