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)
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