Title :
MM and sub-MM properties of ramp-type Josephson junctions on MgO with STO buffer layers
Author :
Myoren, Hiroaki ; Chen, J. ; Yamashita, T. ; Amatuni, L. ; Sonnenberg, A.H. ; Gerritsma, G.J. ; Rogalla, H.
Author_Institution :
Res. Inst. of Electr. Commun., Tohoku Univ., Sendai, Japan
fDate :
6/1/1999 12:00:00 AM
Abstract :
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.
Keywords :
high-temperature superconductors; millimetre wave mixers; submillimetre wave mixers; superconducting junction devices; superconducting microwave devices; superconducting mixers; 17 K; 4.2 K; 50 GHz; 60 K; DyBaCuO; HTSC; I-V curves; Josephson emission; MM-wave properties; MgO; MgO substrates; PrBaCuGaO; Shapiro steps under irradiation; SrTiO/sub 3/; SrTiO/sub 3/ buffer layer; THz wave signals; critical current; intrinsic noise; ramp-type Josephson junctions; self-oscillating mode mixing; sub-MM wave properties; Atomic force microscopy; Buffer layers; Fabrication; High temperature superconductors; Josephson junctions; Sputter etching; Sputtering; Substrates; Superconducting epitaxial layers; Surface morphology;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
