Development of Fluorine-Free MOD REBCO Tape With BaHfO₃ Artificial Pinning Centers

We fabricated REBCO films with BaHfO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (BHO) artificial pinning centers by the Fluorine-Free MOD (FF-MOD) method on IBAD tapes. While it is known that <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$J_{c}$</tex-math></inline-formula> decreases as the misalignment angle increases, a high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> of more than 500 A/4 mm-width at 77 K, self-field was obtained on the CeO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer with Δ<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">φ</i> of a wide range up to 7.5 degrees. The Δ<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">φ</i> of REBCO decreased sharply with the REBCO thickness up to 0.35 μm, suggesting that texture improvement occurred during the crystal growth of FF-MOD films, which contributed to the high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula>. The in-field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> of REBCO with BHO was enhanced with increasing BHO content, and 171 A/4 mm-width at 20 K under 18 T was achieved. REBCO tapes over 200 m-long with 2.7 mol% BHO were fabricated, and no significant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> drop was observed and a high average <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$I_{\mathrm{c}}$</tex-math></inline-formula> of 467 A/4 mm-width at 77 K, self-field was obtained. These results show the great potential of FF-MOD tape in low-cost commercial applications.