Magnetic microstructures of neodymium in Nd2Fe14B permanent magnet by hard x-ray magnetic-circular dichroism using focused x-ray beam

Magnetic microstructures of neodymium (Nd) in a Nd–Fe–B magnet were investigated by the hard x-ray magnetic circular dichroism (HXMCD) with a focused synchrotron circular-polarized beam (<2 μm). Magnetic domain and Nd concentration were simultaneously acquired by measuring Nd HXMCD and Nd Lα intensity. The magnetic momentum of Nd was high for Nd2Fe14B microdomains but was nearly zero at Nd-rich precipitates. This clearly indicates the magnetic momentum distributions are well correlated with the local concentration of Nd. Our experiments demonstrate the feasibility of studying magnetic microstructures by HXMCD mapping, which thus enables a discussion of the bulk magnetic behavior of Nd–Fe–B magnets.