A comprehensive study on the resistivity, magnetization and microstructure is carried out to understand the superconductivity and flux pinning behavior of hot-pressed Sr 0.6 K 0.4 Fe 2 As 2 tapes. The Sr 0.6 K 0.4 Fe 2 As 2 tapes possess excellent properties of high T c = 36.2 K, large transport J c of ∼10 5 A cm −2 at 10 T and 4.2 K, and high pinning potential U 0 / k B with small field-dependence

A first series of nitrogen infusion runs of 1.3 GHz single-cell cavities at DESY resulted in an unexpected and severe deterioration observed during the vertical cold test. To investigate the origin of the deterioration, one of the cavities underwent extensive radio-frequency measurements and a temperature- and magnetic field-mapping was performed in collaboration with the Helmholtz-Zentrum Berlin.

Quantum phase slips represent a coherent mechanism to couple flux states of a superconducting loop. Since their first direct observation, there have been substantial developments in building charge-insensitive quantum phase-slip circuits. At the heart of these devices is a weak link, often a nanowire, interrupting a superconducting loop. Owing to the very small cross-sectional area of such a nanowire

A C-band high-temperature superconducting six-channel multiplexer (sextaplexer) is proposed in this paper. A distributed coupling scheme is introduced, with which the bandpass filter (BPF) in each channel can be designed individually. The computational complexity of the proposed method is linearly increased as the number of the channels is getting larger, which is much lower than the traditional method

A detailed knowledge of the resistivity of high-temperature superconductors in the overcritical current regime is important to achieve reliable numerical simulations of applications such as superconducting fault current limiters. We have previously shown that the combination of fast pulsed current measurements and finite element analysis allows accounting for heating effects occurring during the current

A review of the theory of bi-SQUIDs and the experimental studies of bi-SQUID-based devices is presented. The reported output voltage linearity of the fabricated devices ( ##IMG## [http://ej.iop.org/images/0953-2048/33/11/113001/sustaba541ieqn1.gif] {$\sim{}$} 40 to 45 dB) is much higher than that observed for dc SQUIDs ( ##IMG## [http://ej.iop.org/images/0953-2048/33/11/113001/sustaba541ieqn2.gif]

It is significantly difficult to develop a superconducting joint between REBCO and low-temperature superconductors (LTS) using a solder matrix replacement technique. This is because the REBCO superconducting layer is highly corrosive to Sn. In this work, TEM observations were first conducted on the reaction interface between the REBCO layer and Sn to reveal the reaction. Then, a new idea to create

This work presents a generalization of the concept of current transfer length (CTL) between the stabilizer and the superconducting layer of high temperature superconductor (HTS) coated conductor tapes with a current flow diverter (CFD) architecture. The CFD architecture consists in a non-uniform interfacial resistance between the two layers, namely a high interfacial resistance in the middle of the

The Chinese Fusion Engineering Test Reactor (CFETR) is designed to build a fusion engineering Tokamak reactor generating fusion power of 200–1500 MW, and to test the breeding tritium during fusion reaction. This may require a maximum magnetic field up to 15 T in the central solenoid and toroidal field coils. New superconducting materials should be developed for satisfying the next-generation fusion

A backward computation method has been developed to accelerate modelling of the critical state magnetization current in a staggered-array bulk high-temperature superconducting (HTS) undulator. The key concept is as follows: (i) a large magnetization current is first generated on the surface of the HTS bulks after rapid field-cooling (FC) magnetization; (ii) the magnetization current then relaxes inwards

High-temperature superconductors (HTS) promise to revolutionize high-power applications like wind generators, DC power cables, particle accelerators, and fusion energy devices. A practical HTS cable must not degrade under severe mechanical, electrical, and thermal conditions; have simple, low-resistance, and manufacturable electrical joints; high thermal stability; and rapid detection of thermal runaway

The recently discovered 12442-type ACa 2 Fe 4 As 4 F 2 (A = K, Rb, Cs) compounds are the only iron-based superconductors (IBSs) with double FeAs layers between neighboring insulating layers, analogous to the double CuO 2 layers in some high- T c cuprates. Here, we report the study of vortex phase diagram of RbCa 2 Fe 4 As 4 F 2 single crystal via magneto-transport and magnetization measurements. The

Critical current density, J c , in superconductors is strongly connected with size of defects in the material. Frequently, the smaller defects, the higher J c . In this work, we tried to reduce the size of cheap commercial boron precursor powder using high energy ultra-sonication in ethanol media. The resulting powder was then utilized in synthesizing bulk MgB 2 via sintering at 775 °C. Effect of boron

The dynamic strain characteristics and responses of a low-temperature superconducting (LTS) magnet during excitation and a quench are investigated in the present work. For the strain measurements, strain gauges in the form of a half-bridge circuit comprising cryogenic strain gauges and their dummy resistances are embedded directly within the superconducting magnet structure. A wireless high-speed data

AC loss in high temperature superconducting (HTS) coils affects the performance of HTS devices. Using magnetic flux diverters (MFDs) is an effective way to reduce AC loss in HTS coils. In this paper, measurement and finite element method simulation of AC loss results in a REBCO coil assembly comprising four double pancake coils with two molypermalloy-powder MFDs are presented. Both experimental and

