Crystallographic and magnetic studies on iron-rich mixed rare-earth intermetallics (Nd/Tb)2(Fe/Al)17

Abstract: The crystal structure and magnetic properties of Nd2−x Tb x Fe17 and NdTbFe17−y Al y compounds were studied by means of X-ray diffraction and magnetization measurements. All the samples show the rhombohedral Th2Zn17-type structure with space group . For Nd2−x Tb x Fe17 compounds, the lattice parameters decrease with increasing Tb concentration, and the Curie temperature increases with the Tb content while the saturation magnetization decreases linearly at a rate of 10.54μ B/f.u. per Tb atom. For NdTbFe17−y Al y compounds, the substitution of Al for Fe leads to an increase in lattice parameters a, c and unit-cell volume V. The Al atoms preferentially occupy 18h site at low Al concentration whereas prefer to occupy 6c and 18f sites at high Al concentration. The Curie temperature increases with Al content up to y =3 then decreases for 3≤ y ≤8. X-ray diffraction of magnetically pre-aligned samples indicates that the easy magnetization direction of the samples changes from planar to c-axial with increasing aluminum concentration. The saturation magnetization of compounds decreases with increasing Al concentration. [Copyright &y& Elsevier]