Magnetism of Nd–Fe films as a model of grain boundary phase in Nd–Fe–B permanent magnets

Abstract To clarify the magnetism of an amorphous grain boundary (GB) phase in Nd–Fe–B sintered magnets, the magnetic properties of Nd 100− x Fe x films with various compositions have been investigated both experimentally and theoretically. The model films exhibit ferromagnetism at room temperature when the Nd content is lower than 70 at. %. First-principles calculations indicate ferromagnetism in fcc Nd–Fe alloys for x < 70, which supports recent experimental works on the intergrain exchange coupling of Nd–Fe–B sintered magnets.