2002/03/29 by S. D. Bu, D. M. Kim, J. H. Choi +13 · 5 citations
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #cond-mat.mtrl-sci #cond-mat.supr-con
paper · pdf · doi:10.1063/1.1504490
10 pages, 6 figures
arxiv created 2002/03/29 · openalex publication_date 2002/08/30 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We report the growth and properties of epitaxial MgB2 thin films on (0001) Al2O3 substrates. The MgB2 thin films were prepared by depositing boron films via radio-frequency (rf) magnetron sputtering, followed by a postdeposition anneal at 850 °C in magnesium vapor. X-ray diffraction and cross-sectional transmission electron microscopy reveal that the epitaxial MgB2 films are oriented with their c-axis normal to the (0001) Al2O3 substrate with a 30° rotation in the (0001) plane with respect to the substrate. The critical temperature was found to be 35 K and the anisotropy ratio, Hc2∥/Hc2⊥, was about 3 at 25 K. The critical current densities at 4.2 and 20 K (at 1 T perpendicular magnetic field) are 5×106 and 1×106 A/cm2, respectively. The controlled growth of epitaxial MgB2 thin films opens a new avenue in both understanding superconductivity in MgB2 and technological applications.