Electrical resistivity of amorphous Fe_90-xCo_xZr₁₀ alloys: weak localization and spin fluctuation effects

Abstract

The results of electrical resistivity (ρ) measurements performed on amorphous Fe_90-xCo_xZr₁₀ alloys in the temperature range 77 K to 350 K are presented and discussed in the light of existing theoretical models. Besides unambiguously identifying weak localization, electron-phonon scattering, electron-magnon scattering and scattering of conduction electrons from spin fluctuations as main mechanisms governing the temperature dependence of ρ within the temperature range covered in this work, the present results demonstrate that inelastic scattering of electrons from longitudinal phonons provides the most effective dephasing mechanism. Weak localization effects basically account for the negative temperature coefficient of ρ observed for temperatures below the minimum and the inelastic scattering time or dephasing time increases rapidly with Co concentration. Spin fluctuation effects show up clearly for temperatures in the vicinity of the Curie temperature through a contribution to ρ(T) which varies with temperature as T^5/3. That spin fluctuations get suppressed by Co substitution is strongly indicated by a continuous decline of the coefficient of the T^5/3 term with increasing Co concentration.