Microwave power handling capability of HTS superconducting thin films: weak links and thermal effects induced limitation

Wosik, J.; Xie, Lei; Grabovickic, R.; Hogan, Timothy P.; Long, Stuart A.

doi:10.1109/77.784973

Cited by 29 publications

(18 citation statements)

References 5 publications

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“…The result is (37) Following a similar procedure for modulus nonlinearities (see [7] for a detailed description), and assuming , the result is (38) 2) Dielectric Loaded Cavity With Superconducting Endplates: The analysis and simulation of nonlinearities in cavities with superconducting endplates is also of practical interest since it may provide a way to evaluate nonlinear properties of superconducting films without having to pattern them [10], [13], [30]. An empty cylindrical cavity could in principle be used, but the current densities are too small to produce significant intermodulation fields [31].…”

Section: )mentioning

confidence: 99%

Analysis and Simulation of the Effects of Distributed Nonlinearities in Microwave Superconducting Devices

Collado

Mateu

O'Callaghan

2005

IEEE Trans. Appl. Supercond.

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Abstract-This paper presents a comprehensive study of microwave nonlinearities in superconductors, with an emphasis on intermodulation distortion and third-harmonic generation. It contains the analysis of various resonant and nonresonant test devices and its validation using numerical simulations based on harmonic balance (HB).The HB simulations made on test devices show that the closedform equations for intermodulation and third-harmonic generation are only valid at low power levels.The paper also contains examples of application of HB to illustrate that this technique is useful to simulate superconductive devices other than simple test devices, and that the validity of the simulations is not restricted to low drive power levels.Most of the analyses and simulations of this paper are based on electrical parameters that describe the nonlinearities in the superconducting material. These parameters are compatible with many existing models of microwave nonlinearities in superconductors. We discuss the particulars on how to relate these electrical parameters with one of the existing models that postulates that the nonlinear effects are due to a dependence of the penetration depth on the current density in the superconductor.

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Section: )mentioning

confidence: 99%

Analysis and Simulation of the Effects of Distributed Nonlinearities in Microwave Superconducting Devices

Collado

Mateu

O'Callaghan

2005

IEEE Trans. Appl. Supercond.

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“…6 Quasiparticle heating is sometimes mentioned but neglected due to the relatively high thermal conductivity of high-T c superconductors. Where thermal effects play a role, they are caused by local heating due to film inhomogeneities 8,20 or measured by an external resonant probe. 21 We emphasize that some of these effects may still be present in low-T c resonators but the temperature-state switching described here is likely to dominate at the very low operating temperatures, T c / 10, of KIDs, especially where T c Ϸ 1 -2 K. Another global heating model, based on the substrate thermal conductivity, was previously described.…”

Section: Introductionmentioning

confidence: 99%

Readout-power heating and hysteretic switching between thermal quasiparticle states in kinetic inductance detectors

Visser

Withington

Goldie

2010

Journal of Applied Physics

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A model is presented for readout-power heating in kinetic inductance detectors. It is shown that the power dissipated by the readout signal can cause the temperature of the quasiparticle system in the superconducting resonator to switch between well-defined states. At low readout powers, only a single solution to the heat balance equation exists, and the resonance curve merely distorts as the readout power is increased. At high readout powers, three states exist, two of which are stable, and the resonance curve shows hysteretic switching. The power threshold for switching depends on the geometry and material used but is typically around Ϫ70 dBm for Aluminum resonators. A comprehensive set of simulations is reported, and a detailed account of the switching process is given. Experimental results are also shown, which are in strong qualitative agreement with the simulations. The general features of the model are independent of the precise cooling function, and are even applicable for resonators on suspended, thermally isolated, dielectric membranes, where an increase in quasiparticle lifetime is expected. We discuss various extensions to the technique, including the possibility of recovering the cooling function from large-signal measurements of the resonance curve.

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“…6͑c͒, which represent the case of highest disorder here considered, evidence of weaklink switch to resistive behavior is pointed out by the vertical "steps" in the resonance curves. 39 In previous measurements such weak links could be also present, but they were under critical. As a further element of the discussion, we remind one that in this case the surface residual resistance R res ϰ j cJ −3/2 R bl −1 , where j cJ is the junction critical current density and R bl is the normal leakage current resistance.…”

Section: Resultsmentioning

confidence: 93%

Effects of disorder on the microwave properties ofMgB2polycrystalline films

et al. 2006

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The role of disorder in superconducting magnesium diboride ͑MgB 2 ͒ policrystalline films is investigated in the high frequency range by a coplanar microwave resonator technique. Two sources of disorder are considered, heavy-ion irradiation damage and sample ageing. Microwave measurements are analyzed in the framework of the two-gap model with strong interband scattering contribution. It turns out that disorder enhancement increases the interband scattering rate, resulting in a reduction of the surface resistance at low temperatures, due to a slight increase of the gap. Moreover, increasing disorder at grain boundaries induces a nonmonotonic residual surface resistance, showing the features of a resistive behavior for the highest disorder level. Finally, the effects of the different kinds of disorder on the intrinsic and on the grain-boundary properties of the MgB 2 films are compared and discussed.

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Microwave power handling capability of HTS superconducting thin films: weak links and thermal effects induced limitation

Cited by 29 publications

References 5 publications

Analysis and Simulation of the Effects of Distributed Nonlinearities in Microwave Superconducting Devices

Analysis and Simulation of the Effects of Distributed Nonlinearities in Microwave Superconducting Devices

Readout-power heating and hysteretic switching between thermal quasiparticle states in kinetic inductance detectors

Effects of disorder on the microwave properties ofMgB2polycrystalline films

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