Magnetic Properties of Fe-M-O (M=Zr, Hf) Films with High Resistivity

The magnetic properties of Fe-M-O (M=Zr, Hf≫ films with high electrical resistivity, prepared by the rf magnetron sputtering technique in an Ar+O2 atmosphere, were investigated. In the as-deposited state, low coercivities (Hc) in the range 30 to 100 A/m were obtained for Fe-Hf-O, and 160 to 240 A/m for Fe-Zr-O, in the composition range characterized by an O/M ratio of between 3 and 4. After annealing under optimum conditions in an external field of 160 kA/m, the results obtained for Fe54.9Hf11O34.1 and Fe65.3Zr8.9O25.8 included a saturation magnetization (Bs) of 1.2 T, an Hc of 64 A/m, and a ¿ at 100 MHz of 1600 for the former, and a Bs of 1.3 T, Hc of 73 A/m and ¿ at 100 MHz of 1000 for the latter. Further, the electrical resistivities of the films were much higher than those of known metallic soft magnetic films.