Recent development of basic magnetism in interstitially modified rare-earth iron nitrides R 2Fe 17N 3

Abstract

EPMA-line profiles for N-element in Sm 2Fe 17N x indicate that under low N 2-gas pressure, nitrogen absorption into grain interior is mainly due to diffusion of nitrogen atoms, while under high N 2-gas pressure, the grain growth of fully nitrogenated phase Sm 2Fe 17N 3 becomes more dominant than diffusion, making high-pressure nitrogenation effective for fabricating a high-quality nitride. Neutron diffraction studies of Y 2Fe 17 and Y 2Fe 17N 3.1 prepared by high N 2-gas pressure revealed that the N-atoms fully occupy at the 9e-sites (99.5%) and a small amount of N-atoms locates on the 18g-sites (4%). The introduction of N-atoms into Y 2Fe 17 led to such a strong modification in the Fe magnetic moment that the moment of the 18f-Fe atoms being the nearest to the 9e-N atoms is the smallest (∼2.0 μ B), whereas the 6c-Fe atoms being the farthest from the 9e-N atoms have the largest moment of ∼2.9 μ B at 10 K. The magnetization measurements of Nd 2Fe 17N 3 single crystal clarified a strong enhancement of crystalline electric field (CEF) acting on R-atoms upon nitrogenation, leading to almost three times larger CEF-parameter A 2 0 in nitride than in host compound.