Reel-to-reel deposition of epitaxial double-sided MgO buffer layers for coated conductors

• Growth of biaxially textured MgO films on flexible substrates.
• Double-sided IBAD buffer template for the first time.
• Studying the influence of ion energy and film thickness on the texture.
• Demonstrating double-sided YBCO films with overall critical current of 300 A/cm.

We have successfully employed a double-sided process to deposit MgO buffer layers on both sides of amorphous Y2O3 surface for double-sided YBa2Cu3O7 − δ (YBCO) coated conductors (CCs) for the first time, the structure of which is of great prospect to improve the performance and cut the production cost. The biaxial textures of MgO buffer layer are noticeably affected by the ion energy and film thickness, which is demonstrated by X-ray diffraction. The best biaxial texture of double-sided MgO films shows ω-scan of (002) MgO and Φ-scan of (220) MgO yield full width at half maximum values of 4° and 7.8° for one side, respectively, as well as 3.5° and 6.7° for the other side. The subsequent double-sided YBCO films are deposited on the as-prepared MgO template with entire critical current of over 300 A/cm for both sides.