The four stages of anneal induced changes in magnetic anisotropy and microwave resonance of FeCoBSi thin films

Amorphous Fe66Co17B16Si thin films deposited by DC magnetron sputtering have been annealed at various temperatures to investigate the microstructural, static and dynamic magnetization properties. Microwave permeability spectrum of the as-deposited films is intrinsically determined by the uniaxial in-plane anisotropy induced by an external magnetic field during deposition. After anneal, four stages are proposed to clarify the change of microwave permeability and its damping effect by means of surface morphology and magnetic property analysis. While the broadband ferromagnetic resonances for EMI shielding are achieved in our thin films, the complex process of grain and anisotropy refinements is revealed. Moreover, the effects of microstructural grain and macrostructural particle state on ferromagnetic resonance are discussed, to assist the future study and preparation of this kind of films.