Growth temperature dependence of long-range alloy order and magnetic properties of epitaxial FexPt1-x (x similar or equal to 0.5) films

The structural and magnetic properties of 1000-Angstrom-thick epitaxial FexPt1-x(001) alloy films, grown by molecular beam epitaxy with x similar or equal to 0.5, have been studied as a function of growth temperature, X-ray diffraction analysis showed that the long-range order parameter increased from near Zero for films grown at 100 degrees C to a maximum of 0.93 in films grown at 500 degrees C. Over this range the magnetic easy axis changed from in-plane to perpendicular and the polar Kerr rotation increased strongly. Spontaneous long-range ordering in these films has an activation energy similar to 0.2 eV, consistent with an energy barrier for surface and step down diffusion. (C) 1996 American Institute of Physics.