Amorphous Fe-B solids have been made over a wide range of compositions, up to 90 at.% Fe. Magnetic ordering occurs at a percolation-like threshold of $x_c\simeq 38$. Above $x_c$, the ordering temperature ($T_c$) rises sharply and linearly with Fe content. The value of $T_c$ reaches a maximum at about $x=70\mathrm{}$ and decreases at the Fe-rich side. There is no accompanying maximum in the average Fe moment, which increases monotonically with Fe concentration.

• Received 17 February 1981

DOI:https://doi.org/10.1103/PhysRevB.24.1556