Tuning the Magnetic Properties of Cobalt-Based Metallic Glass Nanocomposites

Abstract

Temperature-induced variation in magnetic properties for cobalt-based metallic glass was investigated. The formation of metastable nanocrystalline phases prior to complete devitrification and their effect on magnetic properties for Co72B19.2Si4.8Cr4 metallic glass was studied. The nature, shape, and distribution of the intermediate nanocrystalline phases were characterized using transmission electron microscopy and x-ray diffraction. A drastic change in magnetic properties was found in going from a fully amorphous state to different stages of nanocrystallization. The coercivity changes from amorphous soft magnetic state (H-c similar to 0.12 Oe) to a nanocrystalline-dispersed hard magnetic state (H-c similar to 187 Oe), with no significant change in saturation magnetization. This suggests potential use in futuristic magnetic switches, fluxgate sensors, and electromagnetic shielding devices.