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In situ epitaxial MgB2 thin films for superconducting electronics

Nature Materials volume 1, pages 35–38 (2002)Cite this article

Abstract

The newly discovered 39-K superconductor MgB21 holds great promise for superconducting electronics. Like the conventional superconductor Nb, MgB2 is a phonon-mediated superconductor2, with a relatively long coherence length3. These properties make the prospect of fabricating reproducible uniform Josephson junctions, the fundamental element of superconducting circuits, much more favourable for MgB2 than for high-temperature superconductors. The higher transition temperature and larger energy gap4,5 of MgB2 promise higher operating temperatures and potentially higher speeds than Nb-based integrated circuits. However, success in MgB2 Josephson junctions has been limited because of the lack of an adequate thin-film technology6,7. Because a superconducting integrated circuit uses a multilayer of superconducting, insulating and resistive films, an in situ process in which MgB2 is formed directly on the substrate is desirable. Here we show that this can be achieved by hybrid physical–chemical vapour deposition. The epitaxially grown MgB2 films show a high transition temperature and low resistivity, comparable to the best bulk samples, and their surfaces are smooth. This advance removes a major barrier for superconducting electronics using MgB2.

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Figure 1: X-ray diffraction spectra of an MgB2 film on a (0001) sapphire substrate showing an epitaxial orientation relationship.
Figure 2: Microstructure and interfacial atomic structure of the same film described in Fig. 1 studied by cross-sectional transmission electron microscopy (TEM).
Figure 3: Superconducting and transport properties of MgB2 thin films.
Figure 4: Surface morphology of the epitaxial MgB2 films.

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References

  1. Nagamatsu, J., Nakagawa, N., Muranaka, T., Zenitani, Y. & Akimitsu, J. Superconductivity at 39 K in magnesium diboride. Nature 410, 63–64 (2001)

    Article  CAS  Google Scholar 

  2. Bud'ko, S. L. et al. Boron isotope effect in superconducting MgB2 . Phys. Rev. Lett. 86, 1877–1880 (2001)

    Article  CAS  Google Scholar 

  3. Finnemore, D. K., Ostenson, J. E., Bud'ko, S. L., Lapertot, G. & Canfield, P. C. Thermodynamic and transport properties of superconducting Mg10B2 . Phys. Rev. Lett. 86, 2420–2422 (2001)

    Article  CAS  Google Scholar 

  4. Tsuda, S. et al. Evidence for a multiple superconducting gap in MgB2 from high-resolution photoemission spectroscopy. Phys. Rev. Lett. 87, 177006 (2001)

    Article  CAS  Google Scholar 

  5. Schmidt, H., Zasadzinski, J. F., Gray, K. E. & Hinks, D. G. Evidence for two-band superconductivity from break-junction tunneling on MgB2 . Phys. Rev. Lett. 88, 127002 (2002)

    Article  CAS  Google Scholar 

  6. Mijatovic, D. et al. Magnesium-diboride ramp-type Josephson junctions. Appl. Phys. Lett. 80, 2141–2143 (2002)

    Article  CAS  Google Scholar 

  7. Carapella, G. et al. Josephson effect in Nb/Al2O3/Al/MgB2 large-area thin-film heterostructures. Appl. Phys. Lett. 80, 2949–2951 (2002)

    Article  CAS  Google Scholar 

  8. Brock, D. K., Track, E. K. & Rowell, J. M. Superconductor ICs: the 100-GHz second generation. IEEE Spectrum 37 (12), 40–46 (2000)

    Article  Google Scholar 

  9. Kleinsasser, A. W. High performance Nb Josephson devices for petaflops computing. IEEE Trans. Appl. Supercond. 11, 1043–1049 (2001)

    Article  Google Scholar 

  10. Blank, D. H. A. et al. Superconducting Mg-B films by pulsed laser deposition in an in-situ two-step process using multi-component targets. Appl. Phys. Lett., 79–81 (2001)

  11. Christen, H. et al. Superconducting magnesium diboride films with T c ≈ 24 K grown by pulsed laser deposition with in-situ anneal. Physica C 353, 157–161 (2001)

    Article  CAS  Google Scholar 

  12. Shinde, S. R. et al. Superconducting MgB2 thin films by pulsed laser deposition. Appl. Phys. Lett. 79, 227–229 (2001)

    Article  CAS  Google Scholar 

  13. Zeng, X. H. et al. Superconducting properties of nanocrystalline MgB2 thin films made by an in situ annealing process. Appl. Phys. Lett. 79, 1840–1842 (2001)

    Article  CAS  Google Scholar 

  14. Ueda, K. & Naito, M. As-grown superconducting MgB2 thin films prepared by molecular beam epitaxy. Appl. Phys. Lett. 79, 2046–2048 (2001)

    Article  CAS  Google Scholar 

  15. Jo, W. et al. Thin film superconducting MgB2 as-grown by MBE without post-anneal. Appl. Phys. Lett. 80, 3563–3565 (2002)

