共查询到20条相似文献,搜索用时 78 毫秒
1.
《中国物理 B》2019,(6)
We report the circuit simulations and experiments of millimeter-wave radiation from a high temperature superconducting(HTS) bicrystal Josephson junction(BJJ) array. To study the effects of junction characteristic parameters on radiation properties, new radiation circuit models are proposed in this paper. The series resistively and capacitively shunted junction(RCSJ) models are packaged into a Josephson junction array(JJA) model in the simulation. The current-voltage characteristics(IVCs) curve and radiation peaks are simulated and analyzed by circuit models, which are also observed from the experiment at liquid nitrogen temperature. The experimental radiation linewidth and power are in good agreement with simulated results. The presented circuit models clearly demonstrate that the inconsistency of the JJA will cause a broad linewidth and a low detected power. The junction radiation properties are also investigated at the optimal situation by circuit simulation. The results further confirm that the consistent JJA characteristic parameters can successfully narrow the radiation linewidth and increase the power of junction radiation. 相似文献
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通过超低温实验直接测量了制备的全铌Josephson结的电压源驱动RCSJ模型的I-V特性曲线。建立了Josephson结在电路仿真软件EWB中的模型,极大的方便了Josephson结及相关电路的仿真研究。利用这一新模型对Josephson结的基本特性进行了较为系统的研究,包括RSJ模型和RCSJ模型的直流驱动I-V特性曲线。 相似文献
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在SrTiO3(STO)基片上制作了Tl-2212双晶约瑟夫森结,并对其进行了微波辐照下的I-V特性测试,观察到了夏皮罗台阶,符合约瑟夫森电压-频率关系.利用数值仿真对约瑟夫森结建立了RCSJ模型,仿真结果与实验数据符合较好,利用此模型深入研究了噪声对结动态特性的影响,解释了噪声影响下结的微波感应台阶幅度减小和极小值展宽现象,提出了有效噪声温度为工作温度和外部噪声的等效温度之和.
关键词:
RCSJ模型
噪声
Tl-2212双晶约瑟夫森结 相似文献
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J. E. Marchese M. Cirillo N. Grønbech-Jensen 《The European physical journal. Special topics》2007,147(1):333-342
We investigate the results of recently published experiments on the quantum
behavior of Josephson circuits in terms of the classical modeling based on
the resistively and capacitively-shunted (RCSJ) junction model. Our analysis
shows evidence for a close analogy between the nonlinear behavior of a
pulsed microwave-driven Josephson junction at low temperature and low
dissipation and the experimental observations reported for the Josephson
circuits. Specifically, we demonstrate that Rabi-oscillations,
Ramsey-fringes, and spin-echo observations are not phenomena with a unique
quantum interpretation. In fact, they are natural consequences of transients
to phase-locking in classical nonlinear dynamics and can be observed in a
purely classical model of a Josephson junction when the experimental recipe
for the application of microwaves is followed and the experimental detection
scheme followed. We therefore conclude that classical nonlinear dynamics can
contribute to the understanding of relevant experimental observations of
Josephson response to various microwave perturbations at very low
temperature and low dissipation. 相似文献
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Frequency-domain based methods are not valid to analyze a nonlinear microwave circuit with general, arbitrary nonlinearities. Therefore, analysis of nonlinear microwave circuits in time-domain is presented. Subharmonics and instabilities can be predicted. As examples, Josephson junction and the Schottkybarrier mixer diode are discussed. 相似文献
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Grønbech-Jensen N Castellano MG Chiarello F Cirillo M Cosmelli C Filippenko LV Russo R Torrioli G 《Physical review letters》2004,93(10):107002
We investigate, by experiments and numerical simulations, thermal activation processes of Josephson tunnel junctions in the presence of microwave radiation. When the applied signal resonates with the Josephson plasma frequency oscillations, the switching current may become multivalued in a temperature range far exceeding the classical to quantum crossover temperature. Plots of the switching currents traced as a function of the applied signal frequency show very good agreement with the functional forms expected from Josephson plasma frequency dependencies on the bias current. Throughout, numerical simulations of the corresponding thermally driven classical Josephson junction model show very good agreement with the experimental data. 相似文献
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Y.H. Kim J.H. Kang J.M. Lee T.S. Hahn S.S. Choi S.J. Park 《Physica C: Superconductivity and its Applications》1997,280(4):304-310
As the operating temperature of the SFQ logic circuits gets higher by using high-Tc superconductors, the effect of noise on switching a Josephson junction to the voltage state becomes more important. In this paper, we report our work on high-Tc SFQ RS flip-flop which was made with YBCO thin film deposited on a SrTiO3 bi-crystal. The circuit operated correctly at 71 K over the 200 computer-generated clock cycles without making errors, where a reset or a set operation was made over one clock cycle. Good agreement between the measured data and the calculation based on the thermal activation theory was obtained. The effective noise temperature used to fit the data was much higher than the physical temperature. This could be due to the instrument noise. Improvement in the measurement set-up might reduce the effective noise temperature. Also our measurement results indicate that the elevation of the operating temperature near the liquid nitrogen temperature may not affect the margin of the circuit. 相似文献
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E. V. Il’ichev 《Physics of the Solid State》2016,58(11):2160-2164
The possibility of the implementation of a single-photon detector in the microwave range has been discussed. It has been shown that, for these purposes, it is possible to use an unshunted Josephson junction, which is switched from the superconducting state into a finite-voltage state at the presence of an external signal. The sensitivity of this detector is determined by the distribution of switchings in the absence of an external signal. It has been demonstrated that there is a Josephson junction with a noise temperature below 60 mK at a nominal external temperature of 10 mK. A specific detector intended for the measurement of external microwave signals has been proposed, designed, and fabricated. The first experimental results have been presented. 相似文献
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The equivalent parameters of a Josephson junction in a microwave SQUID structure are calculated on the basis of relations
obtained as a result of an analysis of the operation of an rf SQUID. This analysis is based on the sawtooth variation of the
voltage on the resonator as a function of the constant flux bias. The quantitative characteristics permit regarding the Josephson
junction as a linear impedance in the rf or microwave circuit, whose real and imaginary parts are controlled by the constant
magnetic flux passing through the SQUID loop.
