Contribution of thermal noise to the line width of Josephson radiation from superconducting point contacts
Contribution of thermal noise to line width of Josephson radiation from superconducting point contacts
Kamper, R. A.↗
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Free energy of Josephson junctions.
Microscopic calculation of barrier free energy of Josephson junctions, discussing validity of tunneling Hamiltonian method
Appelbaum, J. A.↗
Interaction of the AC Josephson current surface plasmons.
LF surface plasmons in tunnel junctions coupling to AC Josephson current, discussing I-V characteristics
Economou, E. N.↗
Interaction of AC Josephson currents with surface plasmons in thin superconducting films.
Josephson currents interaction with LF surface plasmons in superposed thin dielectric and superconducting metal films, noting I-V characteristics
Ngai, K. L.↗
Josephson tunneling through normal metal barriers
Using phase lock techniques to study electrical and magnetic properties of metal superconductor Josephson junctions
Rockefeller, R. R.↗
A thin polymer insulator for Josephson tunneling applications
Josephson junction formation, and chemisorption of organics on Pb surfaces
Wilmsen, C. W.↗
Noise thermometry with the Josephson effect
Noise thermometry by Josephson effect, demonstrating self excitation random frequency modulation with thermal noise and thermometer having microkelvin noise temperature measurement capability
Kamper, R. A.↗
Geometrical dependence of the maximum dc Josephson current
Josephson maximum DC current plot for linear overlap junctions, discussing junction area geometry to current perimetric proportionality
Stuehm, D. L.↗
Three-Josephson-junction interferometer.
An analysis shows that a three-Josephson-junction asymmetric-feed quantum interferometer has increased magnetic field sensitivity and amplitude deviation over those of a two-junction interferometer. The critical current at zero applied field is lower than the critical current at zero flux in the interference loop.
Stuehm, D. L.↗
Critical current periodicity of Josephson junction interferometers.
Numerical calculation of the critical current through a Josephson junction interferometer, taking into consideration the effect of applied and self-induced magnetic fields on the junctions and in the interference loop. The periodicity of the interference pattern is shown to be less than the flux quantum. Quantitative results are given which illustrate the degree of deviation in periodicity from the flux quantum.
Stuehm, D. L.↗
Power flow for Josephson elements.
General relations are presented for the power flow at the frequencies of interest in a Josephson element. These general power flow relations depend upon whether the autonomous frequency is phase-locked, either harmonically or subharmonically, to a frequency in the system or is unlocked. The results presented generalize those given previously by Russer (1971) for the harmonically locked case.
Thompson, E. D.↗
Perturbation theory for a resistivity shunted Josephson element
We present a systematic perturbation theory, extendable in principle to all orders of magnitude, for the solution of the equations of motion of an ideal Josephson element shunted by a resistance and driven by a dc current source and a small time-dependent source. We present second-order results for the case in which the time dependence is that of a single sinusoid, and these results are compared with other numerical and analytical calculations. Near, but not on, the first constant voltage step where the perturbation theory appears divergent, the current-voltage characteristic is calculated by means of a nonperturbative adiabatic procedure. The impedance and responsivity agree with earlier results.
Thompson, E. D.↗
The SNS Josephson junction with a third terminal
Discussion of the operating characteristics of a three-terminal thin-film SNS Josephson junction whose diameter is much greater than the electron pair coherence length in the N metal. It is shown that a junction of this type is essentially a two-terminal device even though the third terminal of the junction supplies the control current. The mechanism underlying this finding is discussed.
Prans, G. P.↗
An investigation of the SNS Josephson junction as a three-terminal device
A particular phenomenon of the SNS Josephson junction was investigated; i.e., control by a current entering the normal region and leaving through one of the superconducting regions. The effect of the control current on the junction was found to be dependent upon the ration of the resistances of the two halves of the N layer. A low frequency, lumped, nonlinear model was proposed to describe the electrical characteristics of the device, and a method was developed to plot the dynamic junction resistance as a function of junction current. The effective thermal noise temperature of the sample was determined. Small signal linearized analysis of the device suggests its use as an impedance transformer, although geometric limitations must be overcome. Linear approximation indicates that it is reciprocal and no power gain is possible. It is felt that, with suitable metallurgical and geometrical improvements, the device has promise to become a superconducting transistor.
Meissner, H.↗
Perturbation treatment of mixing in Josephson junctions
The mixing properties of a current-biased resistively-shunted Josephson junction irradiated at two frequencies are calculated by a perturbation technique, treating both signals as perturbations. The size of the mixing steps is obtained from second-order calculations. It is shown that subharmonic mixing steps are absent in the case of a single frequency. The amplitude of the voltage oscillations at the difference and sum frequencies is shown to be nonzero at all voltages. The microwave resistance is calculated for one frequency to third order in the perturbation.
Levinsen, M. T.↗
Energy storage and subharmonic oscillations in Josephson junctions
The energy stored in the magnetic and electric field near a superconducting point contact is typically the same magnitude as the coupling energy which produces the Josephson effect in the weakly coupled superconductors. One consequence of energy storage in both the electric and magnetic field is that the junction can oscillate at a fundamental frequency. The dynamics of these subharmonic oscillations have been studied for a model in which the magnetic and electric energies are represented as being stored in an inductance and a capacitance respectively. The model was studied numerically for various biasing conditions, and the behavior compared to experimental data. A simple analytic approximation was developed that gives physical insight into the mechanism that creates the subharmonic oscillations.
Dempsey, D. G.↗
Parametric amplification by unbiased Josephson junctions
The theory of parametric amplification by a series of unbiased Josephson junctions is presented. The various regimes of operation are explored. This device is different in many ways from the usual varactor parametric amplifier. In particular, a very small pump power is required, and a large bandwidth is obtained. Comparison with experimental data is made.
Feldman, M. J.↗
Parametric amplification and oscillation at 36 GHz using a point-contact Josephson junction
The paper reports observation of doubly degenerate parametric amplification and oscillation at 36 GHz from a single point-contact Josephson junction. The experimental results agree qualitatively with theoretical calculations based on the resistively shunted junction model. The estimated noise temperature of an amplifier with 11 dB net gain is consistent with zero, but has an upper limit of 50 K. Attempts to observe parametric amplification in the singly degenerate mode with a pump frequency of 72 GHz were not successful.
Taur, Y.↗