The magnetic behavior of nanoglass Fe79B21 powder has been investigated by Mossbauer spectroscopy in a temperature range from 5 to 295 K together with one amorphous Fe80B20 ribbon prepared by melt-spinning. It is found that average hyperfine fields for the powder sample are smaller than those for the ribbon sample in the whole temperature range studied. The reduced average hyperfine field of nanoglass Fe79B21 powders follows the Bloch's law, H(T)/H(0)=1-BT3/2. The B paramaters for the powder and the ribbon samples are found to be about 2.8 x 10-5K3/2 and 2.2 x 10-5K3/2, respectively, indicating that the degree of local structural disorder in the powder sample is higher than that in the ribbon.
Nanostructured Materials, 1999, Vol 12, Issue 5-8, p. 843-846