Fabrication and properties of intrinsic Josephson junctions in thin films of Tl-Ba-Ca-Cu-O

We have observed intrinsic Josephson effects for current flow perpendicular to the CuO2 planes in HTSC thin films. TI-Ba-Ca-Cu-O thin films were deposited on step edges in LaAlO3 substrates. Due to the special preparation process, microbridges across such steps act as stacks of intrinsic Josephson junctions with current how perpendicular to the CuO2 planes (STEP STACK junctions). Up to 130 individual junctions could be observed exhibiting high I(C)R(N) products up to 26 mV per junction. We observed ac-Josephson effects as Shapiro steps and in microwave emission experiments. At low temperatures sharp emission peaks were detected at frequencies of 11.3 and 24.2 GHz. Broad emission peaks from the whole stack were observed at temperatures close to T-c. (C) 1996 American Institute of Physics.