3D intrinsic Josephson junctions using c-axis thin films and single crystals

We report successful fabrication of 3D intrinsic Josephson junctions (IJJs) using c-axis YBCO thin films of 800 nm thickness and Bi-2212 single-crystal whiskers. The stacks of IJJs were prepared by a lateral focused ion beam etching method. The width depending on the required junction size and the full depth of film thickness were patterned in a micro area from the normal direction etching. By tilting the sample stage up to 90°, two grooves of the bridge were etched from the lateral direction in accordance with the required junction size. The junctions did not show any degradation of critical current density (J_c) down to an in-plane area of 0.5 µm².