Reduction of ac transport and magnetization loss of a high-Tc superconducting tape by placing soft ferromagnetic materials at the edges

Gömöry, Fedor; Šouc, J; Vojenčiak, M; Alamgir, A.K.M.; Han, Z.; Gu, Chen

doi:10.1063/1.2710753

Cited by 17 publications

(13 citation statements)

References 14 publications

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“…In this case the elliptical equivalent of the multifilamentary zone for critical state model can offer good conformity with experiment [2], [3] in spite of the disagreement revealed by the scanning of magnetic field.…”

Section: Discussionsupporting

confidence: 54%

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Magnetic Field Mapping Above the Superconducting Tape With Ni-Covered Edges

Solovyov

Vojenčiak

Gömöry

2009

IEEE Trans. Appl. Supercond.

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Covering the edges of a Bi-2223/Ag tape conductor by a layer of soft ferromagnetic material has positive impact on its two basic performance characteristics in low magnetic fields: the critical current is improved by 20%, and both the magnetization and transport AC loss are reduced. Reasonable theoretical prediction of the critical current in the tape is obtained by a numerical finite-element method: the whole superconducting portion is saturated by the critical current density assumed to be anisotropic and dependent on the magnetic field. However, for the prediction of AC loss the intermediate states with partial saturation of superconductor are also significant. We studied experimentally the development of magnetic field above a common multifilamentary Bi-2223/Ag tape with edges covered by nickel during stepwise change of the transport DC current. Indirect information about the distribution of electrical current and hence the process of magnetic flux penetration and dissipation at changing the value of current can be extracted from these experiments.

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Section: Discussionsupporting

confidence: 54%

“…It leads to the 20% increase of the Critical Current in weak magnetic fields (less than 50 mT) [2], [3]. Also, increasing Manuscript allows to reduce the losses in AC regime, even with the account of hysteretic losses in ferromagnetic part.…”

Section: Introductionmentioning

confidence: 98%

Magnetic Field Mapping Above the Superconducting Tape With Ni-Covered Edges

Solovyov

Vojenčiak

Gömöry

2009

IEEE Trans. Appl. Supercond.

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“…The main idea of these works is to use the ferromagnetic sheath to shield magnetically the whole superconductor or the part of it from the applied magnetic field and/or from the self-induced field. It was experimentally proved that this method could lead to improve the critical current at finite magnetic fields in MgB 2 /Fe wires [4] and BSCCO film covered by Ni [9] and to enhance the critical current in hybrid Nb/Co structure in the parallel magnetic field [6] as well as in Al film placed close to the Co/Pt stripe in a perpendicular magnetic field [7] and to decrease ac losses in BSCCO superconductors partially covered by Ni [11].…”

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confidence: 99%

“…The last decade has seen a large activity (see for example [1,2,3,4,5,6,7,8,9,10,11]) in studying the superconductor-ferromagnetic systems in which the magnetic field of the magnet can be used for enhancing the critical current of the superconductor at zero and finite magnetic fields. The main idea of these works is to use the ferromagnetic sheath to shield magnetically the whole superconductor or the part of it from the applied magnetic field and/or from the self-induced field.…”

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confidence: 99%

Strong influence of a magnetic layer on the critical current of Nb bridge in finite magnetic fields due to surface barrier effect

