D. Neri et al., High frequency resistivity in YBa2Cu3O7-delta: Effects of anisotropic renormalized fluctuations, INT J MOD B, 13(9-10), 1999, pp. 1097-1100
We discuss the excess conductivity above T-c due to renormalized order-para
meter fluctuations in YBCO at microwave frequencies. We show that a phenome
nological cut-off in the fluctuative spectrum can extend the results of the
anisotropic theory of renormalized fluctuations up to the high temperature
region. Measurements of the real part of the microwave resistivity at 24 G
Hz are performed on two YBCO films. The onset of the superconducting transi
tion and the deviation from the linear temperature behavior carl be fully a
ccounted for by the extended theory. Very consistent values of the fundamen
tal parameters (critical temperature, coherence lenghts, penetration depth)
of the superconducting state are obtained.