Grain boundary networks in high-performance,heteroepitaxial, YBCO films on polycrystalline,cube-textured metals |
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| Authors: | A Goyal DP Field R Held J Mannhart |
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| Institution: | 1. Materials Science &2. Technology Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831-6116, USA goyala@ornl.gov;4. School of Mechanical and Materials Engineering , Washington State University , Pullman, WA 99164, USA;5. Experimentalphysik VI, Center for Electronic Correlations and Magnetism , University of Augsburg , 86135 Augsburg, Germany |
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| Abstract: | Grain boundaries (GBs) in high-temperature superconductors suppress the critical current density (J c) dramatically, with the J c decreasing exponentially with GB angle, especially when GB misorientation exceeds 4°. To reduce the number of high-angle GBs, fabrication of biaxially textured, superconducting wires via heteroepitaxial growth on cube-textured metals has been widely investigated worldwide. Such wires exhibit very high J c in applied magnetic fields despite having a majority of GBs with total misorientations in the range 4–8°. Here, we show that GB networks in these wires have numerous GBs with out-of-plane misorientations greater than 4° but few boundaries having in-plane misorientations greater than 4°. Transport measurements on bicrystal GBs show that GBs with out-of-plane tilts between 4° and 8° are well linked. Together, these results explain the high performance of superconducting films on cube-textured metals. |
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| Keywords: | grain boundaries grain boundary interfaces grain boundary engineering |
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