Off-axis laser deposition of YBa2Cu3O7−δ thin films

Abstract

We report on YBa2Cu3O7−δ thin-film preparation by a new laser deposition geometry, the so-called off-axis laser deposition. Combined with radiation-based substrate heating, this results in c-axis oriented, epitaxial YBa2Cu3O7−δ thin films with critical current densities above 106 A/cm2 at 77 K and zero field and an exceptionally good surface quality, with complete absence of the otherwise observed laser droplets. As proved by atomic force microscopy, the surface roughness is <80 Å over an area of at least 10×10 μm2. Using this off-axis geometry it is possible to coat both sides of a substrate simultaneously, providing a one-step process in double-sided thin-film deposition. Both YBa2Cu3O7−δ films on the substrate show identical superconducting properties.