Vodolazov

Gribkov

Klimov

et al. 2009

Applied Physics Letters

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We measured the critical current of the bilayer Nb/Co in the applied magnetic field. When the magnetic field was tilted to the axis which was perpendicular to the plane of the bilayer we observed a large difference in critical currents flowing in opposite directions. We found that the largest critical current of the bilayer exceeded the critical current of the superconductor without Co layer in a wide range of the tilted magnetic fields. The theory which takes into account the surface barrier effect for vortex entry and magnetic field of the magnetic layer gave a quantitative explanation of our experimental results. PACS numbers: Keywords:The last decade has seen a large activity (see for example [1,2,3,4,5,6,7,8,9,10,11]) in studying the superconductor-ferromagnetic systems in which the magnetic field of the magnet can be used for enhancing the critical current of the superconductor at zero and finite magnetic fields. The main idea of these works is to use the ferromagnetic sheath to shield magnetically the whole superconductor or the part of it from the applied magnetic field and/or from the self-induced field. It was experimentally proved that this method could lead to improve the critical current at finite magnetic fields in MgB 2 /Fe wires [4] and BSCCO film covered by Ni [9] and to enhance the critical current in hybrid Nb/Co structure in the parallel magnetic field [6] as well as in Al film placed close to the Co/Pt stripe in a perpendicular magnetic field [7] and to decrease ac losses in BSCCO superconductors partially covered by Ni [11].This work studies the dependence of the critical current (I c ) of the Nb/Co bilayer on the direction and value of the applied magnetic field and compares it with I c of the superconducting bridge with a removed ferromagnetic layer. We prove that in our sample both bulk pinning and a strong surface barrier for vortex entrance exist. We demonstrate that in such superconductors the magnetic layer has much stronger influence on its transport properties than in superconductors with only bulk pinning [4,8,9]. The effect is mainly connected with a strong dependence of the width of the vortex free region (which exists in superconductors with a surface barrier [12,13,14]) on the local magnetic field. We observe a big difference in the value of the critical current depending on the direction of the current flow and we demonstrate that the largest critical current of a bilayer is larger than the critical current of the superconductor without magnetic layer in a wide range of the magnetic fields.The samples were fabricated in one process from Nb/Si/Co multilayer by Ar etching process in photoresist mask. The Nb bridge was fabricated by a reactive magnetron spattering and it had the critical temperature about 9.2 K. Ferromagnetic Co layer and Si layer as dielectric interlayer were prepared by magnetron spattering. The thicknesses of Nb, Si and Co layers were about 100 nm and the width and the length of the fabricated bridge were 2 and 6 µm, respectively. The magnetic state of the Co...

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“…10,11 Furthermore, there are a series of works including experiments and numerical simulations in studying the effects of ferromagnetic substrates on ac losses. [12][13][14][15][16][17][18][19][20] Recently, a theoretical investigation of ac transport and magnetization loss in a SC/FM thin strip has been reported. 21,22 The 2G HTS tapes should have not only the desired electrical properties but also the mechanical properties that ensure the structural integrity through all the processes from coil winding to operation.…”

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confidence: 99%

Influence of soft ferromagnetic substrate on magneto-elastic behavior in a superconducting coated conductor strip

Xue

Yong

et al. 2013

Journal of Applied Physics

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A new magneto-elastic resonance based technique to determine magneto-mechanical parameters of amorphous ferromagnetic ribbons Rev. Sci. Instrum. 84, 043904 (2013); 10.1063/1.4799177Magneto-elastic behaviour of thin type-II superconducting strip with field-dependent critical current Ferromagnetic materials will affect not only the electromagnetic response but also the mechanical behaviors of coated conductors. The influence of soft ferromagnetic substrate on magneto-elastic behavior in a superconductor/ferromagnetic (SC/FM) bilayer exposed to a transverse magnetic field is investigated theoretically. The ferromagnetic substrate is regarded as ideal soft magnets with high permeability and small magnetic hysteresis. Due to the composite structure of SC/FM hybrids, magneto-elastic behavior will be subjected to combined effect of equivalent force and flexural moment. Analytical expressions for internal stress and strain components are derived by virtue of a two-dimensional elasticity analysis. It is worth pointing out that the y component of strain has much larger positive value during field ascent, which may result in the delamitation at the interface. Irreversible magnetostrictive behaviors are observed both along x direction and along y direction. For the thickness dependence of magnetostriction, the flexural moment dominates when the SC thickness is small while the equivalent force plays a critical role at higher SC thickness. V C 2013 AIP Publishing LLC. [http://dx.

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Reduction of ac transport and magnetization loss of a high-Tc superconducting tape by placing soft ferromagnetic materials at the edges

Cited by 17 publications

References 14 publications

Magnetic Field Mapping Above the Superconducting Tape With Ni-Covered Edges

Magnetic Field Mapping Above the Superconducting Tape With Ni-Covered Edges

Strong influence of a magnetic layer on the critical current of Nb bridge in finite magnetic fields due to surface barrier effect

Influence of soft ferromagnetic substrate on magneto-elastic behavior in a superconducting coated conductor strip

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