Complex microwave conductivity of YBa2Cu3O 7 in magnetic fields up to 500T

摘要

We have measured the complex conductivity of thin films of YBa2cu 3O7 (YBCO) superconductor down to temperatures of 4K and magnetic fields up to 500T. The highly oriented films were probed by 94 GHz radiation, with the external magnetic field applied perpendicular to the c-axis. These measurements allowed us to assign a value of 340 (plus minus) 40 for the upper critical field at T=O. The measurements were recently carried out at the pulsed field facility of the National High Magnetic Field Laboratory at Los Alamos using both Russian and American magnetic flux compression generators.