Anomalous electrical conductivity in rapidly crystallized Cu100-xZrx (x = 50-66.6) alloys

Abstract

Cu100-xZrx (x = 50, 54, 60 and 66.6) polycrystalline alloys were prepared by arc-melting. The crystal structure of the ingots has been examined by X-ray diffraction. Non-equilibrium martensitic phases with monoclinic structure were detected in all the alloys except Cu33.4Zr66.6. Temperature dependencies of electrical resistivity in the temperature range of T = 4-300 K have been experimentally obtained as well as room temperature values of Hall coefficients and thermal conductivity. Electrical resistivity demonstrates anomalous behavior. At the temperatures lower than 20 K, their temperature dependencies are non-monotonous with pronounced minima. At elevated temperatures they have sufficiently non-linear character which cannot be described within framework of the standard Bloch-Grüneisen model. We show that experimental resistivity dependencies may be perfectly fitted by generalized Bloch-Grüneisen model with variable Debye temperature. We found that both the electrical resistivity and the Hall coefficients reveal metallic-type conductivity in the Cu-Zr alloys. The estimated values of both the charge carrier mobility and the phonon contribution to thermal and electric conductivity indicate the strong lattice defects and structure disorder. © 2015 Elsevier B.V.