Magnetostriction and effective magnetic anisotropy of Co-contained Finemet nanocrystalline alloys

Abstract

The microstructure and magnetic properties of Co-contained Finemet nanocrystalline alloys were investigated. By contrasting with Finemet, the Co-contained Finemet nanocrystalline alloys have a broad temperature range for precipitating a single α-FeCo crystalline phrase and a relatively higher Curie temperature of amorphous phase. After full nanocrystallization they exhibit improved high-temperature soft magnetic properties. However the room-temperature permeability of Co-contained Finemet was obviously lower than that of Finemet. For clarifying the reason, the effective magnetic anisotropy ⟨K⟩ and the saturation magnetostriction λs were measured, respectively, and the ⟨K⟩ of Co-contained Finemet is about 100–137 J/m3, which is the same order of magnitude as Finemet, but the λs of Co-contained Finemet-type alloy is much higher than that of Finemet which results in a relatively lower permeability.