ANISOTROPY AND IMPURITY EFFECT IN HIGH T-C SUPERCONDUCTORS

The impurity effect on both superconducting and normal state propertie s has been investigated to clarify the dimensionality of the one-elect ron state. Our previous study showed that fully oxidized Ba2Y(Cu1-xZnx )(3) O-7-delta (BYCZO) shows essentially three-dimensional (3D) behavi or. This study extends the work toward more two-dimensional materials, namely oxygen-deficient BYCZO and Bi2Sr2Ca(Cu1-xCox)(2)O-8. The elect ronic system of the former stays in 3D, while that of the latter behav es essentially in a 2D manner, suggesting that two-dimensionality is i rrelevant to high Tc superconductivity.