A high-resolution neutron study of Y2Fe17-xGax (x = 5,7)

The crystallographic and magnetic structures of (x= 5, 7) compounds at room temperature have been refined by Rietveld analysis of the high-resolution neutron powder diffraction data. The analysis indicates that (x= 5, 7) compounds have-type structures (R3m). The Ga atoms only occupy preferentially 18h and 18f sites in compounds, but Ga atoms occupy preferentially 18h, 18f and 6c sites in compounds. The magnetic moments of all of the Fe atoms of compounds display ferromagnetic alignment, lie in the plane perpendicular to the sixfold axis and exhibit planar magnetic anisotropy. In contrast, the magnetic moments of all of the Fe atoms of compounds lie parallel to the sixfold axis and exhibit easy-axis magnetic anisotropy.