Microwave absorption of ε-Fe_2O_3 precipitated from sputter deposited Fe-Si-O amorphous thin film by thermal annealing

摘要

Granular magnetic thin films were prepared by thermal annealing of rf-sputter-deposited Fe-Si-O amorphous films. The particle size of the precipitated Fe_2O_3 was controlled to obtain a pure e-phase by adjusting the target chemical composition to an atomic ratio SiO_2/Fe_2O_3=2 and annealing for 1 to 3 h at 900 C. For a film annealed for 100 min, an almost symmetrical ferromagnetic resonance signal was observed, with no evidence of residual ferric ions in the amorphous silica matrix.