Microwave Properties of a High-Temperature Superconductor and Ferromagnetic Bilayer Structure

Wu, Chien Jang; Chen, Yao‐Li

doi:10.2528/pier10111304

Cited by 9 publications

(6 citation statements)

References 23 publications

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“…In our calculations, the ScT has a T c of 92 K and 0 of 200 nm with an operating temperature of T = 4.2 K (Lin and Wu 2010). In addition to this, the impedance of the free space has a value of Z 0 = 377Ω , the free space permeability has a value of 0 = 1.256 × 10 −6 Vs∕Am Arafa 2013), the relative permittivity of the dielectric substrate has a value of r = 5.939 Ginsberg 1996), and the conductivity of the normal state has a value of n = 10 6 S∕m (Wu and Chen 2011).…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

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A Comparative study of the effective surface impedance of an HTc superconducting thin film from visible to mid-IR region

Sabra

Aly

2021

Opt Quant Electron

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In the present work, we demonstrate a comparative theoretical study for the effective surface impedance (ESI) of a HTc superconducting thin film through different electromagnetic spectrum regions such as the visible, near-infrared (NIR), and mid-infrared (MIR). Our numerical calculations are based on the impedance transformations technique (ITs) which in turn relates the ESI with the fundamental properties of HTc superconductors. In this regard, we present this study according to varying the two fundamental parameters; the operating temperature and the thickness of the superconducting thin film from the visible to MIR regions. We found that both values of the effective surface resistance R s,eff and reactance X s,eff are increased with increasing the frequency of the considered spectrum region where in visible regions the values of R s,eff and X s,eff are higher than that of the NIR and MIR regions. It is worth to mention that, the importance of this study is represented in two substantial aspects. The surface resistance demonstrates how the electromagnetic power dissipation within the superconducting thin film which in turn specifies the performance of the superconductor based devices. The surface reactance (the imaginary of the surface impedance) is proportional to the magnetic-field penetration depth which is considered an important basic property for superconductivity.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

“…Then, we can find that both R s and X s are given from the two-fluid model and the London electrodynamics as follows (Wu and Chen, 2011):…”

Section: The Proposed Design and The Basic Equationsmentioning

confidence: 99%

A Comparative study of the effective surface impedance of an HTc superconducting thin film from visible to mid-IR region

Sabra

Aly

2021

Opt Quant Electron

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“…As the conductivity of YBCO is strongly dependent on the temperature, in this part, response of the proposed fishnet metamaterial was analyzed under different temperatures. For the numerical analysis, quartz was modeled with a constant ε = 4.45 and loss of the tangent of 0.0 0 019 and the two-fluid model was used to introduce the temperature dependent conductivity of YBCO in the simu-lation [25,26] . For modeling purposes, the values of the parameters were taken from [27] .…”

Section: Quartz-ybco Combination With Varying Temperature (Thermal Tunability)mentioning

confidence: 99%

Thermally and optically tunable sub-terahertz superconducting fishnet metamaterial

Sabah

Mulla

Altan

et al. 2018

Physica C: Superconductivity and its Applications

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In this paper, a novel fishnet metamaterial structure is designed and analyzed under different material combinations and under different active controlling techniques. The results indicate that, the proposed fishnet metamaterial has a single resonance with double negativity at 0.39 THz when quartz substrate and aluminum is utilized in the design. Moreover, when the metallic parts are replaced with YBCO, the proposed design also exhibits double negativity with a stronger resonance and can be used as a switch between the double negative and single negative modes if the temperature is altered. In addition to these, when substrate (quartz) is replaced with MgO, the resonance shifts from 0.39 THz to 0.26 THz and shows double negativity. Moreover, switching properties under illumination can also be obtained when the silicon is utilized in the design (MgO-YBCO combination). According to these results, it is found that, in the case that the conductivity of silicon exceeds a certain value, the character of the resonance changes from double negative to the single negative mode.

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“…But their methods are inappropriate for the CMGs on account of the lack of ferromagnetic pole-pieces to impact the air-gap magnetic field. Recently, some researchers have calculated and investigated the characteristics of ferromagnetic material and antiferromagnetic structures according to the complex numerical methods [13,14]. Based on the Poisson's and Laplace's equation, literature [15,16] obtained a two dimension (2-D) analytical result of air-gap magnetic field for CMGs.…”

Section: Introductionmentioning

confidence: 99%

A Three Dimensional Analytical Calculation of the Air-Gap Magnetic Field and Torque of Coaxial Magnetic Gears

Ge¹,

Nie²,

Xin³

2012

PIER

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Abstract-In order to solve the defects that the end-effect of magnetic field is ignored in two dimension (2-D) analytical method or 2-D finite element method (FEM); meanwhile, mass computer resource and time for parametric design or optimization are wasted in three dimension (3-D) FEM, a concise and efficient 3-D analytical approach is put forward for the calculation of the air-gap magnetic field and torque of coaxial magnetic gears. Based on the cylindrical coordinates where a coaxial magnetic gear is in, the equivalent current model and vector magnetic potential equation of permanent magnets in high speed permanent magnetic ring are constituted. By superposed magnetic flux density of every tile permanent magnets on high speed permanent magnetic ring in cylindrical coordinates, a air-gap magnetic field 3-D analytical formula is set up without ferromagnetic pole-pieces; in the interest of modulated air-gap magnetic field 3-D analytical formula with ferromagnetic pole-pieces, three types boundary conditions using state equations of contact surfaces between ferromagnetic pole-pieces and air-gap are established by a thorough analysis of the modulate mechanism of ferromagnetic pole-pieces. Finally, magnets of the low speed permanent magnetic ring are reduced to a distribution of equivalent current, which experience the Lorentz force in modulated magnetic field of high speed permanent magnetic ring for torque calculation. The integrals in all aforementioned calculation are axial, so the end-effect is embodied in above analytical model and more precise than 2-D analytical method or 2-D FEM. As the calculation results, the formula is accurate but faster than the 3-D FEM. The analytical model is suited for programmable calculation and that will make the structural and parametric design or optimization of coaxial magnetic gears simple and timesaving.

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Microwave Properties of a High-Temperature Superconductor and Ferromagnetic Bilayer Structure

Cited by 9 publications

References 23 publications

A Comparative study of the effective surface impedance of an HTc superconducting thin film from visible to mid-IR region

A Comparative study of the effective surface impedance of an HTc superconducting thin film from visible to mid-IR region

Thermally and optically tunable sub-terahertz superconducting fishnet metamaterial

A Three Dimensional Analytical Calculation of the Air-Gap Magnetic Field and Torque of Coaxial Magnetic Gears

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