On the anisotropy of the superconducting properties of a heavily cold rolled Cu-20 mass% Nb in situ composite

The superconducting properties of a heavily cold rolled Fibre reinforced Cu-20 mass% Nb in situ composite were studied with special regard to directional anisotropy. The superconducting regime of the composite in the presence of external magnetic fields was investigated and compared to the electromagnetic properties of pure Cu and Nb sheets. It was observed that the critical values of the applied magnetic field and of the current density which limit the superconducting state of the composite are larger parallel to the transverse direction than parallel to the normal direction of the rolled composite. The observations are interpreted in terms of the microstructural anisotropy of the Nb filaments after cold rolling.