Neutron scattering techniques have been used to study the structureof amorphous materials. The experiment used both polarizedincident and scattered neutron beams andso did not need to assume a collinear magnetic structure. Five different Fe-based amorphous materials were studied and the structures were found to differ. In the case of Fe8,B,, the spins are canted in a magnetic fieldof 2 T about 30" from the applied direction. The transverse components have only very short-range order. Other materials show less canting. Fe-Ni amorphous materials shows a large amount of disorder in the spin directions and in the aligned moment. ThissuggeststhattheNi atomsdocarryamagneticmomenlbulthatit may be largely misaligned to the Fe moment. Inelastic measurements of the density of magnetic statesshow averydifferent distribution tothatexpected fromapowderedferroma$net.This may arise from 'hidden' short-wavelength excitations.

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The atomic-scale magnetic structures of two terbium-substituted (Fe0.83−xTbx)B0.17 metallic glasses have been determined by polarized beam neutron scattering measurements using the IN20 spectrometer at the Institut Laue-Langevin, Grenoble. The four spin-dependent, neutron scattering cross-sections were measured in absolute units for the two glasses. The spin-flip cross-sections and were found to be small; they were independent of the scattering vector Q, independent of the temperature and were also of the same magnitude as the nuclear incoherent cross-section, within experimental errors. These observations indicate that the magnetic structure in these glasses must be collinear. The non-spin-flip cross-sections were found to have a hitherto unobserved shift of the first peak between the and channels. A (collinear) ferrimagnetic state which is consistent with the spin-flip cross-sections is therefore proposed for these glasses. The magnetic moments on the terbium atoms are aligned antiparallel to those on the iron atoms, and the values of both moments reduce to zero by x = 0.50 terbium, in agreement with magnetization data. A calculation of the non-spin-flip cross-sections based on this model correctly predicts the shift of the first peaks. This behaviour arises because of the ferrimagnetic correlations between the magnetic moments and the very strong magnetic scattering from the terbium atoms.

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Neutron scattering with polarization analysis has been used to examine the spindependent absolute neutron cross-section of Fe 80 B 20 , Fe 70 Ru 10 B 20 and Fe 62 Ru 18 B 20 metallic glasses. Fe 80 B 20 is shown to be a canted ferromagnet with an average canting angle of approximately 49 • in a field of 2 T. Contrary to expectations, there is little or no canting in the samples containing ruthenium as proved by the absence of spin-flip scattering. The magnetic structure of Fe 62 Ru 18 B 20 has been studied as a function of temperature and magnetic field history. When cooled to 4.2 K in zero field the observed scattering is not consistent with the presence of a spin-glass phase. An increase in the projection of the moments in the direction of the applied field was observed when the sample was cooled to 4.2 K in an applied field of 2 T. The results are discussed in the context of current structural models of (Fe 80−x Ru x )B 20 glasses.