Magnetic anisotropy of Ho-Fe-Co-Cr intermetallic compounds

Starting with a Ho3(Fe1−xCox)29−yCry, (x,y) = (0.6,4.5) and (0.8,5.5) nominal stoichiometry, a disordered variant of the hexagonal 2:17 phase (Th2Ni17-type, S.G. P63/mmc) occurs, since both the monoclinic 3:29 and the transition-metal-rich disordered Th2Ni17-type hexagonal compounds have the same rare earth to transition metal ratio, 1:9.7. The magnetic properties and the magnetocrystalline anisotropy of these compounds have been investigated. The anisotropy constant, K's, and the anisotropy field, μ0HA, values have been deduced from the magnetization curves measured on powder samples magnetically aligned in a rotating magnetic field. The compound with (x,y) = (0.8,5.5) shows a compensation point at about 55 K. The magnetic anisotropy of both compounds is that of easy-plane from room temperature to low temperatures down to 5 K.