Nonlinear Meissner effect in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Nb</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mi>Sn</mml:mi></mml:mrow></mml:math>
 coplanar resonators

Makita, Junki; Sundahl, C.; Ciovati, Gianluigi; Eom, C. B.; Gurevich, A.

doi:10.1103/physrevresearch.4.013156

Cited by 7 publications

(4 citation statements)

References 46 publications

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“…( 8) and β (T ) is the quadratic prefactor. Ginzburg-Landau theory provides an analytical expression for the prefactor β (T → T c ), which depends only on the Ginzburg-Landau parameter κ (defined as λ /ξ for T → T c ) via the following relation 70,71 :…”

Section: /18mentioning

confidence: 99%

Depth-resolved Characterization of Meissner Screening Breakdown in Surface Treated Niobium

Thoeng,

Asaduzzaman,

Kolb

et al. 2024

Preprint

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We report direct measurements of the magnetic field screening at the limits of the Meissner phase for two superconducting Nb samples. The samples are processed with two different surface treatments that have been developed for superconducting radio-frequency cavity applications — a “baseline” treatment and an oxygen-doping (“O-doping” ) treatment. The measurements show: 1) that the screening length is significantly longer in the “O-doping” sample compared to the “baseline” sample; 2) that the screening length near the limits of the Meissner phase increases with applied field; 3) the evolution of the screening profile as the material transitions from the Meissner phase to the mixed phase; and 4) a demonstration of the absence of any screening profile for the highest applied field, indicative of the full flux entering the sample. Measurements are performed utilizing the β -detected nuclear magnetic resonance (β -NMR) technique that allows depth resolved studies of the local magnetic field within the first 100 nm of the surface. The study takes advantage of the β -SRF beamline, a new facility at TRIUMF, Canada, where field levels up to 200 mT are available parallel to the sample surface to replicate radio frequency (RF) fields near the Meissner breakdown limits of Nb.

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Section: /18mentioning

confidence: 99%

Depth-resolved Characterization of Meissner Screening Breakdown in Surface Treated Niobium

Thoeng,

Asaduzzaman,

Kolb

et al. 2024

Preprint

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“…The kinetic inductance can increase greatly in polycrystalline films with weak-linked grain boundaries, particularly granular Al films which have been used in transmons and photon detectors [193][194][195]. Weakly-coupled grain boundaries characteristic of polycrystalline Nb 3 Sn [54][55][56] can increase L k and amplify the nonlinear Meissner effect in Nb 3 Sn coplanar thin film resonators [196]. Here, a polycrystalline film can be regarded as a network of weakly-coupled planar Josephson junctions, each of which adds a nonlinear kinetic inductance L J = ϕ 0 /2π I c cos χ inversely proportional to the tunneling Josephson critical current I c and dependent on the superconducting phase difference χ on the junction [197].…”

Section: Tuning the Kinetic Inductance By The Proximity Effectmentioning

confidence: 99%

Tuning microwave losses in superconducting resonators

Gurevich

2023

Supercond. Sci. Technol.

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Performance of superconducting resonators, particularly cavities for particle accelerators and micro cavities and thin film resonators for quantum computations and photon detectors has been improved substantially by recent materials treatments and technological advances. As a result, the niobium cavities have reached the quality factors $Q\sim 10^{11}$ at 1-2 GHz and 1.5 K and the breakdown radio-frequency (rf) fields $H$close to the dc superheating field of the Meissner state. These advances raise the question whether the state-of-the-art cavities are close to the fundamental limits, what these limits actually are, and to what extent the $Q$ and $H$ limits can be pushed by the materials nano structuring and impurity management. These issues are also relevant to many applications using high-Q thin film resonators, including single-photon detectors and quantum circuits. This topical review outlines basic physical mechanisms of the rf nonlinear surface impedance controlled by quasiparticles, dielectric losses and trapped vortices, as well as the dynamic field limit of the Meissner state. Sections cover ways of engineering an optimum quasiparticle density of states and superfluid density to reduce rf losses and kinetic inductance by pairbreaking mechanisms related to magnetic impurities, rf currents, and proximity-coupled metallic layers at the surface. A section focuses on mechanisms of residual surface resistance which dominates rf losses at ultra low temperatures. Microwave losses of trapped vortices and their reduction by optimizing the concentration of impurities and pinning potential are also discussed.

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“…The value of λ is associated with the superfluid density, ρ s ∝ λ −2 , which is closely related to various fascinating phenomena including Berezinskii-Kosterlitz-Thouless transition, quantum critical point and phase fluctuations [7][8][9][10][11][12][13][14][15][16]. Currently, several useful experimental methods have been developed to achieve λ in superconducting films, such as microwave surface impedance [17][18][19][20], muon-spin relaxation (µSR) [21,22] and two-coil mutual inductance (TCMI) measurements [15,[23][24][25][26][27][28]. The microwave surface impedance measurement requires prior knowledge of its dependence on temperature to determine λ values, and it is difficult to implement continuous measurement with temperature variation using the µSR technique .…”

Section: Introductionmentioning

confidence: 99%

Calculation of penetration depth under various numerical models for the reflection-type two-coil mutual inductance technique

Liu¹,

Yao²,

Qu³

et al. 2023

Supercond. Sci. Technol.

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The two-coil mutual inductance (TCMI) technique is a useful experimental method to derive magnetic penetration depth λ in a superconducting film after proper numerical calculations, in which various film geometries including infinite, circular and quadrangle films have been utilized. Based on previously reported reflection-type TCMI experimental data taken from NbN and K-adsorbed FeSe thin films, we investigate the validity of various numerical models with different geometries by comparing their calculation results. The calculated values of λ for various film geometries become identical only when the film size is at least three times larger than the coil size. For a rectangle film with a width comparable to the coil size, the numerical models of circular and square film geometries with proper sizes can be also adopted to obtain a similar λ value as that calculated with a rectangle film geometry. Although the true value of λ can be approximately achieved only after a complicated calibration, its calculated temperature dependence is insensitive to the choice of numerical models. With these results, a proper film geometry for the numerical calculation of λ may be selected to effectively improve the calculation efficiency.

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Nonlinear Meissner effect in Nb3Sn coplanar resonators

Cited by 7 publications

References 46 publications

Depth-resolved Characterization of Meissner Screening Breakdown in Surface Treated Niobium

Depth-resolved Characterization of Meissner Screening Breakdown in Surface Treated Niobium

Tuning microwave losses in superconducting resonators

Calculation of penetration depth under various numerical models for the reflection-type two-coil mutual inductance technique

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