Sperimagnetism in Fe(78)Er(5)B(17) and Fe(64)Er(19)B(17) metallic glasses: I. Moment values and non-collinear components

Magnetization measurements have been made on a Fe(64)Er(19)B(17) glass, which exhibits ferrimagnetic compensation at T(comp) = 112 K, and polarized beam neutron scattering measurements have been made on Fe(78)Er(5)B(17) and Fe(64)Er(19)B(17) glasses to supplement the measurements made earlier on Fe(64)Er(19)B(17). The magnetization data were analysed with a phenomenological model, to find the magnetic moments and their components needed to interpret the neutron data. Four spin-dependent scattering cross-sections were obtained in absolute units from each neutron experiment, to determine the atomic-scale magnetic structures of the two glasses. The finite spin-flip cross-sections confirmed that these (Fe, Er)(83)B(17) glasses are non-collinear ferrimagnets. The cross-sections were calculated using a model based on random cone arrangements of the magnetic moments. The moment values and the random cone angles were refined in the calculations, which produced good agreement between the calculated curves and the experimental data. The forward limit of the spin-flip cross-sections vertical bar partial derivative sigma (+/--/+)/partial derivative Omega vertical bar(Q=0) of the Fe(64)Er(19)B(17) glass which peaked at T(comp) and the temperature variation of the total scattering amplitudes. (b -/+ p(parallel to) (Q)) suggested that the random cone angles open fully so that the collinear components p(parallel to) (Q) tend to zero at T(comp). The ferrimagnetic compensation is therefore characterized by an equality of the magnetic sublattices; the reversal of the magnetic structure and a compensated sperimagnetic phase which appears at T(comp).