Epitaxial superconductors on rolling-assisted-biaxially-textured-substrates (RABiTS)

An overview of the fabrication of epitaxial, high-J_c, biaxially aligned YBCO thick films on Rolling-assisted-biaxially-textured-substrates (RABiTS) is provided. The RABiTS technique utilizes standard thermomechanical processing to obtain long lengths of flexible, biaxially oriented substrates with smooth surfaces (rms ∼20 nm). The strong biaxial texture of the metal (in-plane 5-7° FWHM) is conferred to the superconductor by deposition of intermediate metal and/or oxide layers which serve both as a chemical as well as a structural buffer. Epitaxial YBCO films have been grown using a variety of techniques on RABiTSTM with critical current densities exceeding 106 A/cm2 at 77 K in self-field and have field dependences similar to that of epitaxial films on single crystal ceramic substrates. The texture of the base metal has been achieved in kilometer lengths and scaleable techniques are being pursued to deposit the epitaxial multilayers. Deposited conductors made using this technique offer a potential route for the fabrication of long lengths of high J_c wire capable of carrying high currents in high magnetic fields and at elevated temperatures.