VORTEX DYNAMICS AT MICROWAVE-FREQUENCIES IN PATTERNED YBA2CU3O7-DELTATHIN-FILMS

YBa2Cu3O7-delta thin films patterned in the form of a meander line res onant structure, are used as a sensitive probe of vortex dynamics at m icrowave frequencies. The experiments enable highly sensitive measurem ents of the complex microwave surface impedance Z(s)(omega,T,H) of YBa 2CU3O7-delta as a function of applied de magnetic field, temperature, and frequency. The Z(s)(H, T) versus H data yield direct experimental results for the vortex viscosity and pinning force constant, which are compared with microscopic theory. (C) 1995 American Institute of Phys ics.