Effect of target density on YBCO thin films deposited from nanograined targets

Nanograined YBa2Cu3O6+xYBa2Cu3O6+x (YBCO) targets with grain sizes of 25–45 nm and different densities were prepared with sol–gel method. The properties of the thin films laser deposited from these targets were systematically studied. It was found that most parameters are not clearly affected by the target density, although the surface roughness decreased with target density. A small effect of decreasing JcJc with increasing target density was observed, but this can be interpreted as film to film variation. On the other hand, a negative correlation between the accommodation field, B∗B∗, and zero field JcJc was observed and B∗B∗ was found to increase with increasing number of lattice defects. Thus target density is found not to have a large effects on the superconducting or structural properties of YBCO thin films.