Soft magnetic nanocomposite CoZrTaB-SiO2 thin films for high-frequency applications

With increasing switching frequencies for passive components in power supplies, there lies a demand for materials that exhibit excellent soft magnetic properties at high frequencies. Electrical resistivity is of particular importance, as a high value is of significant importance in suppressing eddy current loss. The present work is focused on improving material with ultra-soft magnetic properties at high working frequencies by making nanocomposite CoZrTaB-SiO2 thin films using co-sputtering. The films show an increasing trend of resistivity with SiO2 incorporation, attributed to the high degree of electron scattering based on a metal-insulator-metal network. The ultra-low coercivity (H-c similar to 0.1Oe) and enhanced anisotropic field (H-k similar to 42Oe) of films were correlated to the ferromagnetic exchange coupling, which were significantly affected by a small concentration of SiO2. Relatively high permeability, ultra-low loss response, and high ferromagnetic resonance frequency make this material a promising candidate for replacing conventional magnetic cores in passives, in addition to noise suppression applications.