YBa2Cu3O7−δ films on Si with Y-stabilized ZrO2 and Y2O3 buffer layers: High-resolution electron microscopy of the interfaces

The interfaces of YBa2Cu3O7−δ (YBCO) thin films grown on Si substrates with Y-stabilized ZrO2 (YSZ) and Y2O3 buffer layers have been studied by high-resolution electron microscopy. At the Si-YSZ interfaces a 4-nm-thick amorphous silica layer is found, bridged by 10-nm-wide crystalline YSZ regions. Close to these regions the Si substrate contains planar {111} faults. At the YSZ-Y2O3 interfaces perfect misfit dislocations are present, with Burgers vector 1/2〈110〉. They occur either as separated single dislocations or as separated groups of closely spaced dislocations. The atomic coordination at the planar and atomically sharp Y2O3-YBCO interface could be revealed. The first atomic layer of the YBCO is found to be a Ba layer.