Paramagnetic Impurities and Thermal Stability in Type II Superconductors

Abstract
Magnetization, critical current, and flux‐jump measurements have been made on superconducting La3In containing 1 at. % Gd. The previously reported nonmonotonic dependence of upper critical field on temperature has been confirmed. A low‐temperature high‐field regime is observed where critical currents increase with increasing temperature. This leads to improved thermal stability, i.e., less flux jumping, at low temperatures. The Gd magnetization data are near free‐ion values, indicating only slight interaction effects.