I. Microwave Impedance of Superconducting Weak Links. I. Effects of Nonequilibrium Quasi-Particle Distributions in Superconducting Weak Links.
Abstract
Nonequilibrium properties of proximity coupled superconducting weak links are studied. The impedance of a current-biased weak link was calculated analytically on the basis of several different theoretical models for the supercurrent and the quasi-particle current, and the results were compared with experimental measurements. A very small tunnel junction was used to inject quasi-particles directly into the center of a proximity effect weak link. It was found that the critical current of the weak link was, over a wide range of experimental conditions, proportional to (-alpha square root of P), where P is the injection power and alpha is a constant. The final experiment consisted of using a small tunnel junction as a probe of the nonequilibrium quasi-particle chemical potential inside a proximity effect weak link. The nonequilibrium value of potential was produced by simultaneously passing a dc bias current and a microwave current through the weak link. For most values of microwave current measured value of the quasi-particle chemical potential was proportional to the dc supercurrent carried by the weak link.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- May 1977
- Bibcode:
- 1977PhDT.........9F
- Keywords:
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- Physics: Condensed Matter;
- Electrical Impedance;
- Linkages;
- Microwave Coupling;
- Superconductors;
- Current Distribution;
- Electric Current;
- Electric Potential;
- Electron Tunneling;
- Mathematical Models;
- Solid-State Physics