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 temp erature dependence of the electron beam induced voltage (EBIV), Having plotted these results on a triple phase diagram of oxides, we found t wo tie lines with highest T-c (ridges) and two tie lines with lowest T -c (valleys). A mechanism of cation defect formation was proposed whic h accounts for the presence of this topology. The mechanism was verifi ed by reconstructing cation defects observed in TEM images. (C) 1997 E lsevier Science B.V.