Nanocrystalline thin films were prepared on r-cut Al2O3 substrates by annealing multilayer B/Mg precursors in a flow of Mg vapour. The films were highly homogeneous and exhibited a smooth morphology at both the mesoscale and the microscale. The films exhibited a superconducting transition at TC ~35K with a transition width of ~1.2K and a critical current density at 10K in the self-field of JC ~107A/cm2.

Highly Homogeneous MgB2 Films Prepared by a New Post-Annealing Process. A.T.Matveev, J.Albrecht, M.Konuma, B.Stuhlhofer, U.Starke, H.U.Habermeier: Superconductor Science and Technology, 2005, 18, 1313-6