Abstract
An epitaxial L10 Fe/Pt thin film grown from the Fe/Pt multilayer with a composition of almost 1:1 was prepared successfully using ion beam sputtering deposition. To study the structural and magnetic transition from an Fe/Pt multilayer to an epitaxial FePt alloy thin film is the key point in this research. The Fe/Pt multilayer was grown at 100 °C and the multilayer structure was destroyed at an annealing temperature of 500 °C. When the annealing temperature reached 700 °C, the L10 ordered FePt film with growing along (001) orientation epitaxially was obtained. The order parameter reached above 0.95. In addition, c/a ratios of FePt films annealing at different temperatures were below 0.98. This result implies that the interdiffusion of Fe and Pt atoms during the annealing did not distorted the lattice structure too much. After the sample was annealed at 700 °C, the out-of-plane order parameter and squareness were close to 1 and magnetocrystalline anisotropy constant reached 3×107 erg/cc. It was indicated that the ordered FePt film has strong PMA effect. The ordered FePt film exhibited an out-of-plane coercivity of 1960 Oe after annealing at 600 °C, but it decreased to 1300 Oe after annealing at 700 °C. For the out-of-plane spin-to-orbital ratio, the Fe/Pt multilayer without annealing was 0.088; the Fe/Pt multilayer after annealing at 500 °C was 0.149; and the ordered FePt film after 700 °C was 0.174. It can be inferred that the higher order parameter, the stronger hybridization and spin-orbital coupling between Fe and Pt atoms occurs. Also, the higher orbital magnetic moment anisotropy implies the out-of-plane spin-to-orbital ratio becomes larger.