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In order to settle the question of homogeneous versus inhomogeneous ordering in amorphous Fe-Zr alloys, we have obtained Mossbauer spectra with well-defined magnetic texture and without line overlap by subtracting spectra measured with and without a small polarizing field. These spectra allow us to show that P(Bhf) has no bimodal structure at any temperature, and there is no paramagnetic component in the spectra above TX,,. We therefore rule out the possibility that magnetically isolated clusters or precipitates play a role in the ordering. We also present high-field spectra which show homogeneous transverse-spinfreezing at-28 K in a-FegOZrl,.

The magnetic ordering behavior of Fe91Sc9 has been studied by Mössbauer spectroscopy and magnetization measurements. Mössbauer spectra in an external field parallel to the γ beam clearly shows that the noncollinearity develops as soon as magnetic order appears, indicating a single transition to an asperomagnetic state, in contrast to the mean-field theory and Monte Carlo simulations which predict a transition from paramagnet to spin glass for strongly frustrated alloys. A possible origin for this discrepancy is discussed.

A cluster relaxation model has been used to fit the Mossbatter spectra of iron-rich amorphous Fe-25 alloys near their ordering temperatures. While the results are consistent with the presence of relaxation, deduced cluster sizes are an order of magnitude smaller than expected. Incorporating static magnetic and structural disorder into the model extends the temperature range over which the data may be fitted.