BURNING OF HIGH T-C BRIDGES

Burning of superconducting thin film bridges by large transport curren ts (up to densities of 2 x 10(7) A/cm(2)) is investigated by magneto-o ptical imaging of flux distribution and low-temperature scanning elect ron microscopy providing T-c maps. It is shown that the destruction is preceded by significant penetration of magnetic field inside a weak-p inning region. In bridges containing extended defects magneto-optic in vestigation is sufficient to locate the incipient burning region. In h igh-quality bridges free from such defects only a combination of the t wo techniques will allow prediction of the place of fatal destruction. (C) 1997 American Institute of Physics.