2-DIMENSIONAL BEHAVIOR OF BULK HIGH-TEMPE RATURE SUPERCONDUCTORS

Using the power-law analysis of current-voltage characteristics, the n ew data have been obtained corroborating the realization in granular h igh-T-c samples the two-dimensional behavior with an anomalously large difference between mean-field critical temperature and the temperatur e of Berezinsky-Kosterlitz-Thouless transition. It is shown that such a behavior is due to a small effective thickness of superconducting la yers and their non-perfect attachment in the HTS intergranular boundar ies of metal oxides.