Transport properties and point contact spectra of Ni_xNb_{1-x} metallic glasses

Abstract

Bulk resistivity and point contact spectra of Ni_xNb_{1-x} metallic glasses have been investigated as functions of temperature (0.3-300K) and magnetic field (0-12T). Metallic glasses in this family undergo a superconducting phase transition determined by the Nb concentration. When superconductivity was suppressed by a strong magnetic field, both the bulk sample R(T) and the point contact differential resistance curves of Ni_xNb_{1-x} showed logarithmic behavior at low energies, which is explained by a strong electron - "two level system" coupling. We studied the temperature, magnetic field and contact resistance dependence of Ni_{44}Nb_{56} point-contact spectra in the superconducting state and found telegraph-like fluctuations superimposed on superconducting characteristics. These R(V) characteristics are extremely sensitive detectors for slow relaxing "two level system" motion.

arXiv comment4 pages, 5 figures

References in corpus (1)

• The 2-Channel Kondo Model II: CFT Calculation of Non-Equilibrium Conductance through a Nanoconstriction containing 2-Channel Kondo Impurities

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