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

A. Halbritter·O. Yu. Kolesnychenko·G. Mihaly·O. I. Shklyarevskii·H. van Kempen
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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.

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A. Halbritter, O. Yu. Kolesnychenko, G. Mihaly, O. I. Shklyarevskii, H. van Kempen. 2000-02-01. Transport properties and point contact spectra of Ni_xNb_{1-x} metallic glasses. https://doi.org/10.1103/physrevb.61.5846

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