Highly oriented as-deposited superconducting laser ablated thin films of Y1Ba2Cu3O7−δ on SrTiO3, zirconia, and Si substrates

Abstract

KrF excimer laser ablation of an Y₁Ba₂Cu₃O_7−δ pellet in 0.1–0.2 Torr of O₂ ambient was used to deposit thin superconducting films onto SrTiO₃, yttria‐stabilized zirconia (YSZ), and silicon substrates at 600–700 °C. The as‐deposited 1‐μm‐thick films at 650–700 °C substrate temperature were superconducting, without further high‐temperature annealing. All films had a similar T_c onset of ∼92 K but different zero‐resistance T_c of 90, 85, and 70 K for the films on SrTiO₃, YSZ, and Si substrates, respectively. Angular x‐ray diffraction analysis showed that all the films were highly oriented with the c axis perpendicular to their surface. Critical current densities at 77 K were about 40 000 and 10 000 A/cm² for the films on SrTiO₃ and YSZ, respectively. Smooth surface morphology was observed in all films, with occasional defects and cracks in the films on YSZ, which seems to explain the lower critical current in these films.