EFFECTS OF IRON SUBSTITUTION ON THE MAGNETIC-ANISOTROPY OF YCO4B

The effects of iron substitution on the magnetization, the magnetic anisotropy, the spin-reorientation temperature, and the Curie temperature of Y(Co(1-x)Fe(x))4B have been studied on the cobalt-rich side for x values below 0.4. Temperature-induced spin-reorientation phenomena may be observed in compounds with x values below 0.02 by inspecting the low-field magnetization curves of bulk polycrystalline samples and by observing the change in the easy direction in field-oriented powdered samples. The spin-orientation temperature shifts from 145 K for YCo4B to higher values with increasing x and the phenomenon disappears for values larger than 0.03. By analyzing the magnetization curves of field-oriented powder samples, the magnetic anisotropy has been evaluated. The value for the first anisotropy constant K1 at 4.2 K decreases in a nonlinear way with increasing x values and reaches a minimum around x = 0.3.