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摘要
Thick superconducting multilayer architectures consisting of alternate superconducting and superconducting layers DyBCO/YBCO and alternate superconducting and insulating layers YBCO/CuO(Y2O3) are developed on buffered Hastelloy tapes using a metal organic deposition process. It is revealed that multilayer intermittent structures for superconducting layers are effective to avoid the presence of microcracks that occur with increasing thickness, which are frequently observed in monolayer films ofREBa(2)Cu(3)O(7-delta) (REBCO, RE= Y, Gd, or other rare earth elements). This paper shows that the thicknesses of DyBCO/YBCO multilayer films can reach 2.8 mu m with a homogeneous, dense and crack-free surface morphology. The out-plane FWHM of the YBCO (005) peaks and the critical current value reach 1.1 degrees and 365 A/cm (77 K, self-field) for such a thick film consisting of Dy-BCO/YBCO multilayers. It is also revealed that the introduction of a CuO layer is effective to avoid the presence of a-axis grains and voids of the YBCO films, which are frequently observed in multilayer films. Note that the introduction of CuO shows little negative influence on the texture of multilayer structure, especially for the bottom CuO. However, the in-plane texture deteriorates seriously for Y2O3/YBCO/YBCO multilayer film. The critical current density of YBCO films with middle CuO and bottom CuO are 2.0 MA/cm(2) and 2.5 MA/cm(2) (77 K, self-field), respectively. The microstructure optimization including the texture, uniformity, crack, defect, and porosity in the multilayered films is probably the reason for the enhancement of superconducting performance.
- 出版日期2017-6
- 单位上海大学
