Impact of Ion-Irradiation upon Microstructure and Magnetic Properties of NANOPERM-Type Fe₈₁Mo₈Cu₁B₁₀ Metallic Glass

Microstructure and soft magnetic properties of the Fe₈₁Mo₈Cu₁B₁₀ amorphous alloy in the as-quenched state and after irradiation with N⁺ ions are investigated. CEMS spectra show that the irradiated surface at the air side of the ribbons was significantly affected. On the other hand, no noticeable changes were observed at the opposite wheel side. More deep subsurface regions are also not altered as evidenced by CXMS spectra. Thermomagnetic measurements have shown presence of two magnetically different phases with well distinguished Curie points. They can be ascribed to the amorphous matrix and crystalline phases. The latter were quenched-in during the production process and/or induced by ion bombardment. Curie temperatures of the amorphous matrixes were calculated using the Heisenberg model. For the as-quenched and irradiated ribbons they are of 223 K and 228 K, respectively. The behaviour of coercivity versus temperature was also analysed.