High-frequency properties of discontinuous FeCoSi/native-oxide multilayer films

Discontinuous [FeCoSi ( d)/native-oxide] 50 multilayer films were fabricated by DC magnetron sputtering without any post-deposition treatment. The films exhibit good soft magnetic properties with initial permeability μ i larger than 100, the saturation magnetization 4 πM s and the in-plane uniaxial anisotropy field H k increase as the magnetic FeCoSi layer thickness d is increased from 5.5 to 20.5 Å. As a consequence, the ferromagnetic resonance frequencies f r of the films increase from 2.0 to 3.9 GHz. The combination of high f r and large μ i makes these films potential candidates for magnetic devices applied in the high-frequency range. The origin of the excellent high-frequency properties in discontinuous FeCoSi/native-oxide multilayer films is discussed.