Quick fabrication of appropriate morphology and composition CoFe films with desirable microwave properties

A methodology to quickly prepare CoFe nanofilms with large magnetic permeability and resonance frequency from simple salt solutions is demonstrated. As the microwave properties of thin films are largely determined by their surface morphology and composition, CoFe film with unique morphology and composition is proposed based on theoretical analysis and subsequently electrodeposited with suitable parameters. This approach reveals that Fe x Co 1 - x (0.3 < x < 0.5 in atomic ratio) films consisting of sub-30 nm spherical nanoparticles, even in the form of bigger aggregated-nanoparticles, usually show a low coercivity (≤4240 A · m −1 ), moderate magnetic anisotropy (2900–8580 A · m −1 ), and high magnetic moment (≥1.4 T), permeability (>200) as well as resonance frequency (>1 GHz). Further experimental analyses show root causes of the phenomena. This methodology also provides useful references to rapidly identify microwave properties of thin films from their surface morphologies and main electrodeposition parameters.