High-quality as-grown MgB2 thin-film fabrication at a low temperature using an in-plane-lattice near-matched epitaxial-buffer layer.

An as-grown MgB2 crystalline thin film was fabricated at a low temperature of 270°C on an in-plane-lattice near-matched TiZr buffer layer grown on a sapphire Al2O3 (0001) surface. The critical temperature and the superconductivity critical current density of MgB2/TiZr/Al2O3 were found to be high compared with those of MgB2/Al2O3. The film was characterized by using synchrotron x-ray diffraction. The epitaxial relationship in the plane was MgB2[0110]//TiZr[0110]// sapphire [1120]. In-plane-lattice spacings, d//MgB2, d//TiZr, and d//sapphire obtained were 0.268, 0.258, and 0.239 nm for the MgB2(0110), TiZr(0110), and sapphire (1120) planes, respectively. [ABSTRACT FROM AUTHOR]