Microwave resonators from YBa2Cu3O7−δ thin films made by plasma‐enhanced metalorganic chemical vapor deposition

Epitaxial YBa2Cu3O7−δ thin films on LaAlO3 deposited by plasma‐enhanced metalorganic chemical vapor deposition were tested in a 100 GHz microwave cavity and as patterned 5.6 GHz resonators. Two films, both having high critical temperature (≳90 K) and high critical current density (≳106 A/cm2), exhibited low‐power Q’s of 5400 and 8000 as 5.6 GHz microstrip resonators when operated at 77 K. The equivalent surface resistances at 10 GHz are 1.7 and 1 mΩ, respectively. Despite the fact that these films are thinner than typical laser ablation films, the results are within a factor of 2 of the best laser ablation prepared YBa2Cu3O7−δ films.