Microstructure and magnetic properties of self-assembled FePd-SiN films

Self-assembled FePd-SiN nanocomposite films were fabricated successfully by direct current (dc) reactive magnetron sputtering and then followed by vacuum annealing. The effects of Si-N matrix and annealing temperature on the structure and magnetic properties were investigated. The as-deposited films show typical magnetically soft behavior with face-centered cubic (fcc) FePd phase, which transforms into the face centered tetragonal (fct) structure after thermal annealing at 600 A degrees C. The grain size of FePd increased with the annealing temperature but decreased with increasing Si-N content. Increasing Si-N content forms SiN-rich amorphous phase distributed between the FePd nanograins, which inhibits the growth of the FePd particles. The fct-FePd films annealed at 700 A degrees C exhibited moderate coercivity, up to 2330 Oe at room temperature. These FePd-SiN films have shown promise for high-density magnetic recording medium.