    Article  CAS  Google Scholar 

  16. Kang, W. N., Kim, H.-J., Choi, E.-M., Jung, C. U. & Lee, S.-I. Superconducting MgB2 thin films with a transition temperature of 39 Kelvin. Science 292, 1521–1523 (2001)

    Article  CAS  Google Scholar 

  17. Zhai, H. Y. et al. Growth mechanism of superconducting MgB2 films prepared by various methods. J. Mater. Res. 16, 2759–2762 (2001)

    Article  CAS  Google Scholar 

  18. Eom, C. B. et al. High critical current density and enhanced irreversibility field in superconducting MgB2 films. Nature 411, 558–560 (2001)

    Article  CAS  Google Scholar 

  19. Berenov, A. et al. Growth of strongly biaxially aligned MgB2 thin films on sapphire by postannealing of amorphous precursors. Appl. Phys. Lett. 79, 4001–4003 (2001)

    Article  CAS  Google Scholar 

  20. Lee, S. Y. et al. Significant reduction of the microwave surface resistance of MgB2 films by surface ion milling. Appl. Phys. Lett. 79, 3299–3301 (2002)

    Article  Google Scholar 

  21. Liu, Z. K., Schlom, D. G., Li, Q. & Xi, X. X. Thermodynamics of the Mg-B system: Implications for the deposition of MgB2 thin films. Appl. Phys. Lett. 78, 3678–3680 (2001)

    Article  CAS  Google Scholar 

  22. Kamler, G. et al. Bulk GaN single-crystals growth. J. Crystal Growth 212, 39–48 (2000)

    Article  CAS  Google Scholar 

  23. Canfield, P. C. et al. Superconductivity in dense MgB2 wires. Phys. Rev. Lett. 86, 2423–2426 (2001)

    Article  CAS  Google Scholar 

  24. Ribeiro, R. A., Bud'ko, S. L., Petrovic, C. & Canfield, P. C. Effects of stoichiometry, purity, etching and distilling on resistance of MgB2 pellets and wire segments. cond-mat/0204510.

  25. Jung, M. H. et al. Anisotropic superconductivity in epitaxial MgB2 films. Chem. Phys. Lett. 343, 447–451 (2001)

    Article  CAS  Google Scholar 

  26. Kim, H.-J. et al. High current-carrying capability in c-axis-oriented superconducting MgB2 thin films. Phys. Rev. Lett. 87, 087002 (2001)

    Article  CAS  Google Scholar 

  27. Simon, F. et al. Anisotropy of superconducting MgB2 as seen in electron spin resonance and magnetization data. Phys. Rev. Lett. 87, 047002 (2001)

    Article  CAS  Google Scholar 

  28. Angst, M. et al. Temperature and field dependence of the anisotropy of MgB2 . Phys. Rev. Lett. 88, 167004 (2002)

    Article  CAS  Google Scholar 

  29. Ferdeghini, C. et al. Growth of c-oriented MgB2 thin films by pulsed laser deposition: structural characterization and electronic anisotropy. Supercond. Sci. Technol. 14, 952–957 (2001)

    Article  CAS  Google Scholar 

  30. Bu, S. D. et al. Synthesis and properties of c-axis oriented epitaxial MgB2 thin films. Appl. Phys. Lett. (in the press)

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Acknowledgements

We gratefully acknowledge J. Rowell for discussions on the superconducting digital technologies and comments on the manuscript. We thank A. Soukiassian, S. Raghavan and K-K. Lew for their help in setting up the HPCVD system. This work is supported in part by the Office of Naval Research under grant Nos. N00014-00-1-0294 (XXX) and N0014-01-1--0006 (JMR), by the Naval Science Foundation under grant Nos. DMR-9876266 and DMR-9972973 (QL), DMR-9875405 and DMR-9871177 (XQP) and DMR-9983532 (ZKL) and by the Department of Energy under grant DE-FG02-97ER45638 (DGS).

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Authors and Affiliations

  1. Department of Physics,

    Xianghui Zeng, Alexej V. Pogrebnyakov, Armen Kotcharov, James E. Jones, X. X. Xi, Shengyong Xu & Qi Li

  2. Department of Materials Science and Engineering,

    X. X. Xi, Eric M. Lysczek, Joan M. Redwing, James Lettieri, Darrell G. Schlom & Zi-Kui Liu

  3. Materials Research Institute, The Pennsylvania State University, University Park, Pensylvania, 16802, USA

    X. X. Xi, Joan M. Redwing, Qi Li, James Lettieri, Darrell G. Schlom & Zi-Kui Liu

  4. Department of Materials Science and Engineering, The University of Michigan, Ann Arbor, Michigan, 48109, USA

    Wei Tian & Xiaoqing Pan

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Correspondence to X. X. Xi.

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Zeng, X., Pogrebnyakov, A., Kotcharov, A. et al. In situ epitaxial MgB2 thin films for superconducting electronics. Nature Mater 1, 35–38 (2002). https://doi.org/10.1038/nmat703

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