NONLINEAR SELF-OSCILLATIONS IN NORMAL SUPERCONDUCTING CONTACTS

The non-linear properties of mechanical normal-superconducting contacts are investigated. It is shown that the near-boundary superconductor conductivity jump due to direct current through the heterosystem would induce not only the known N-shaped non-linearity in I-V characteristics (Ta-(SnPb) heterosystems) but also the S-shaped non-linearity in I-V characteristics (In-Bi heterosystem). This conclusion follows from the conditions required to observe self-oscillations. The nature of the non-linearity in the In-Bi heterosystem which is non-traditional for conductors is analysed using self-oscillation parameters.