Nd L3-edge x-ray absorption near-edge structure spectroscopy of nanocrystal-dispersed soft-magnetic alloys containing very small amounts of Nd

Abstract

The Nd L3-edge XANES spectra of Nd-added FINEMET type soft magnetic alloys were characterized. Meltspun amorphous metallic alloys with compositions of Fe73.5Si13.5B9Cu0.5Nb3Nd0.5 and Fe73.5Si13.5B9Nb3Nd1 were heat-treated at 850 K for various durations up to 1 h in order to induce crystallization of nanocrystalline phases inside the alloys. The introduction of small amounts of Nd to the FINEMET-type alloys resulted in enhanced crystallization temperatures. The structural evolution of Nd over time was inferred based on changes of the Nd L3-edge x-ray absorption near-edge structure spectra. When coexisting with Cu atoms, Nd atoms clustered at the early stage of heat treatment and generally remained unaltered over time. In the absence of Cu atoms, however, the neighboring atoms of Nd changed over time. Magnetic properties of the heat-treated samples were discussed in connection with such local structural changes occurring at Nd sites in addition to the typical role of Cu atoms in crystallization behaviors.