Electrical and thermal behavior of patterned superconducting disks

Apparatus for the investigation of low and high-T/sub c/ superconducting spirals has been designed and built. The device is capable of measuring the characteristic of superconducting spirals. The superconducting spirals are on a normally conducting substrate. The normally conducting substrate serves as a shunt between the superconducting turns, serving as a distributed quench protection resistor. Samples with both high and low electrical resistance substrates have been tested on this apparatus. Preliminary results of the tests of both high-T/sub c/ (Bi-Sr-Ca-Cu-O) and low-T/sub c/ (Nb-Ti) thick-film spirals have been investigated. Current distribution in films during quench has been studied experimentally. Generation of normal zone and hysteresis current-voltage characteristics have been discovered in high-T/sub c/ superconducting spirals on silver plate. It is shown that frequency of generation of normal zone depends at under certain conditions (transient current, magnetic field, temperature and resistivity of substrate). The results are being analyzed with models.<>