Damping in a superconducting mechanical resonator (original) (raw)
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Damping of vibrations in superconducting quarter wave resonators
Physical Review Accelerators and Beams, 2019
The mechanism of the damper parameters impacting on the maximum cavity detuning at a given excitation is investigated. An analytical model of the damper has been derived to predict the nonlinear response. Numerical results from simulations in ANSYS confirmed the model over a wide range of excitation. An experimental demonstration has been conducted successfully on a test bench. Online measurements taken on the ISAC-II superconducting linac at TRIUMF further verify the analytical model.
Physics Letters A, 2009
Peak amplitude measurements of the fundamental mode of oscillation of a suspended aluminum alloy bar hit by an electron beam show that the amplitude is enhanced by a factor ∼ 3.5 when the material is in the superconducting state. This result is consistent with the cosmic ray observations made by the resonant gravitational wave detector NAUTILUS, made of the same alloy, when operated in the superconducting state. A comparison of the experimental data with the predictions of the model describing the underlying physical process is also presented.
Applied Physics Letters, 2019
Characterizing superconducting microwave resonators with highly dissipative elements is a technical challenge, but a requirement for implementing and understanding the operation of hybrid quantum devices involving dissipative elements, e.g., for thermal engineering and detection. We present experiments on λ/4 superconducting niobium coplanar waveguide resonators, terminating at the antinode by a dissipative copper microstrip via aluminum leads, such that the resonator response is difficult to measure in a typical microwave environment. By measuring the transmission both above and below the superconducting transition of aluminum, we are able to isolate the resonance. We then experimentally verify this method with copper microstrips of increasing thicknesses, from 50 nm to 150 nm, and measure quality factors in the range of 10–67 in a consistent way.
Continuum Mechanics and Thermodynamics
The paper deals with the analysis of an influence of the thermal field and its relaxation properties on the compressional and flexural magnetoelastic waves propagation in a vibrating superconducting layer. The investigations have been confined only to the vortex elastic field in the type-II superconductor. The description is based on the extended thermodynamical model of interactions. Contrary to the existing dynamical descriptions of electromagnetothermoelastic interactions in solids and/or in the magnetic vortex field of elastic character in the type-II superconductor, the influence of the thermal field on the electromagnetoelastic field (or electromagnetoelastic waves in such a medium) has been considered by the use of the effective elastic coefficients dependent on temperature and the relaxation time of the thermal field in low temperatures. Keywords Thermodynamics of superconductors • Magnetic vortex waves • Effective elasticity 1 Introduction Electromagnetothermoelastic (EMTE) coupled interactions occur in many physical systems. They are observed, among others, in solids of different electromagnetic properties such as dielectric, semiconducting and superconducting ones. Particularly, if they take place in low temperatures, the most interesting are materials of superconducting properties. The external magnetic field penetrates the type-II superconductor (SC2) in the form of the Abrikosov vortices (see [2-4]). Around each of them the supercurrent flows so there exist the Lorentz force interactions among them creating an additional mechanical (elastic) field (except for the mechanical one of the superconducting material as itself). Near the lower critical magnetic field intensity limit H c1 , that field has also viscous character. Since the superconductivity occurs in the low temperatures where the thermal field has the relaxation character, the most suitable thermodynamical model is the extended one [8-10] to describe more precisely dynamical interactions and processes in the EMTE field in the SC2 and its vortex field. Communicated by Attila Imre.
Fabrication and Characterization of Superconducting Resonators
Journal of Visualized Experiments, 2016
Superconducting microwave resonators are of interest for a wide range of applications, including for their use as microwave kinetic inductance detectors (MKIDs) for the detection of faint astrophysical signatures, as well as for quantum computing applications and materials characterization. In this paper, procedures are presented for the fabrication and characterization of thin-film superconducting microwave resonators. The fabrication methodology allows for the realization of superconducting transmission-line resonators with features on both sides of an atomically smooth single-crystal silicon dielectric. This work describes the procedure for the installation of resonator devices into a cryogenic microwave testbed and for cool-down below the superconducting transition temperature. The setup of the cryogenic microwave testbed allows one to do careful measurements of the complex microwave transmission of these resonator devices, enabling the extraction of the properties of the superconducting lines and dielectric substrate (e.g., internal quality factors, loss and kinetic inductance fractions), which are important for device design and performance.
