Self-consistent spin-polarized calculations of the electronic and magn
etic structure of amorphous FexB1-x alloys, based on realistic models
of the glass-structure generated by a simulated molecular-dynamics que
nch using tight-binding-bond forces between the atoms, are presented.
The calculations predict average Fe moments in good agreement with exp
eriment and small negative magnetic moments on the B sites whose origi
ns are in a covalent coupling of the B p-states to the Fe spin-down ba
nd. In the glass richest in Fe, a few Fe sites acquire a negative mome
nt. It is found that the formation of negative Fe moments is due to a
local-environment effect.