Hu Boping

Formation and magnetic properties of a novel Gd3(Fe,Ti)29Ny nitride

The novel Gd3(Fe0.978Ti0.022)29 compounds and their nitride have been synthesized. The x-ray diffraction patterns of the Gd3(Fe,Ti)29Ny and its parent compounds were indexed in the Nd3(Fe,Ti)29-type structure with a monoclinic symmetry and space group P21/c. Both the nitride and the parent compounds exhibit ferrimagnetic coupling. Nitrogenation led to an increase in Curie temperature and saturation magnetization. The Curie temperatures are 517 K for the parent and 765 K for the nitride. The saturation magnetizations σs at 4.2 K are 101.9 A·m2/kg for the parent and 128 A·m2/kg for the nitride. Both the nitride and parent exhibit a planar anisotropy. Nitrogenation led to a decrease of the contribution of Fe-sublattice to planar anisotropy. The anisotropy fields at 4.2 K are 9.8 T for the parent and 6.5 T fot the nitride.

NEUTRON-POWDER-DIFFRACTION STUDY OF ErFe 11.35 Nb 0.65 AND ErFe 11.35 Nb 0.65 N y

ErFe11.35Nb0.65 and ErFe11.35Nb0.65Ny have been synthesized and neutron-powder-diffraction experiments at room temperature performed. The ErFe11.35Nb0.65Ny nitride, obtained by gas-solid reaction, retains the ThMn12-type structure of its parent compound. The Nb atoms occupy 8i sites and the nitrogen atoms are located at 2b sites. The atomic magnetic moments of the Er ions are antiparallel to those of the Fe atoms. Upon nitrogenation, the lattice cell expands mainly along the a-axis and the atomic magnetic moments of Fe are enhanced.

A neutron powder diffraction study of the structure in Nd2Fe17Nx(x = 2.5, 3.0, 5.5)

The crystallographic and magnetic structures of Nd2Fe17Nx (x=2.5, 3.0, 5.5) at room temperature were refined by Rietveld analysis of neutron powder diffraction data. We found that Nd2Fe17Nx has a Th2Zn17 type structure (S. G. Rm) and the nitrogen atoms occupy both 9e and 18g sites simultaneously and at different rates.