Zh. Tekh. Fiz. 69, 106–112 (November 1999) 相似文献
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Dependences of the microwave absorption on temperature, magnetic field and microwave power obtained for the high-T c superconductors are presented. Shape of the magnetically modulated microwave absorption, low-field phase diagram and overheating of the Josephson junction system induced by microwave irradiation are discussed. The model of the Josephson junction system interacting with microwaves has been used to explain the behavior of the high-T c superconductors in low magnetic field. 相似文献
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M. Siegel E. Heinz P. Seidel V. Hilarius 《Zeitschrift für Physik B Condensed Matter》1991,83(3):323-326
We have investigated dc and ac Josephson effects on YBa2Cu3O7–x ceramic samples using the break junction technique. The critical current was measured as a function of external magnetic field and temperature. The field dependence shows superposition effects of junction and SQUID behavior. The critical current depends linearly on temperature like for SNS junctions. We observed Shapiro steps with microwave radiation with a frequency of 35 GHz at 4.2 K and 77 K, respectively. Deviations of the step height from Bessel behavior at low microwave power are explained within the Stewart-McCumber model using small capacitances of the junction in simulation calculations. 相似文献
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Using a quantum detector, a superconductor-insulator-superconductor junction, we probe separately the emission and absorption noise in the quantum regime of a superconducting resonant circuit at equilibrium. At low temperature the resonant circuit exhibits only absorption noise related to zero point fluctuations, whereas at higher temperature emission noise is also present. By coupling a Josephson junction, biased above the superconducting gap, to the same resonant circuit, we directly measure the noise power of quasiparticles tunneling through the junction at two resonance frequencies. It exhibits a strong frequency dependence, consistent with theoretical predictions. 相似文献
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Nguyen F Boulant N Ithier G Bertet P Pothier H Vion D Esteve D 《Physical review letters》2007,99(18):187005
The voltage oscillations which occur in an ideally current-biased Josephson junction were proposed to make a current standard for metrology. We demonstrate similar oscillations in a more complex Josephson circuit derived from the Cooper pair box: the quantronium. When a constant current I is injected in the gate capacitor of this device, oscillations develop at the frequency f(B)=I/2e, with e the electron charge. We detect these oscillations through the sidebands induced at multiples of f(B) in the spectrum of a microwave signal reflected on the circuit, up to currents I exceeding 100 pA. We discuss the potential interest of this current-to-frequency conversion experiment for metrology. 相似文献
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The escape of a current-biased Josephson tunnel junction from the zero-voltage state in the presence of weak microwave radiation is investigated experimentally at low temperatures. The measurements of the junction switching current distribution indicate the macroscopic quantum tunneling of the phase below a crossover temperature of T small star, filled approximately 280 mK. At temperatures below T small star, filled we observe both single-photon and multiphoton transitions between the junction energy levels by applying microwave radiation in the frequency range between 10 and 38 GHz to the junction. These observations reflect the anharmonicity of the junction potential containing only a small number of levels. 相似文献
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K. Yu. Platov A. M. Klushin M. Yu. Kupriyanov M. Siegel 《Physica C: Superconductivity and its Applications》2001,350(3-4):302-308
A new coupling scheme of the external microwave signal for a digital-to-analog converter based on series arrays of high-temperature superconducting Josephson junctions has been proposed. It is suggested to couple the meander-like array inductively to a parallel microwave transmission line. Within the resistively shunted junction model different types of microwave coupling structures were analyzed with the goal to reduce the mutual phase locking and to achieve high output power and phase-locking stability. A harmonic balance technique was used to derive an analytic expression connecting the amplitudes of microwave voltages and currents in the array and the frequency of the external signal. Numerical simulations were performed to determine the boundaries of stable locking as a function of circuit parameters. 相似文献