Paramagnetic substrates for thin film superconductors: Ni–W and Ni–W–Cr

To avoid ferromagnetic hysteresis losses in alternating current applications of thin film superconductors, paramagnetic substrates are required at 77 K, the operating temperature of the superconducting YBa2Cu3O7−x. Therefore the composition is modified starting from Ni5W to reduce the ferromagnetic Curie temperature. This temperature can be suppressed well below 77 K by adding Cr or further W to the alloys. It is shown that the Ni–W–Cr tapes can be processed, leading to at least 90% cube texture.