Nanoscale Texture and Microstructure in NdFeAs(O,F)/IBAD-MgO Superconducting Thin Film with Superior Critical Current Properties
| Autor: | Guo, Zimeng, Gao, Hongye, Kondo, Keisuke, Hatano, Takafumi, Iida, Kazumasa, Hänisch, Jens, Ikuta, Hiroshi, Hata, Satoshi |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | ACS Appl. Electron. Mater., 3, 7 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1021/acsaelm.1c00364 |
| Popis: | This paper reports the nanoscale texture and microstructure of a high-performance NdFeAs(O,F) superconducting thin film grown by molecular beam epitaxy on a textured MgO/Y$_2$O$_3$/Hastelloy substrate. The NdFeAs(O,F) film forms a highly textured columnar grain structure by epitaxial growth on the MgO template. Although the film contains stacking faults along the $ab$-plane as well as grain boundaries perpendicular to the $ab$-plane, good superconducting properties are measured: a critical temperature, $T _{\rm c}$, of 46 K and a self-field critical current density, $J_{\rm c}$, of $2 \times 10^6 \,{\rm A/cm^2}$ at 4.2 K. Automated crystal orientation mapping by scanning precession electron diffraction in transmission electron microscopy is employed to analyze the misorientation angles between adjacent grains in a large ensemble (247 grains). 99% of the grain boundaries show in-plane misorientation angles ($\Delta \gamma$) less than the critical angle $\theta_{\rm c}$, which satisfies one of the necessary conditions for the high $J_{\rm c}$. Comparing the columnar grain size distribution with the mean distance of the flux line lattice, the triple junctions of low-angle grain boundaries are found to be effective pinning centers, even at high temperatures ($\ge$35 K) and/or low magnetic fields. Comment: Main text with Supplement Material, 32 pages, 16 figures |
| Databáze: | arXiv |
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