Magnetic Domain Evolution in Sintered Nd–Fe–B Magnet during Magnetization Process

In the present study, the magnetic domains and their evolution during magnetization process have been investigated for sintered Nd–Fe–B permanent magnets with Kerr microscopy. Observation of the magnetic domain evolution process during magnetization process shows that some domain walls were pinned at the grain boundary area under magnetic field up to 5 kOe. It is suggested that magnetic interaction between individual Nd2Fe14B grains contacting to each other leads to appearance of small closed domains near the grain boundary area, which are responsible for the pinning effect.