Growth mechanisms and superconductivity of ultrathin Y1Ba2Cu3O 7−x epitaxial films on (001) MgO substrates - Zhu, S.; Lowndes, D. H.; Chakoumakos, B. C.; Pennycook, S. J.; Zheng, X.-Y.; Warmack, R. J. (American Institute of Physics (AIP), 1993)
http://dx.doi.org/10.1063/1.109072
Keywords: U