Powder neutron diffraction study for magnetism of rare-earth in (Nd,Ce,La)_2Fe_(14)B

摘要

To reduce expensive Neodymium in rare-earth magnets Nd_2Fe_(14)B without decrease of magnetic properties, cheap Cerium is paid attention. In general, the Ce atom is in non-magnetic Ce~(4+) state. However, when the magnetic Ce~(3+) state is stable, the Ce should work as a substitution for Nd. Previous research reported that the larger ionic radii rare-earth prefer the larger cell volume. The magnetic Ce~(3+) state has larger atomic radii (1.15 A) than that of Ce~(4+) state (1.01 A). Therefore, the La (1.17 A) is doped as a spacer to stabilize the Ce~(3+) state. Previous powder neutron diffraction study reported that Ce atom in (La,Ce)_2Fe_(14)B has no moment. Following the previous results, in this study, powder neutron diffraction experiments were performed on (Nd,Ce,La)_2Fe_(14)B to evaluate the rare-earth moment and the Ce state.