Towards an ideal world with superconductivity

—Current status and prospects for rare-earth barium copper oxide superconducting tapes—

Abstract

We review the history, current status, and prospects of research on rare-earth barium copper oxide (REBa₂Cu₃O_y) coated conductors. Three major issues were addressed to achieve critical current performance for long-coated conductors of several hundred meters. Special functional performances, e.g., in-field critical current, were greatly improved. Applications of coated conductors were also initiated. We expect applications to appear in the near future.