Measurement of RF Superconductivity in YBa 2 Cu 3 O 7-x with the Standing-Wave Method at 9 GHz

RF properties of superconducting YBa 2 Cu 3 O 7- x were measured with the standing-wave method in the microwave region. The power absorption (Joule loss) of the powder specimen, calculated from the data of the voltage standing-wave ratio (VSWR), changes markedly at the transition temperature, and decreases with decreasing temperature in the superconducting state. In a lower temperature region, it tends to the formula A=17.6 exp (- 0.031 eV/ kT). Microwaves were found to penetrate considerably into the superconducting specimen.