Influences of cooling height and lateral moving speed on the levitation characteristics of YBaCuO bulks

Josephson junction arrays could be competitive candidates for radiation sources in the frequency range from 0.5 to 1.5 THz. This is the range where compact solid-state continuous wave sources are most lacking. We investigated the millimeter-wave radiation from arrays of high-temperature superconductor bicrystal Josephson junctions embedded in a quasi-optical resonator. The novel approach of utilizing the intrinsic resonance modes of the substrate to improve the impedance coupling between the series array of discrete Josephson junctions and the quasi-optical resonator was investigated by experiments and electromagnetic field simulations. Radiation from the arrays containing up to 536 junctions was detected at about 80 GHz and liquid nitrogen temperature using a low-noise receiver. The detected maximum radiation power of the arrays was about 50 pW and the peak voltage agreed exactly with the Josephson current-voltage relation.

Section: Resultsmentioning

confidence: 59%

Millimeter-wavelength radiation from arrays of discrete high-temperature superconductor Josephson junctions

Song

Levitchev

Markelov

et al. 2010

“…Considering the sloping steps shown in figure 7 curve (a), the low value of the self-radiation power and the large width of the radiation peak, we infer that the self-radiation of the junction array was incoherent [1]. Previous research results, including experiments [21][22][23] and theories [24][25][26], have suggested a threshold in the number of biased junctions embedded in a resonant cavity. This threshold must be exceeded to attain coherent self-radiation.…”

Section: Experiments Results and Discussionmentioning

confidence: 74%

A method for self-radiation of Josephson junction arrays

Zhao

Yue

et al. 2010

We proposed a novel approach to self-radiation of Josephson junction arrays. Bicrystal Josephson junction arrays fabricated on a bicrystal substrate were integrated with a half-wavelength dipole array and embedded in a Fabry-Perot resonator. Considered as a dielectric resonator, the substrate could be stimulated to resonate in an appropriate mode at the same frequency as the Fabry-Perot resonator, which realized a coupling between Josephson junctions as well as a coupling between the junctions and microwave structures by means of a resonant interaction between junctions and resonators. Both simulations and experiments were performed. A YBCO bicrystal Josephson junction array with 166 junctions was measured at liquid nitrogen temperature. The maximal self-radiation power of 10 pW was detected at 75.2 GHz, which was in agreement with the simulation results.

“…When the Josephson frequency w J equal to the resonance frequency of the circuit w rc , the oscillations in Josephson junction are tuned to this frequency. This resonance could manifested itself in the current-voltage characteristic (IV-characteristic) in a variety of ways; such as, steps [5,6], or humps and dips [7,8]. LC-shunting leads to a step in the one loop IV-characteristics, when the value of Josephson frequency approaches that of the resonance circuit.…”

Section: Introductionmentioning

confidence: 99%

Modeling of LC-shunted intrinsic Josephson junctions in high-T _c superconductors

Shukrinov

Rahmonov

Kulikov

et al. 2016

Resonance phenomena in a model of intrinsic Josephson junctions shunted by LC-elements (L-inductance, C-capacitance) are studied. The phase dynamics and IV-characteristics are investigated in detail when the Josephson frequency approaches the frequency of the resonance circuit. A realization of parametric resonance through the excitation of a longitudinal plasma wave, within the bias current interval corresponding to the resonance circuit branch, is demonstrated. It is found that the temporal dependence of the total voltage of the stack, and the voltage measured across the shunt capacitor, reflect the charging of superconducting layers, a phenomenon which might be useful as a means of detecting such charging experimentally. Thus, based on the voltage dynamics, a novel method for the determination of charging in the superconducting layers of coupled Josephson junctions is proposed. A demonstration and discussion of the influence of external electromagnetic radiation on the IV-characteristics and charge-time dependence is given. Over certain parameter ranges the radiation causes an interesting new type of temporal splitting in the charge-time oscillations within the superconducting layers.