Strain maps for Nd2Fe14B grains in Nd-Fe-B sintered magnets, representing elongation/contraction in the spacing of c planes, have been revealed by analyzing artificial moiré fringes in scanning transmission electron microscopy images. The strain maps were collected from several types of Nd2Fe14B grains in contact with metallic-Nd (m-Nd), Nd2O3, NdOx, and thin grain boundary phases. A maximum value of strain of ∼1.2% was observed at a Nd2Fe14B/m-Nd interface. The magnitude of strain for the interfaces with Nd2O3 and NdOx phases was 0.4-0.5%. The strain was negligible in the vicinity of the grain boundary phase. It appears that the observations are smaller than the theoretical values of strain that may cause a significant change in the magnetocrystalline anisotropy of the Nd2Fe14B phase.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys