High-Frequency Magnetic Properties Fe–Hf–B–O Ribbons With Chromium Additive

Large permeability, low core loss, and high-saturation magnetization are the important parameters for the applications of soft magnetic materials in high-frequency power electronics. By introducing Cr as oxygen-retardant agent in FeHfB melt-spun ribbons and annealing samples in an ultralow partial oxygen pressure environment, we have successfully prevented oxidation of Fe in forming FeCrHfO composites with exchange coupled Fe nanograins. A coercivity of 0.56 Oe and a saturation magnetic flux density of 1.33 T have been achieved in exchange coupled samples. The samples show a high permeability of 250 at 10 MHz.