High Electrical Resistivity and Soft Magnetic Properties of Fe-Mg-O Thin Films

The soft magnetic properties and electrical resistivity of Fe-Mg-O films prepared by an rf magnetron sputtering technique were studied for high-frequency (e.g., 100 MHz) soft magnetic materials. Soft magnetic Fe-Mg-O films have a heterogeneous structure containing nanometer sized Fe-grains.A high saturation magnetization of 10-18 kG and a high electrical resistivity of 100-1000 μΩcm were achieved for Fe-Mg-O films with an Fe content of 40 to 80 at%. The relative permeability of an Fe60Mg17O23 film was about 2000, and was almost constant up to 200 MHz.