Preparation of Thin Films YBaCu(F)O with High Tc and Jc
Thin films of YBaCu(F)O were deposited on (100) SrTiO3 substrates by a three e-gun, multisubstrate, computer-controlled evaporator. Several substrate materials, including MgO, ZrO, and SrTiO3, were studied. Annealed films deposited on SrTiO3 substrates were found to be epitaxial and had the best superconducting properties. Transport measurements on the best films show a sharp resistive transition at a temperature TC(R=0) of 90 K and have critical current densities of 2.9×106 A/cm2 at 4.2 K and 5×104 A/cm2 at 77 K. X-ray diffraction studies reveal that the resulting structure has the a-axis perpendicular to the substrate. SEM micrographs show a morphology consisting of an array of orthogonal, interconnecting bars with well developed junctions. The preparation process, the effects of the substrate, and the correlation between the microstructure and the superconducting properties are discussed.
KeywordsCritical Current Density Superconducting Property Annealed Film Residual Magnetization Barium Oxide
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