Uniform texture in meter-long YBa₂Cu₃O₇ tape

A reel-to-reel tape handler mounted on a four-circle diffractometer is used to provide a characterization by X-ray diffraction of the entire 1 m length of a YBa₂Cu₃O₇/CeO₂/Y_xZr_{1 -x}O₂/CeO₂/Pd/Ni (YBCO/CeO₂/YSZ/CeO₂/Pd/Ni) tape. Cube-textured Ni was formed by rolling and annealing; epitaxial CeO₂/YSZ/CeO₂/Pd buffer layers were deposited by reactive sputtering; YBCO was converted ex situ from Y, BaF₂, and Cu codeposited by e-beam evaporation. Rocking curve FWHM (mean±standard deviation) for 95 segments of 1 cm length are: YBCO(005)=6.2±0.5°, YSZ(002)=10.4±0.4°, and Ni(002)=7.6±0.3°. φ scan FWHM are: YBCO(113)=9.6±0.4°, YSZ(111)=13.0±0.4°, and Ni(111)=10.6±0.4°. Greater than 95% of the tape at each point is cube textured from Ni to YBCO. The critical current density J_c is 0.36±0.04 MA/cm² at 77 K and is inversely correlated with the rocking curve FWHM. Calculations suggest that J_c might be increased by a factor of 2.1 by producing a sharper texture and that the uniformity of the texture will support scaling to kilometer lengths.