Artificial fabrication and characterization of L10-ordered FeNi thin films

L1₀-FeNi, showing uniaxial magnetic anisotropy (K_u) of 1.3×10⁷ erg/cm³ in a bulk sample, is promising as a “rare metal-free” high K_u material. It is known that iron meteorites contain the L1₀-FeNi phase, what is called “tetrataenite”, which reveals unique magnetic properties different from usual Fe-Ni alloys. However, the artificial fabrication of L1₀-FeNi is difficult because the order-disorder transformation temperature is low (~320C), and below this temperature the atomic diffusion is extremely slow. In this study, we have tried to fabricate L1₀-FeNi thin films with high K_u by two methods: molecular beam epitaxy (MBE) and sputtering.