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 μi larger than 100, the saturation magnetization 4πMs and the in-plane uniaxial anisotropy field Hk increase as the magnetic FeCoSi layer thickness d is increased from 5.5 to 20.5 A. As a consequence, the ferromagnetic resonance frequencies fr of the films increase from 2.0 to 3.9 GHz. The combination of high fr and large μi 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.