Investigation of structure and electrical transport in partially nanocrystallized amorphous soft magnetic alloys

Abstract

X-ray diffraction patterns of melt-spun Fe-Cu-Nb-Si-B (FINEMET-type) alloys reveal that crystallites of Fe₂Si and Fe₃B phases with average sizes of 15(5) and 20(2) nm are present in the surface layer of thickness ≈10 Å and these nanocrystallites occupy 5-10% of the total volume. The results of an elaborate analysis of the high-resolution electrical resistivity data taken in a temperature range from 13 K to 300 K and their discussion in the light of existing theories demonstrates that the enhanced electron-electron interaction (EEI), quantum interference (QI) effects, inelastic electron-phonon scattering, coherent electron-magnon (and/or electron-spin fluctuation) scattering are the main mechanisms that govern the temperature dependence of resistivity. Of all the inelastic scattering processes, inelastic electron-phonon scattering is the most effective mechanism to destroy phase coherence of electron wavefunctions. The physical quantities such as diffusion constant, density of states at the Fermi level and the phase-breaking time, determined for the first time for the alloys in question, exhibit a systematic variation with the copper concentration.