OUT-OF-PLANE QUASI-PARTICLE DYNAMICS OF THE CUPRATE SUPERCONDUCTORS BELOW T-C IN MICROWAVE REGION

We have investigated the anisotropic quasiparticle conductivity in the superconducting state for microwave frequencies in YBa2Cu3O7-delta (Y BCO) and La2-xSrxCuO4 (LSCO) with several hole concentrations. Common features were found for YBCO and LSCO. That is, in underdoped material s, the strong two dimensional nature was found to be retained even bel ow T-c. On the other hand, in optimally doped and overdoped materials, the anisotropy decreases rapidly below T-c. In particular, in YBCO, i t is suggested that the c-axis transport becomes coherent below T-c.