Fabrication of Bi2Sr2Ca1Cu2O8+δ/Bi2Sr2Nd1Cu2O8+δ/Bi2Sr2Ca1Cu2O8+δ Josephson Junctions

Abstract
Sandwich-type Josephson junctions using Bi-based oxide barriers were successfully fabricated. Bi2Sr2Ca1Cu2O8+δ films were used for superconducting electrodes, and Bi2Sr2Nd1Cu2O8+δ films were used for the barrier layers. Each material had the same crystalline structure. The resistivity values of the Bi2Sr2Nd1Cu2O8+δ films were rather high compared to those of ordinary metals or Bi2Sr2Cu1O6+δ. The junctions clearly exhibited S/N/S-type characteristics. We observed the ac Josephson effect on the I-V curves under the irradiation of microwaves around 12 GHz.