THE GROWTH TRACE OF SINGLE-DOMAIN YBCO BULK SUPERCONDUCTORS WITH C-AXIS NORMAL TO THE TOP SURFACE

The grown cross traces on the top surface of single-domain YBCO bulk sample with c-axis normal to the top surface has been clearly revealed. It is found that there are many fish-scale like YBCO layers, which are well connected each other. The c-axis is normal to the top surface of the sample, which indicates that YBCO crystal starts to grow from the center to the edge along a(or b) axis in all the four regions divided by across traces, and forms a 90° angle when the four regions meet each other, The clear traces observed is just because of the slightly difference in height between adjacent regions. A simple model has been afforded to explain the growth mechanism of single-domain YBCO bulks with c-axis normal to the top surface.