Spontaneous Hall effect and resistivity of Fe-Co-Ni-base glasses

The spontaneous Hall effect and dc resistivity have been measured at room temperature in the glassy alloy series Fe_80-xCoₓB₂₀ (0≤x≤80 at.%) and Fe_80-xNiₓB₂₀ (0≤x≤60 at.%) and in Co₄₀{Ni}₄₀B₂₀ glass. The density-derived thicknesses used herein give smaller values of Rₛ and ρ than generally reported for metallic glasses. Because of the relatively large resistivities of metallic glasses, ρ10^-4 ▪ cm, the nonclassical side-jump mechanism is expected to dominate the spontaneous Hall effect. The magnitude of the side jump in Fe₈₀{B}₂₀$ glass is comparable to that in crystalline Fe and Fe-base dilute alloys, viz. ${10}^{{-}8}$ cm. The spontaneous Hall conductivity ${{γ}}Hs$ shows a proportionality to the magnetostriction ${{λ}}ₛ$ as predicted theoretically with a slope that is close to that observed in crystalline Fe-Ni alloys. The compositional dependence of ${{γ}}Hs$ is interpreted in terms of a split-band model in which charge is transferred from boron to the transition-metal $d$ states in the glassy alloys. The applicability of the split-band model to these data implies that an intrinsic spin-orbit interaction involving the itinerant $d$ electrons is effective here and not a spin-other-orbit interaction.