Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centres in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa(2)Cu(3)O(7) matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.

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The superconductor industry is demanding new methodologies to manufacture km-long, high quality coated conductors at high growth rates, using cost-effective, scalable processes. We report on the fabrication by an all-chemical deposition method of highly textured, thick (0.9 µm) inkjet-printed YBCO films, using a Ce 0.9 Zr 0.1 O 2 (CZO) capping layer deposited by MOD, on top of robust, buffered ABAD YSZ/SS substrates. Thinner, 0.25 µm spin-coated YBCO films were also analyzed for comparison. The structural study performed by x-ray diffraction, optical, AFM, SEM and TEM microscopy demonstrates the success of the capping layer for enhancing the planarity of the as-received tape and obtaining highly homogeneous and well-textured YBCO films. DC magnetometry granularity analysis was used to determine the mean superconducting grain diameter, ∼2.5 µm, and the intra-and intergranular critical current densities of the coated conductors (CCs). For the thin, spin-coated sample, high self-field intragrain critical currents were measured (J G c = 40, 3.3 MA cm −2 at 5, 77 K). For the thick, inkjet-printed tape J G c was reduced by ∼30%, but, notably, the percolative critical current, J GB c = 12.5 MA cm −2 , was only ∼10% smaller at 5 K, thanks to good preservation of the texture. At 77 K, J GB c = 1.3 MA cm −2 was achieved, implying a critical current of I c = 117 A/cm-width. AC susceptibility measurements allowed us to demonstrate the high homogeneity of the fabricated CCs, and investigate the magnetic vortex-pinning phase diagram. Remarkably, the thick, inkjet-printed sample showed comparable irreversibility line (IL) and activation energy for thermal depinning, U e (H), to the thin sample. The present results open new perspectives for the fabrication of high quality-to-cost ratio, all-chemical CCs with yet higher I c values by inkjet printing multideposition of thicker YBCO layers.

We present the preparation of a new architecture of coated conductor by Inkjet printing of low fluorine YBa 2 Cu 3 O 7-x (YBCO) on top of SuperOx tape: CGO/LMO/IBAD-MgO/Y 2 O 3 /Al 2 O 3 /Hastelloy. A 5-layered multi-deposited, 475 nm thick YBCO film was structurally and magnetically characterized. A good texture was achieved using this combination of buffer layers, requiring only a 30 nm thin IBAD-MgO layer. The LF-YBCO CC reaches self-field critical current density values of J c GB~1 5.9 MA/cm 2 (5 K), ~1.23 MA/cm 2 (77 K) corresponding to an I c (77K)=58.4 A/cm-width. Inkjet printing offers a flexible and cost effective method for YBCO deposition, allowing patterning of structures.