Nature of anomalous electrical resistance in Co73-xFe4CrxSi12B11 amorphous microwires

Abstract

Influence of structural relaxation and composition of microwires of metallic amorphous alloys Co73-xFe4CrxSi12B11 (x = 0, 2, 4, 6, 8) on the character and mechanisms of temperature dependence of electrical resistance r(T) has been studied in a wide temperature range (from 4.2 K to crystallization temperature). It is shown that alloys with more than 2 at.% Cr have a number of specific properties, which are significantly differentiate them from Fe- and Ni-rich alloys, as well as many Co-rich amorphous alloys. The features of Cr-doped Co-rich alloys are explained by two reasons: firstly, very strong quantum interference effects of the electron-electron interaction and weak localization of electrons caused by scattering of electrons by the potential created by randomly distributed chromium atoms, and secondly, partially reversible compositional structural relaxation leading to clustering of the amorphous phase at T > 300 °C. It is assumed that the resulting Cr-rich clusters, in which chromium atoms are bonded to metalloid atoms, can enhance these interference effects. The contributions from various mechanisms of interaction and scattering of electrons to the change in electrical resistance with temperature and composition of the alloy are analyzed. The fitting parameters for them are determined and compared with the known data.