Nb/Al_2O_3/Ni_{0.6}Cu_{0.4}/Nb based superconductor-insulator-ferromagnet-superconductor (SIFS) Josephson tunnel junctions with a thickness step in the metallic ferromagnetic \Ni_{0.6}\Cu_{0.4} interlayer were fabricated. The step was defined by optical lithography and controlled etching. The step height is on the scale of a few angstroms. Experimentally determined junction parameters by current-voltage characteristics and Fraunhofer pattern indicate an uniform F-layer thickness and the same interface transparencies for etched and non-etched F-layers. This technique could be used to tailor low-T_c Josephson junctions having controlled critical current densities at defined parts of the junction area, as needed for tunable resonators, magnetic-field driven electronics or phase modulated devices.
@article{arxiv.cond-mat/0612164,
title = {Low-T_c Josephson junctions with tailored barrier},
author = {M. Weides and C. Schindler and H. Kohlstedt},
journal= {arXiv preprint arXiv:cond-mat/0612164},
year = {2007}
}
Comments
6 pages, 6 figures, small changes, to be published by JAP