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

Starting with a Ho₃(Fe_1−xCo_x)_29−yCr_y, (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, μ₀H_A, 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.