First-principles study on magnetism of a crystalline grain-boundary phase in Nd–Fe–B permanent magnets

We report the magnetism of fluorite Nd−Fe alloys containing 60 ~ 70 at% of Nd as a possible crystalline grain- boundary phase for Nd−Fe−B permanent magnets. Due to strong magnetic interactions between Nd and Fe, binary fluorite Nd−Fe alloys exhibit high Curie temperatures. The Curie temperature decreases significantly with the addition of Ga or Cu suggesting that these elements are indispensable for the demagnetization of the grain- boundary phase.