Magnetic properties of Ho₂(Co_1-xFe_x)₁₇compounds

Abstract

The structure and magnetic properties of Ho2(Co1-xFex)17 compounds with x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8 or 1.0 have been investigated by x-ray diffraction (XRD) and magnetization measurements. XRD patterns demonstrate that all samples are single phase with the hexagonal Th2Ni17-type structure. The substitution of Fe for Co initially leads to a increase in the lattice constant a and unit cell volumes v and then a small decrease. The Curie temperatures decrease monotonously with increasing Fe concentration. Saturation magnetization increases with x and then decreases, attaining a maximum at x = 0.2. The magnetic anisotropy phase diagram of Ho2(Co1-xFex)17 compounds has been determined from the temperature dependence of magnetization and the XRD patterns of magnetically oriented powder samples. The spin-reorientation temperature of Ho2(Co1-xFex)17 compounds is found to decrease with increasing Fe content for x<0.3 and then increase for x>0.3, attaining a lowest value of 248 K at x = 0.3.