10 GHz YBa sub(2)Cu sub(3)O sub(7- delta ) superconducting ring resonators on NdGaO sub(3) substrates

YBa sub(2)Cu sub(3)O sub(7- delta ) thin films were formed on NdGaO sub(3) substrates by laser ablation. Critical temperatures greater than 89 K and critical current densities exceeding 2 x 10 super(6) A cm super(-2) at 77 K were obtained. The microwave performance of films patterned into microstrip ring resonators with gold ground planes was measured. An unloaded quality factor six times larger than that of a gold resonator of identical geometry was achieved. The unloaded quality factor decreased below 70 K for both the superconducting and gold resonators due to increasing dielectric losses in the substrate.