Magnetization curves were measured on Ni3Fe and Fe75Al12.5Ge12.5, nanocryst
als of different grain sizes. These materials were prepared by high-energy
ball milling, followed by annealing at various temperatures. The alloy comp
ositions were chosen because they have low magnetostriction in bulk form, i
mplying that strain in the samples should have little effect on their magne
tic properties. The M-H magnetization curves were used to obtain the coerci
vity, the maximum permeability, and the saturation magnetization. Differenc
es in these magnetic properties were related to changes in grain size and i
nternal RMS strain. In spite of the low hulk magnetostriction of these mate
rials, the internal stress controlled the coercivity. The changes in permea
bility, however, were not as expected from the trend in grain size. We sugg
est that the powder morphology, plays an important role in determining the
soft magnetic properties of these nanocrystalline alloys. (C) 2000 Acta Met
allurgica Inc.