Heat Treatment Methods on Magnetic Properties and Microstructure of FePd Alloy Thin Films

Fe₅₂Pd₄₈ thin films with thickness of 10 nm were deposited on the glass substrate at room temperature and subsequently annealed at 600-900°C through three different heat treatment procedures: (A) furnace heating as well as quenching in the ice water; (B) furnace heating and then natural cooling in a furnace; and (C) rapid thermal annealing (RTA). The results show that the FePd films annealed at 800°C with procedures (A) and (B) present magnetic isotropy behaviors, whereas magnetic anisotropy is gradually switched to perpendicular with procedure (C). Further RTA of the FePd films with different temperatures, the film morphology is a continuous structure with well connected magnetic grains in as-deposited state, and it starts to agglomerate at 600°C and then turns into particle-like structure as the temperature is higher than 700°C. The magnetic behavior also switches from in-plane, through isotropy, and into out-of-plane directions. The heating rate and annealing temperature are the key effects on formation of Ll₀ FePd (001), but not for the cooling rate and annealing time. In this study, the RTA process is an effective way to induce the tensile stress in biaxial a and b, resulting the shrinkage along c-axis and ordered FePd Ll₀ (001) planes on glass. This paper shows a nonepitaxial method for Ll₀ FePd (001) orientation growth on amorphous glass substrates.