Growth temperature dependence of long‐range alloy order and magnetic properties of epitaxial FexPt1−x (x≂0.5) films

The structural and magnetic properties of 1000‐A‐thick epitaxial FexPt1−x(001) alloy films, grown by molecular beam epitaxy with x≂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 °C to a maximum of 0.93 in films grown at 500 °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 ∼0.2 eV, consistent with an energy barrier for surface and step down diffusion.