MM and sub-MM properties of ramp-type Josephson junctions on MgO with STO buffer layers

• Published in: IEEE transactions on applied superconductivity Vol. 9; no. 2; pp. 3854 - 3857
• Main Authors: Myoren, H., Chen, J., Yamashita, T., Amatuni, L., Sonnenberg, A.H., Gerritsma, G.J., Rogalla, H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-06-1999; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Atomic force microscopy; Buffer layers; Chromium nitride; Electronics; Emission; Exact sciences and technology; Fabrication; High temperature superconductors; Irradiation; Josephson junctions; Magnesium oxide; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sputter etching; Sputtering; Strontium titanates; Substrates; Superconducting devices; Superconducting epitaxial layers; Superconductivity; Surface morphology; Buffer layer; Shapiro step; Atomic force microscopy; Millimetric wave; Output power; Voltage current curve; Electrical properties; Josephson junction; Submillimetric wave; High temperature superconductor
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/77.783868

We have successfully fabricated ramp-type junctions on MgO substrates using an SrTiO/sub 3/ (STO) buffer layer. The observed I/sub c/R/sub n/ product for the junctions on MgO with STO buffer layer were about 2 mV at 4.2 K and 0.1 mV at 60 K. The junctions clearly showed Shapiro steps under irradiation of MM-waves and sub-MM-waves. We observed Josephson emission at 50 GHz from a junction on a MgO substrate with STO buffer layer at 17 K. We have also confirmed mixing in the self-oscillating mode using MM-wave and sub-MM-wave signals.