We have grown epitaxial thin films of Co3O4 on single-crystal MgO at similar to400degreesC by low-pressure thermal metalorganic chemical vapor deposition using cobalt(II) acetylacetonate as the precursor. X-ray phi-scan analysis shows that cube-on-cube epitaxy of Co3O4 occurs on MgO(1 0 0) in the temperature range similar to400-550degreesC. Films grown on MgO(1 0 0) at 410degreesC show a rocking curve FWHM of only 0.44degrees, despite a rather large lattice mismatch of 4.1%. This is interpreted to be due to the excellent match between the oxygen sublattices of Co3O4(1 0 0) and MgO(1 0 0). The strong epitaxy which occurs. leads to a low activation energy (E-d) for growth on MgO. Scanning electron microscopy analysis shows faceted grains characteristic of the cubic symmetry of Co3O4, the faceting being stronger at higher growth temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.