Cube-textured Cu tape is highly desirable as a substrate for practical superconducting wires operating in the liquid nitrogen temperature regions, because not only is Cu a non-ferromagnetic metal, the material cost is also much cheaper than Ni or Ni-based alloys. The primary disadvantage, however, is that Cu has poor resistance to oxidation in an oxygen atmosphere at high temperature during the fabrication of YBCO. We therefore added a Ni overlayer on top of the {100}<001> textured Cu tape by electroplating, to reduce the oxidation rate of the Cu substrate. We successfully obtained biaxially oriented YBCO films with a critical current density (
Jc) over 4.5 MA/cm
2 in a self-field at 77 K on cube-textured Cu tapes using CeO
2/YSZ/CeO
2/Ni buffer layers.
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