Accuracy issues in surface resistance measurements of high temperature superconductors using dielectric resonators (corrected)

Mazierska, J.; Wilker, C.

doi:10.1109/77.979858

Cited by 45 publications

(19 citation statements)

References 29 publications

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“…Thus, the microwave range is the frequency regime of interest. The high sensitivity that can be achieved in microwave measurements due to the use of cylindrical resonators [38] made the rotational-symmetric current pattern a very popular choice for measurements in superconducting films [48,70]. In this case, the microwave modes TE 0xy are used (more often, 0xy = 011), and the microwave current flows along circular paths in the isotropic planes.…”

Section: Rotational Symmetric Planar Currentsmentioning

confidence: 99%

Analysis of the Measurements of Anisotropic AC Vortex Resistivity in Tilted Magnetic Fields

Pompeo

Silva

2018

IEEE Trans. Appl. Supercond.

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Measurements of the high-frequency complex resistivity in superconductors are a tool often used to obtain the vortex parameters, such as the vortex viscosity, the pinning constant and the depinning frequency. In anisotropic superconductors, the extraction of these quantities from the measurements faces new difficulties due to the tensor nature of the electromagnetic problem. The problem is specifically intricate when the magnetic field is tilted with respect to the crystallographic axes. Partial solutions exist in the free-flux-flow (no pinning) and Campbell (pinning dominated) regimes. In this paper we develop a full tensor model for the vortex motion complex resistivity, including flux-flow, pinning, and creep. We give explicit expressions for the tensors involved. We obtain that, despite the complexity of the physics, some parameters remain scalar in nature. We show that under specific circumstances the directly measured quantities do not reflect the true vortex parameters, and we give procedures to derive the true vortex parameters from measurements taken with arbitrary field orientations. Finally, we discuss the applicability of the angular scaling properties to the measured and transformed vortex parameters and we exploit these properties as a tool to unveil the existence of directional pinning. effects on other superconducting properties, is an actively pursued research [22,39,55].High frequency measurements of the electric transport properties in the mixed state provide a powerful tool to investigate the vortex motion dissipation, related to the vortex viscosity (or viscous drag), and vortex pinning, related to the Labusch parameter and the creep factor [21].When anisotropic properties are investigated, measurements are performed by tilting the applied static magnetic field H with respect to the anisotropy axes and the current direction. Then, a complicated tensor model emerges, and the analysis of the data is not straightforward.Previous works addressed separately the flux-flow regime (pinning neglected) and the pinned regime.The d.c. flux flow regime has been thoroughly investigated, so that the flux flow resistivity tensor and the related vortex viscosity tensor are well characterized [6,17,24,26,28]. In the a.c. low frequency regime, pinning is dominant. Despite the many existing theories [5,7,35], this regime has been addressed only partially [16,33,58].In [40] a full description of the complex resistivity in the low frequency, a.c. linear regime where pinning is dominant (Campbell regime) was developed. The model incorporated the material uniaxial anisotropy and point pinning in the vortex a.c. resistivity tensor with a magnetic field applied at an arbitrary orientation.In this paper we address another important issue: we develop a model for the tensor complex resistivity in the high-frequency range (typically rf and microwaves), where both dissipation (flux-flow) and pinning give comparable contributions and must be considered at the same time. We also include the effect of flux-creep, that can giv...

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Section: Rotational Symmetric Planar Currentsmentioning

confidence: 99%

Analysis of the Measurements of Anisotropic AC Vortex Resistivity in Tilted Magnetic Fields

Pompeo

Silva

2018

IEEE Trans. Appl. Supercond.

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“…It is not difficult to obtain an expression for the most probable error from (1) and relations found in [8,9]:…”

Section: Accuracy and Sensitivity Of The R S -Measurement Using A Sapmentioning

confidence: 99%

100-nm-size ferroelectric-gate field-effect transistor with 10⁸-cycle endurance

Hai

Takahashi

Zhang

et al. 2015

Jpn. J. Appl. Phys.

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We recently reported a method for measuring the microwave surface resistance (R s ) of large-area HTS films. The device was formed from a sapphire quasi-optical dielectric resonator (QDR) with conducting end-plates (CEP). In the present work, R s -measurement procedures and data obtained under different conditions are systematically analysed. The accuracy and the sensitivity of the R s -measurement are analysed. The results of the study clearly demonstrate that the proposed technique provides a sensitivity which is increased by at least one order in comparison with the most accurate cavity resonator techniques in the millimetre wave range. In addition, the first experimental results on the temperature dependence of the QDR resonances with different CEP (HTS and/or Cu) are discussed in terms of a surface reactance (X s ) measurement.

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“…If Teflon rings are cut form the same Teflon rod and the two probes are electroplated in the same condition, the loss of Teflon rings and silver in the two probes can be the same. However, the values of loss tangent of the sapphire rods are quite different even if they were cut from the same boule and polished by the same technique [11]. Thus, the loss of sapphire rods in the testing probe and calibration probe will not be the same and error occurs.…”

Section: Design Principlementioning

confidence: 98%

An Efficient and Accurate Method for HTS Surface Resistance Measurement

Cheng¹,

Chen²,

Bu³

et al. 2015

J Supercond Nov Magn

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A new way to design resonator for efficiently measuring surface resistance (R S ) of high-temperature superconductor (HTS) thin films with low uncertainty based on improved image dielectric method is developed in this paper. Simple formula is given to evaluate measurement error caused by the variation of tanδ of sapphire rod. According to the formula, this error could be decreased by choosing appropriate size of sapphire rod. Three resonators using improved image dielectric method were designed based on this new way. Interlaboratory round robin test was performed with the aim of investigating the measurement uncertainty. The round robin test shows that the relative uncertainties are no more than 12.6 % which is less than 20 % the relative uncertainty value specified in international standard on HTS thin film R S measurement. As far as the authors know, these are the most efficient devices to measure the R S of HTS thin film with equal uncertainty.

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Accuracy issues in surface resistance measurements of high temperature superconductors using dielectric resonators (corrected)

Cited by 45 publications

References 29 publications

Analysis of the Measurements of Anisotropic AC Vortex Resistivity in Tilted Magnetic Fields

Analysis of the Measurements of Anisotropic AC Vortex Resistivity in Tilted Magnetic Fields

100-nm-size ferroelectric-gate field-effect transistor with 10⁸-cycle endurance

An Efficient and Accurate Method for HTS Surface Resistance Measurement

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Accuracy issues in surface resistance measurements of high temperature superconductors using dielectric resonators (corrected)

Cited by 45 publications

References 29 publications

Analysis of the Measurements of Anisotropic AC Vortex Resistivity in Tilted Magnetic Fields

Analysis of the Measurements of Anisotropic AC Vortex Resistivity in Tilted Magnetic Fields

100-nm-size ferroelectric-gate field-effect transistor with 108-cycle endurance

An Efficient and Accurate Method for HTS Surface Resistance Measurement

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Product

Resources

About

100-nm-size ferroelectric-gate field-effect transistor with 10⁸-cycle endurance