The transport properties of large-angle grain boundaries containing point defects and charges in YBa2Cu3O7–δ were studied by computer simulation methods. The results of simulation of the atomic structures of large-angle symmetrical tilt grain boundaries Σ5 (misorientation angles 36.87° and 53.13°), Σ13 (misorientation angles 22.62° and 67.38°), Σ17 (misorientation angles 28.07° and 61.93°), and Σ29 (misorientation angle 43.60°) containing point defects (neutral and charged O and Y vacancies) were presented. The techniques of the strain analysis and the bond-valence-sum analysis were applied to determine the thicknesses of non-superconducting layers enveloping these grain boundaries. The data showed that the presence of neutral O vacancies decreased the thicknesses of non-superconducting layers and may improve transport properties of some large-angle grain boundaries. Adsorption capability of grain boundaries with respect to neutral O vacancies was evaluated. Its analysis demonstrated that the tilt grain boundaries in were most probably intrinsically non-stoichiometric.

Transport Properties of Large-Angle Grain Boundaries Containing Point Defects in YBa2Cu3O7–δ. V.S.Boyko, R.Y.Kezerashvili, A.M.Levine: Physical Review B, 2004, 69[21], 212502 (4pp)