Dissociation of grain boundary dislocations in YBa2Cu3O7-delta-coated conductors

The study reports the discovery of a new structure and spacing versus angle relation for a prevalent type of small-angle grain boundary in YBa2Cu3O7-d elta (YBCO)-coated conductor films. Small-angle [001] tilt grain boundaries with (110) planes exhibit partial grain boundary dislocations (GBDs) separ ated by stacking faults. The dissociated grain boundary structures have twi ce the number of GBDs and shorter interdislocation core channel widths than Frank's geometrical rule predicts. This will require a significant alterat ion of models of supercurrent flow through arrays of small-angle grain boun daries in YBCO coated conductors. A thorough analysis of the stacking fault energy has been conducted based on the basis of anisotropic elasticity.