Temperature Dependence of Critical Current Density in Superconducting Tin Thin Films

Measurements of critical current density in thin tin films have-been made utilizing an induction method. The results confirm previous critical current measurements near T and further reveal a peak in the critical current density near a reduced temperature (T/T/sub c/) of 0.65. This behavior deviates markedly from theoretical predictions except near T/sub c/. At the lowest temperatures the magnitude of the critical current is considerably lower than the asymptotic value expected at T = 0. These resuits indicate that some process not presently accounted for by theory is the limiting factor in the critical current density in soft superconducting films. (H.D.R.)