Preparation, patterning, and properties of thin YBa2Cu3O7−δ films

Abstract

High T_C superconducting thin films were prepared on (100) SrTiO₃ substrates by dc triode sputtering and subsequent annealing. In these films Hall‐bar structures having a width down to 5 μm were patterned using a reactive ion etching technique. Superconductivity above 77 K was observed. When compared with the original film there is only a small reduction in T_C. The critical current density determined by electrical measurements is substantially reduced. On the other hand, the critical current density in the bulk of the grains as measured by the torque on a film is not reduced by the patterning process. It is suggested that superconductor‐normal metal‐superconductor junctions between the grains account for this difference.