Substrate effects on thermal instability development in high T-c superconducting thin films with transport current

摘要

The thermal instability development in a high T-c superconducting thin film carrying a transport current is studied both experimentally and theoretically. The normal phase propagation velocity nu is measured by means of both direct current and pulse current methods in a wide range of the transport currents I. It is shown that to explain the measured dependence nu(I) a non-linear heating over the thickness of a substrate, of which the reverse side is stabilized at a temperature T-o should be taken into account. The corresponding theory based on the solution of the non-stationary two-dimensional heat balance equation is developed and compared with experimental data. The results obtained may be of importance in the study of superconducting switching devices. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 15]