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Properties of superconducting weak links

Thesis/Dissertation ·
OSTI ID:6199263

Josephson junctions (tunnel junctions, point-contacts and microbridges) are useful in a wide variety of applications such as the precision measurement of voltage and magnetic field. In recent years there has been increased interest in the high frequency (10 GHz-1000 GHz) application of these devices. Most of these applications have been theoretically discussed in terms of a simple model of the junction known as the resistively-shunted junction model. Predictions of this model are reviewed along with a discussion of phenomena predicted by the microscopic tunnelling theory and relaxation models based on time-dependent Ginzburg-Landau theory. Particular attention is focused on the phase-dependent conductivity: the so called cos phi conductance. The discrepancy between theory and experiment in this regard is discussed and suggestions are made about how this discrepancy may be resolved. Microwave reflection measurements on a point-contact in a microwave resonator are described. The data are consistent with the relatively-shunted junction model including a phase-dependent conductance with a negative sign. The dc I-V characteristics have also been measured at finite voltage and certain features of these characteristics are discussed.

Research Organization:
Stanford Univ., CA (USA)
OSTI ID:
6199263
Country of Publication:
United States
Language:
English