A QUALITATIVE OVERVIEW OF THE MECHANISMS OF SUPERCONDUCTIVITY SHAILAJ KUMAR SHRIVASTAVA
The mechanism of superconductivity continues to be one of the most fascinating and challenging topics in condense matter physics. The discovery of high-Tc cuprate superconductors and iron based superconductors has challenged the classical theories of condensed matter physics and opened a new chapter of strongly correlated electron systems. The key question of superconductivity is the nature of mechanism of pairing of carriers. The electron phonon interaction or spin fluctuations are considered to be central to the mechanism of superconductivity. In this article attempt has been made to highlights the brief outcome of various models and theories on the mechanism of superconductivity. I.Introduction Dutch scientist Heike Kammerlingh Onnes [1] discovered that electrical resistance of various metals e.g mercury, lead, tin and many others disappeared when the temperature was lowered below some critical value Tc. Meissner and Oschenfeld [2] observed that when a material is cooled in the presence of a magnetic field, on reaching its superconducting transition temperature (Tc) the magnetic flux is suddenly completely expelled from its interior. It means it exhibits perfect diamagnetism. Gorter [3, 4] put forward the idea of a two fluid model, in which the electron gas within the superconductor has two components. One component has no entropy and carries the supercurrent while the other component has all the entropy and behaves like a normal electron gas. Below the super conducting transition temperature, the superconducting electrons short out the normal electrons so that the electrical resistance is zero. These two features were captured in the equation proposed by London brothers [5], who first realized the quantum character of the phenomenon. Ginzburg and Landau [6] created a theory describing the transition between the superconducting and normal phases. Although the Ginzburg and Landau theory explained the macroscopic properties of superconductors, the microscopic properties remain unsolved. Bardeen, Cooper and Schrieffer created microscopic theory (BCS theory) [7] which describe conventional superconductors in the low temperature and low magnetic field regime. According to BCS theory, the superconductors at below Tc have an energy gap equal to binding energy of the Cooper pair, which dominates the transition temperature. The binding energy of the Cooper pair depends on the density of electron states at the Fermi surface, and on the strength of electron phonon interaction. High temperature superconductors are characterized by a layered two dimensional superconducting condensate and unique features that are very different from conventional superconducting materials. Recent studies [8, 9] reveal that the theoretical explanation for copper and iron superconductors could be the same and could even apply to other materials. The spin fluctuation mechanism of high-Tc superconductivity in copper oxide compound is determined by the high intensity of the antiferromagnetic exchange interaction. According to spin fluctuation mechanism [10], the pairing wave function of cuprate high-Tc superconductor should have d-wave symmetry. But unfortunately, some reports supported the d-symmetry for the high-Tc superconductors whereas others supported the s-symmetry. The survey of the mechanism of superconductivity [11] emphasized that all models used the conception of pairing with the subsequent formation of Bose-Condensate at Tc irrespective of the nature of the resulting attraction.
Nonlinear effects in the theory of superconductivity
Journal of Physics: Conference Series, 2012
It is proposed the non-linear cooperative interaction between the electrons through the vibration states of thermostat (the large system with big degree of freedom). As an example is studied the cooperative interaction between the cooper pairs through the non-linear lattice vibration in single and two-phonon exchange processes between the electrons. In the case of superconductivity phase transition, the cooperative interaction between the carriers in two and single phonon exchange processes depends on the temperature. This temperature dependence of exchange integral between the quasi-particles drastically changes the second order diagram as this is demonstrated in paper . Unlike the approach proposed in papers , in this report it is takes into account the non-linear vibration of thermostat modes (phonon, optical modes etc.). It is observed that this effect influence the temperature dependence of the order parameter in the second order phase transition like superconductivity, super-radiance, ferromagnetism, etc.
Simulation Study of Electronic Damping of Microphonic Vibrations in Superconducting Cavities
Proceedings of the 2005 Particle Accelerator Conference, 2005
Electronic damping of microphonic vibrations in superconducting rf cavities involves an active modulation of the cavity field amplitude in order to induce ponderomotive forces that counteract the effect of ambient vibrations on the cavity frequency. In lightly beam loaded cavities, a reduction of the microphonicsinduced frequency excursions leads directly to a reduction of the rf power required for phase and amplitude stabilization. Jefferson Lab is investigating such an electronic damping scheme that could be applied to the JLab 12 GeV upgrade, the RIA driver, and possibly to energy-recovering superconducting linacs. This paper discusses a model and presents simulation results for electronic damping of microphonic vibrations.
Towards an ideal world with superconductivity
Synthesiology English edition
However, as the energy source shifts from natural gas to shale gas, the price has skyrocketed and has become very expensive, and the supply is becoming unstable. Moreover, since it is ultra-low in temperature, extremely low specific heat is another problem. The heat generated or entered by accidental thermal agitation easily raises the temperature, and the temperature may surpass T c and cause a phenomenon called quench in which superconductivity is rapidly lost. Both are issues that arise from ultra-low temperature, and the discovery of materials that show superconductivity at high temperature was long awaited. As the search continued, J. G. Bednorz and K. A. Müller of Germany discovered a superconductor of a new material with high T c (high-temperature superconductor) in 1986. [2] While the previous superconductors were all metal materials, the material they discovered was an oxide La 2-x Ba x CuO 4. When they found this material, they were not looking for superconductors but were actually in the process of developing a conductor. In this material, the temperature at which zero resistance was reached was about 10 K, and it was not so high compared to the metal materials. Therefore, it did not make news at the time of its discovery. However, Professor Shoji Tanaka of Tokyo University (at the time) focused on the point that the temperature at which the resistance began to fall was over 30 K, and by surveying the materials that had similar composition to this material, he discovered a new superconductor that surpassed the T c limit as predicted by the Bardeen-Cooper-Schrieffer (BCS) theory. [3] Since then, new superconductors were found, and some of them had T c that surpassed the boiling point of liquid nitrogen (77 K), [4]-[6] and there was expectation for wider-ranging applications past the We review the history, current status, and prospects of research on RE Ba 2 Cu 3 O y (RE: rare earth element) coated conductors. Three major issues were addressed to achieve critical current performance for long-coated conductors of several hundred meters. Special functional performances, e.g., in-field critical current, were greatly improved. Applications of coated conductors were also initiated. We expect applications to appear in the near future.