Various Characteristics of Pb-In-Sn Alloy Superconductor of ∂Jc/∂T>0

Measurements on magnetic properties in a bulk Pb-In-Sn alloy superconductor were carried out. H-I characteristics in the superconducting wire were also measured. In a certain range of temperature and magnetic field, magnetizations of the bulk sample or critical current densities of the wire one increased with increasing temperature, i.e., the superconductor exhibited the property ∂Jc/∂T>0.In the regoins where ∂Jc/∂T is positive or negative, flux jumping characteristics, the effects of magnetic field sweep on magnetizations, current-voltage behaviours and so on were measured. In the positive region, intrinsically stable behaviour was confirmed; no flux jumps were observed, magnetizations increased by a certain value with field sweep rates and the voltage was reversible up to fairly large current over its critical current. While in the negative region. flux jumps occurred.