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High critical temperature superconductors have zero power consumption and could be used to produce ideal electric power lines. The principal obstacle in fabricating superconducting wires and tapes is grain boundaries-the misalignment of…

A linearly polarized light normally incident on a semiconductor quantum well with spin-orbit coupling may generate pure spin current via direct interband optical transition. An electric photocurrent can be extracted from the pure spin…

Mesoscale and Nanoscale Physics · Physics 2011-04-04 Hai-Zhou Lu , Bin Zhou , Fu-Chun Zhang , Shun-Qing Shen

Iron-based superconductors have been considered to be very promising in high-field applications, for which multifilamentary wire and tape conductors with high mechanical strength are essential. In this work, 7-,19- and 114-filament…

The importance of the distribution and ``weakness'' of grain boundary junctions in the magnetic field dependence of the transport critical current in HTc films is assessed through simulations. The system is studied with the applied field…

Superconductivity · Physics 2007-05-23 R. Mulet , E. Altshuler

In layered superconductors the order parameter may be modulated within the unit cell, leading to non-trivial modifications of the vortex core if the interlayer coherence length $\xi_c(T)$ is comparable to the interlayer distance. In the…

The critical current density (Jc) through a superconductor in high magnetic fields is controlled by the inclusions and microstructure of the material that hold fluxons stationary to keep the resistance zero and is described using…

Superconductivity · Physics 2013-11-26 George J. Carty , Damian P. Hampshire

We investigate the in-field critical current density Jc(B) of SNS Josephson Junctions (JJs) and polycrystalline superconductors with grain boundaries modelled as Josephson type planar defects, both analytically and through computational…

Superconductivity · Physics 2021-10-06 A. I. Blair , D. P. Hampshire

We demonstrate the fabrication of superconducting SmFeAsO1-xFx (Sm-1111) wires by using the ex-situ powder-in-tube technique. Sm-1111 powder and a binder composed of SmF3, samarium arsenide, and iron arsenide were used to synthesize the…

Low-angle grain boundaries with misorientation angles theta < 5 degrees in optimally doped thin films of YBCO are investigated by magnetooptical imaging. By using a numerical inversion scheme of Biot-Savart's law the critical current…

Superconductivity · Physics 2009-10-31 J. Albrecht , S. Leonhardt , H. Kronmueller

In this paper, we report the synthesis, structure, transition temperature, upper critical field, critical current density and thermally activated flux flow in CaFFe0.9Co0.1As superconductor. Superconductivity arises at 23 K by Co…

Superconductivity · Physics 2012-02-27 Chandra Shekhar , Amit Srivastava , Pramod Kumar , Pankaj Srivastava , O. N. Srivastava

Hybrid superconductor-semiconductor materials are fueling research in mesoscopic physics and quantum technology. Recently demonstrated smooth $\beta$-Sn superconductor shells, due to the increased induced gap, are expanding the available…

Superconductivity · Physics 2025-02-04 B. Zhang , Z. Li , H. Wu , M. Pendharkar , C. Dempsey , J. S. Lee , S. D. Harrington , C. J. Palmstrom , S. M. Frolov

A model system consisting of a mesoscopic superconducting grain coupled by Josephson junctions to two macroscopic superconducting electrodes is studied. We focus on the effects of ohmic dissipation caused by resistive shunts and…

Superconductivity · Physics 2009-11-10 Gil Refael , Eugene Demler , Yuval Oreg , Daniel S. Fisher

From the application point of view, large critical current densities Jc (H) for superconducting wires are required, preferably for magnetic fields higher than 5 T. Here we show that strong c-axis textured Sr1-xKxFe2As2 tapes with nearly…

We theoretically investigate an opportunity to implement a source of highly spin-polarized ac current on the basis of superconductor/weak ferromagnet/superconductor (SFS) voltage-biased junction in the regime of essential proximity effect…

Superconductivity · Physics 2011-10-18 A. M. Bobkov , I. V. Bobkova

We have investigated the transport and noise properties of submicron YBCO bicrystal grain-boundary junctions prepared using electron beam lithography. The junctions show an increased conductance for low voltages reminiscent of Josephson…

Superconductivity · Physics 2009-10-31 F. Herbstritt , T. Kemen , L. Alff , A. Marx , R. Gross

Magneto-fluctuations of the normal resistance RN have been reproducibly observed in YBa2Cu3O7-d biepitaxial grain boundary junctions at low temperatures. We attribute them to mesoscopic transport in narrow channels across the grain boundary…

The most effective way to enhance the dissipation-free supercurrent in presence of magnetic field for type II superconductors is the introduction of defects that acts as artificial pinning centres (APCs) for the vortices. For instance, the…

Critical current density Jc in polycrystalline or granular superconducting material is known to be hysteretic with applied field H due to the focusing of field within the boundary between adjacent grains. This is of concern in the so-called…

Superconductivity · Physics 2009-11-13 A. A. Gapud , D. K. Christen , R. Feenstra , F. A. List , A. Khan

By applying a highly sensitive homemade AC susceptibility technique to Pr_{x}Y_{1-x}Ba_2Cu_3O_7 polycrystals (with x=0.0, 0.1 and 0.3), we observed very sharp Fraunhofer type low-field periodic oscillations of the real part of the AC…

Monofilamentary MgB2-wires with a 2- or 3-component sheath containing mechanical reinforcing stainless steel (SS) were prepared and characterized. In direct contact to the superconductor Nb, Ta or Fe was used. For a selection of samples…

Superconductivity · Physics 2015-06-24 R. Nast , S. I. Schlachter , S. Zimmer , H. Reiner , W. Goldacker