Fabricating High-Performance MOD-Derived YBa₂Cu₃O_7-δ Layers Over 4 µm via a Novel Semi-Growth Approach

This study investigates an effective method for preparing high-performance YBa₂Cu₃O_7-δ (YBCO)-coated conductors with thick superconducting layers using a semi-growth strategy on a metal–organic decomposition (MOD) industrial production line. The performance results demonstrate that the semi-growth method offers considerable advantages in terms of the film growth quality and high performance owing to the systematic design of a reserved layer, compared to the performance of 2L+L/2L+2L (semi-growth) YBCO thick tapes of varying thicknesses. The 2L+2L thick films over 3.5 µm achieve a critical current (I_c) of 1150 A/12 mm-width (i.e., 958 A/cm-w) at 77 K@self-field, almost double that of conventional 2L (1.6 µm) YBCO tapes, as well as the in-field performance at low temperature. Although the I_c performance decreases when the film thickness increases to 4.2 µm in 2L+2L mode, the overall trend still demonstrates considerable potential for thick-film fabrication. High-performance YBCO tapes have been successfully scaled to the industrial production of hundreds of meters, showcasing broad application prospects and significant scientific value.