A cavity system for the measurement of the surface resistance at 48 GHz in high- superconductors

Abstract

We describe a system for the measurement of the surface resistance of high-T c superconductors (HTCSs) at 48 GHz as a function of the temperature, the external magnetic field and its orientation with respect to the crystallographic axes of the sample. The set-up is based upon a resonant cavity. Thin films, bulk ceramics and single crystals can be accommodated in the cavity. A geometry in which there is no c axis microwave current flow, or c axis microwave field penetration, is chosen, so that unwanted effects depending on the anisotropy of HTCSs are ruled out. Geometrical factors for samples smaller than the cavity endplate are calculated. Some measurements on HTCS thin films and single crystals are presented, as well as some of the items of physical information obtainable from the measurements.

Microwave properties of DyBCO monodomain in the mixed state and comparison with other RE-BCO systems

“…In this work, the surface impedance is measured by means of two cylindrical resonators, a silver-coated metal cavity [11] and a dielectric resonator [12], operating in the TE 011 mode at approximately 48.3 GHz and 47.7…”

COMPLEX RESISTIVITY OF YBa2Cu3O7-δ AT 48 GHz IN MAGNETIC FIELDS

“…Calibration of the cavity was used to extract the effective surface resistance R e Jf (iJ, T) of the film. 10 The frequency shift yielded the variation of the effective surface reactance of the film, AXI*f{H,T).…”

Microwave properties of YBa2Cu3O7-δ films: magnetic-field-dependent order parameter fluctuations

“…Microwave currents flowed in the (a,b) plane, so that the in-plane resistivity was measured. Further details on the experimental apparatus and the measurement method have been given elsewhere (Silva et al 1998). The zero-field resistive transition is reported in figure 1.…”