Mechanisms of cation defect formation in epitaxial YBa2Cu3O7-x films

Errors inherent in electron probe microanalysis of YBa2Cu3O7 films and the atomic composition of films with a resolution of 2 mu m have been found. Critical temperature values have been determined from the temperature dependence of the electron beam induced voltage (EBIV), Having plotted these results on a triple phase diagram of oxides, we found two tie lines with highest T-c (ridges) and two tie lines with lowest T-c (valleys). A mechanism of cation defect formation was proposed which accounts for the presence of this topology. The mechanism was verified by reconstructing cation defects observed in TEM images. (C) 1997 Elsevier Science B.V.