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In situ epitaxial MgB2 thin films for superconducting electronics

X. H. Zeng·A. V. Pogrebnyakov·A. Kotcharov·J. E. Jones·X. X. Xi·E. M. Lysczek·J. M. Redwing·S. Y. Xu·Qi Li·J. Lettieri·D. G. Schlom·W. Tian·X. Q. Pan·Z. K. Liu
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Abstract

A thin film technology compatible with multilayer device fabrication is critical for exploring the potential of the 39-K superconductor magnesium diboride for superconducting electronics. Using a Hybrid Physical-Chemical Vapor Deposition (HPCVD) process, it is shown that the high Mg vapor pressure necessary to keep the MgB$_2$ phase thermodynamically stable can be achieved for the {\it in situ} growth of MgB$_2$ thin films. The films grow epitaxially on (0001) sapphire and (0001) 4H-SiC substrates and show a bulk-like $T_c$ of 39 K, a $J_c$(4.2K) of $1.2 \times 10^7$ A/cm$^2$ in zero field, and a $H_{c2}(0)$ of 29.2 T in parallel magnetic field. The surface is smooth with a root-mean-square roughness of 2.5 nm for MgB$_2$ films on SiC. This deposition method opens tremendous opportunities for superconducting electronics using MgB$_2$.

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X. H. Zeng, A. V. Pogrebnyakov, A. Kotcharov, J. E. Jones, X. X. Xi, E. M. Lysczek, J. M. Redwing, S. Y. Xu, Qi Li, J. Lettieri, D. G. Schlom, W. Tian, X. Q. Pan, Z. K. Liu. 2002-03-27. In situ epitaxial MgB2 thin films for superconducting electronics. https://doi.org/10.1038/nmat703

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