Perovskite type buffers for YBCO coated conductors

Coated conductor applications in power technologies require stabilization of the high-temperature superconducting (HTS) layers against thermal runaway. One route to stabilization is through the use of conducting buffer layers that provide good electrical and/or thermal connectivity throughout the laminate structure. Perovskite based conducting oxide buffers such as LaNiO₃ (LNO), SrRuO₃ (SRO), and La_0.7Sr_0.3MnO ₃ (LSMO) have been developed for Rolling-Assisted Biaxially Textured Substrates (RABiTS) approach. Using sputtering, three multi-layer architectures such as SRO/LNO/Ni; LSMO/Ni/Cu; and LSMO/Ir/Ni-W were developed. High J _c YBa₂Cu₃O_7-δ (YBCO) films were grown on these conductive architectures using pulsed laser deposition. Detailed temperature dependent resistivity measurements indicate that YBCO/LSMO/Ir/Ni-W tape is fully conductive. A self-field J_c of 2.2 MA/cm² at 77 K was achieved for this tape. Both cross-sectional TEM and SIMS studies indicated the presence of clean substrate/buffer interface. These results demonstrate that LSMO/Ir multilayers may provide a fully conductive architecture for biaxially textured Cu and/or Cu-alloy substrates.