High-quality epitaxial Fe3Si films (10 0) were grown on the GaAs (10 0) surface using molecular beam epitaxy (MBE). High-resolution X-ray diffraction analysis using an X-ray energy of 12.38 keV from synchrotron radiation gave a narrow rocking curve of similar to 0.014 degrees for the Fe3Si (0 0 6) reflection, with a lattice mismatch between the film and GaAs of similar to 0.25% in the normal direction. Square-shaped M-H loops with a typical moment of 660 emu/cm(3) at 10 K and the easy axis along [10 0] were obtained for films grown at a substrate temperature (T-s) of 150 degrees C, and the M-H loops at low fields show fine features for films grown at a T-s of 200-300 degrees C. A two-step growth procedure with the initial growth at 150 degrees C and subsequently ramping to 250 degrees C was applied to minimize the interfacial reactions, thus to achieve abrupt interfaces. (c) 2006 Elsevier B.V. All rights reserved.