First-Principles Study of Formation and Properties of Fcc-NdOx in Nd-Fe-B Sintered Magnets
The NdOx phase formed at the Nd/Nd-Fe-B interface in Nd-sputtered Nd-Fe-B sintered magnets is paid rather attention recently due to its important role in coercivity generation of surface Nd-Fe-B grains. Its crystal structures have been reported to vary with the change of the oxygen concentration, and the disorder fcc phase derived from Nd2O3-C-type structure to be the main form of existence. To understand the formation mechanism of this fcc-NdOx interfacial phase, the stability of all oxygen concentration range of Nd-O system has been investigated from the first principles. Based on LSDA+U calculations for selected ordered phases at various oxygen concentration in Nd-O, the Cluster Expansion Method (CEM) is applied to evaluate the formation energy, density of states and other properties of disorder phase.
Jian-Feng Nie and Allan Morton
Y. Chen et al., "First-Principles Study of Formation and Properties of Fcc-NdOx in Nd-Fe-B Sintered Magnets", Materials Science Forum, Vols. 654-656, pp. 1674-1677, 2010