High critical current densities (J_c) in thick films of the Y_1Ba_2Cu_3O_(7-δ) (YBCO, T_≈ 92 K) superconductor directly depend upon the types of nanoscale defects and their densities within the films. A major challenge for developing a viable wire technol ogy is to introduce nanoscale defect structures into the YBCO grains of the thick film suitable for flux pinning and the tailoring of the superconducting properties to specific, application-dependent, temperature and magnetic field conditions. Concurrently, the YBCO film needs to be integrated into a macroscopically defect-free conductor in which the grain-to-grain connectivity maintains levels of inter-grain J_c that are comparable to the intra-grain J_c. That is, high critical current (I_c) YBCO coated conductors must contain engineered inhomo-geneities on the nanoscale, while being homogeneous on the macroscale. An analysis is presented of the advances in high-performance YBCO coated-conductors using chemical solution deposition (CSD) based on metal trifluoroa-cetates and the subsequent processing to nano-engineer the microstructure for tuneable superconducting wires. Multi-scale structural, chemical, and electrical investigations of the CSD film processes, thick film development, key microstructural features, and wire properties are presented. Prospects for further development of much higher I_c wires for large-scale, commercial application are discussed within the context of these recent advances.
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