Anomalous magnetization behaviour in fine filamentary NbTi superconducting wires

Magnetization curves of various fine filamentary superconducting wires with Cu as well as a CuNi matrix have been measured. Anomalies in the shape of these curves in a low external magnetic field were observed. A strong influence of both filament diameter and matrix type on the field above which the initial magnetization curve deviates from the straight line was detected. A considerable influence of the current flowing through the sample on the magnetization was observed as well. A model based on the proximity effect is proposed for the explanation of the magnetization anomalies.<
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