Effect of the grooved SrTiO3 bicrystal line on the YBa2Cu3O7 grain boundary

Using atomic force microscope (AFM), we have investigated the correlation b etween the characteristics of grooved SrTiO3 (STO) bicrystal line and the g rain-boundary (GB) microstructure of the YBa2Cu3Oy (YBCO) film. When the un derlying groove becomes deeper and steeper, the density of growth spirals a long the boundary line increases and the meandering configuration of GB gra dually disappears. From the measured signals of the dc-SQUIDs patterned on the films, we also conclude that the homogeneity of the GB is improved. (C) 2000 Elsevier Science B.V. All rights reserved.