The effects of iron substitution on the magnetization, the magnetic anisotropy, the spinreorientation
temperature, and the Curie temperature of Y(Co1-xFex)4B have been studied on the cobaltrich
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-reorientation 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 fieldoriented
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.
