Title :
Measurement of the surface resistance of YBa2Cu3 O7-δ by the use of a coaxial resonator
Author :
Woodall, P. ; Lancaster, M.J. ; Maclean, T.S.M. ; Gough, C.E. ; Alford, N. McN
Author_Institution :
Sch. of Electron. & Electr. Eng., Birmingham Univ., UK
fDate :
3/1/1991 12:00:00 AM
Abstract :
The design and initial testing of a coaxial cavity for microwave surface resistance (Rs) measurements on high-temperature superconductors are described. The cavity design is optimized so as to produce the maximum number of harmonic measurements using TEM (transverse electromagnetic modes), in order for accurate measurements of Rs versus frequency to be made. Results for Rs using 17 harmonics in the frequency range 1-20 GHz are presented. Initial measurements of the field dependence of Rs are also given. The results show that the frequency dependence of the ceramic material´s Rs is not ω2, as expected from BCS (Bardeen-Cooper-Schrieffer) and the London model. The results also show that Rs is dependent on even very-low-RF magnetic fields. There have been a number of possible explanations for this deviation from the BCS or London theories of Rs
Keywords :
barium compounds; high-temperature superconductors; surface conductivity; yttrium compounds; 1 to 20 GHz; TEM; YBa2Cu3O7-δ; coaxial cavity; coaxial resonator; field dependence; harmonic measurements; high temperature superconductor; microwave surface resistance; surface resistance; transverse electromagnetic modes; Coaxial components; Design optimization; Electrical resistance measurement; Electromagnetic measurements; Frequency measurement; High temperature superconductors; Magnetic field measurement; Microwave measurements; Surface resistance; Testing;
Journal_Title :
Magnetics, IEEE Transactions on
