Title :
AC Josephson effect in high-Tc polycrystalline thin-film bridges
Author :
Gubankov, V.N. ; Divin, Yu.Ya. ; Kotelyanskii, I.M. ; Kravchenko, V.B.
Author_Institution :
Inst. of Radioeng. of Electron., Acad. of Sci., Moscow, USSR
fDate :
3/1/1991 12:00:00 AM
Abstract :
The effect of millimeter-wave electromagnetic radiation on the I-V curves of superconducting bridges made from polycrystalline YBa2Cu3O7-x films with a grain size of ~1 μm and a critical current density of j c(4.2 K)~104 A/cm2 was investigated. When the bridge dimensions w×1 were decreased from 200×200 μm2 to 5×5 μm2, the effect of radiation at T≪Tc changed from heating (for bridges with w,1⩾100 μm) to vortex synchronization (20 μm<w, 1<100 μm) and after that (w, 1⩽20 μm) to synchronization of Josephson oscillations. Josephson behavior of the bridges with w, 1<20 μm is shown to be related to large-scale percolation processes in the system of intergrain Josephson junctions with a characteristic percolation length of L~20 μm. It is demonstrated that bridges with w, 1<L could have values of noise equivalent power (NEP)<10-12W/Hz1/2 at T=40 K
Keywords :
Josephson effect; barium compounds; high-temperature superconductors; superconducting junction devices; superconducting thin films; yttrium compounds; 1 micron; 20 to 200 micron; 4.2 K; 40 K; AC Josephson effect; EHF; I-V curves; Josephson behavior; MM-waves effect; NEP; bridge dimensions; characteristic percolation length; critical current density; effect of radiation; grain size; heating; high temperature superconductors; high-Tc superconductors; intergrain Josephson junctions; large-scale percolation processes; millimeter-wave electromagnetic radiation; noise equivalent power; polycrystalline YBa2Cu3O7-x films; polycrystalline thin-film bridges; superconducting bridges; synchronization of Josephson oscillations; vortex synchronization; Bridges; Critical current density; Electromagnetic radiation; Grain size; Heating; Josephson effect; Josephson junctions; Large-scale systems; Superconducting device noise; Superconducting films;
Journal_Title :
Magnetics, IEEE Transactions on
