Critical-Current Anisotropy in Superconducting Mb_3Sn Coatings Produced by Electrocodeposition of Nb and Sn

摘要

We report the critical current of superconducting Nb_3Sn coatings produced by electrocodeposition from molten salts and its anisotropy in transverse magnetic fields. The anisotropy is quantified by the ratio of the critical currents measured in magnetic fields parallel and normal to the coating surface, k. The effect of doping with tantalum and nitrogen on the microstructure, critical current, and anisotropy factor A: of Nb_3Sn coatings is examined. The k of the undoped and tantalum-doped coatings ranges from 0.4 to 1.0, and that of the nitrogen-doped coatings, from 0.4 to 1.4. The critical current anisotropy is interpreted in terms of the microstructure of the coatings.