Microscopic Structure and Magnetic Properties in State of FeMn Alloy Added Bi

Fe-Mn-Bi films were formed by electron beam vacuum evaporation, and then oxidized by annealing in an oxygen atmosphere to obtain ferromagnetic oxide films. The film composition profiles and magnetic properties were then investigated. Depth profiles as determined by AES indicated a uniform film composition, but X-ray diffraction indicated the formation of FeMnBiO 4 upon annealing. From the annealing temperature dependences of the saturated magnetization and coercive force, a magnetic transformation point exists near 300°C, a result confirmed by separate resistivity measurements.