Clean epitaxial MgB2 films fabricated by the exsitu annealing of chemical vapour deposition-grown B films in Mg vapour - Hanna, Mina; Wang, Shufang; Eck, Andrew David; Wilke, Rudeger H T; Chen, Ke; Soukiassian, Arsen; Lee, Che-Hui; Dai, Wenqing; Li, Qi; Redwing, Joan M; Schlom, Darrell G; Xi, X X; et al. (Superconductor science & technology, 2008)