Fabrication of heteroepitaxial Bi/sub 2/(Sr,Ca)/sub 3/Cu/sub 2/O/sub x//Bi/sub 2/Sr/sub 2/CuO/sub y//Bi/sub 2/(Sr,Ca)/sub 3/Cu/sub 2/O/sub x/ Josephson junctions

Abstract

Josephson junctions using c-axis oriented heteroepitaxial Bi/sub 2/(Sr,Ca)/sub 3/Cu/sub 2/O/sub x//Bi/sub 2/Sr/sub 2/CuO/sub y//Bi/sub 2/(Sr,Ca)/sub 3/Cu/sub 2/O/sub x/ trilayer films have been fabricated. The junctions showed the resistively shunted junction-like characteristic up to 50 K. The highest value of the product of the critical current and the normal state resistance of the junctions was about 0.2 mV. Clear Shapiro steps at the expected voltages were observed up to 50 K in the presence of external microwave irradiation. The microwave power dependence of the height of these steps was qualitatively in agreement with the resistively shunted junction model behavior. Moreover, the Fraunhofer-like diffraction pattern in an applied magnetic field was clearly observed. These results indicate that nearly uniform Josephson junctions had been fabricated.< >