Structure and magnetic properties of annealed metastable FeAg/Pt films

摘要

FeAg and FeAg/Pt films were prepared by dc magnetron sputtering at room temperature. The effects of Ag volume fraction in FeAg films and postannealing temperature and time on structure and magnetic properties of FeAg and FeAg/Pt films have been investigated. The results show that the as-deposited FeAg films are metastable. After annealing at 300°C, the phase separation of metastable FeAg films happened and the highest coercivity is obtained in Fe₅₀Ag₅₀/Pt film. With increasing annealing temperature, the ordering and the magnetic properties of the Fe₅₀Ag₅₀/Pt films were improved. When the Fe₅₀Ag₅₀/Pt films are annealed at 600°C for different annealing times, a long annealing time enhances the ordering of the metastable Fe₅₀Ag₅₀/Pt films and affects the orientation development. When the films are annealed for a long time, the grain size and the magnetic domain size also increase, which lead to an increase of correlation length due to the growth of FePt grains.