Small-Angle Neutron Scattering Measurements of the Averaged Internal Structures in Neodymium-Iron-Boron (Nd-Fe-B) Sintered Magnets

Small-angle neutron scattering (SANS) method is applied for the investigation of average internal structures of Neodymium-Iron-Boron (Nd-Fe-B) sintered magnets. The information obtained using SANS is average structure of the magnet and sometimes complementary to the microstructural information using the scanning electron microscopy. The SANS patterns were sensitive to internal structural changes introduced by the sintering process and the formation of magnetic domains, and we found a correlation between the SANS intensity and the coercivity. These observations indicate that SANS is a promising tool to investigate the origin of the coercivity of Nd-Fe-B sintered magnets. This article is a brief introduction to SANS and gives several examples of its application to investigation of Nd-Fe-B sintered magnets in the viewpoint of the correlation between the average structure and the coercivity.