We present high frequency measurements of the vortex dynamics of a FeSe x Te 1 − x ( x = 0.5) thin film grown on a CaF 2 substrate and with a critical temperature T c ≃ 18 K, performed by means of a dual frequency dielectric resonator at 16.4 GHz and 26.6 GHz. We extract and discuss various important vortex parameters related to the pinning properties of the sample, such as the characteristic frequency

RE Ba 2 Cu 3 O 7-x ( RE —rare earth, Ba—barium, Cu—copper, O—oxygen) tapes used in common multilayer superconducting cables, such as Roebel cable, twisted stacked tape cable or vonductor on round core/tube (CORC ® /CORT), undergo shape modifications during the cable production. In particular, the tapes edges are regularly raised due to the Poisson effect during bending of tapes in the cable assembling

Bulk high temperature superconductors based on the rare-earth copper oxides can be used effectively as trapped field magnets capable of generating large magnetic fields. The top-seeded infiltration growth (TSIG) processing technique can provide a more homogeneous microstructure and therefore more uniform superconducting properties than samples grown using conventional melt growth processes. In the

The no-insulation (NI) winding technique greatly enhances the thermal stability of REBCO (REBa 2 Cu 3 O x , RE = Rare Earth) pancake coils by avoiding burn-out and thermal runaway. The complicated electrical behaviors in NI REBCO pancake coils produce convoluted mechanical behaviors, so that some journal papers reported that high-field NI REBCO pancake coils were mechanically damaged during quench

Self-organized nanorods in YBa 2 Cu 3 O 7−δ films are important pinning centers from the technical and fundamental views. While influence of nanoscale factors (>4–5 nm) on the vortex pinning has already been discussed in detail, the interface control of nanorods (at the smaller scale) has not yet been performed. Here, it is demonstrated that the stacking faults can control the nanorod interface to

Hydrogen-rich compounds show high- ##IMG## [http://ej.iop.org/images/0953-2048/33/11/114004/sustabb204ieqn1.gif] {$T_{\mathrm{c}}$} superconductivity related to dense hydrogen under extremely high pressure (above 100 GPa). A recent investigation to search for high- ##IMG## [http://ej.iop.org/images/0953-2048/33/11/114004/sustabb204ieqn2.gif] {$T_{\mathrm{c}}$} superconductive hydrides has advanced

We explored the superconductivity in a oxygen-hydrogen binary system, H h O 1 − h , under highpressure using an evolutionary algorithm-based materials informatics approach. We searched for metallic and superconducting phases in pressures up to 300 GPa using a crystal structure prediction technique based on a genetic algorithm and first-principles calculations, and found that hydrogen superoxide (HO

The nucleation of YBa 2 Cu 3 O 7−δ (YBCO) film deposited via metal organic decomposition (MOD) approach is a complex process that has a key role in YBCO film crystalline orientation and, consequently, superconducting properties. Up to now, several studies have been carried out to clarify this step in the fluorine based MOD route which employs only or partially metals trifluoroacetate for the precursor

Long lengths of second-generation REBCO coated conductor (CC) tapes must be joined together when power cables, coils, and magnets requiring kilometer-scale lengths are fabricated. Various resistive joining techniques of CC tapes, such as soldering and diffusion reaction, have been studied. The joint method should provide good adhesion, low joint resistance ( R j ), no critical current ( I c ) degradation

The screening current induced in rare-earth barium copper oxide (REBCO) tape generates an unwanted irregular magnetic field. The screening current-induced field (SCIF) is a challenging issue for MRI, NMR, and accelerators magnet composed of REBCO coils. A few FEM-based simulation methods have been proposed to estimate the SCIF; however, they require a long computation time. Recently, we have proposed

In this paper the roles of texturing and thickness of different buffer layers employed in the fabrication of Fe(Se,Te) coated conductors are studied. Fe(Se,Te) thin films were deposited either on rolling assisted biaxially textured substrates substrates with highly textured CeO 2 buffer layer and on HASTELLOY ® C276 substrates with a randomly oriented native oxide grown through different oxidizing

Transition-edge sensors (TESs) are thermal detectors in which a superconducting film that is electrically biased in the superconducting-to-normal transition is used as a thermometer. In most TESs, the film is a superconductor-normal metal bilayer where the two materials and their thicknesses are chosen to achieve various specifications including the transition temperature T c . Traditionally, the materials

The health monitoring of superconducting fault current limiters (SFCL) is important for their large-scale exploitation in HVDC grids protection. The intrinsic non-homogeneity of critical current along the superconductor length can cause localized points of heating, called hotspots, in the SFCL device which can lead to device damage. In this paper we propose to use an extremely simple and cost-effective

Stacks of superconducting tapes nowadays have multiple applications and many new modifications are currently considered to enhance their beneficial properties. We have studied the field trapping in stacks of commercial superconducting tapes with different configurations. Experimental and numerical analyses were performed. The superconducting stacks were magnetized to act as powerful permanent magnets

The no-insulation, or more precisely, controlled-resistance coil winding method, nowadays being exclusively used for high-temperature superconducting solenoids, has proven its effectiveness for improving quench protection. When considering low-temperature superconductor magnet technology, which is mostly focused on stability and training issues, controlled-resistance insulation windings are directly

Helium atom scattering and Auger electron spectroscopy (AES) are used to characterize the (3 × 1)-O reconstruction of the Nb(100) surface at elevated temperatures. Persistent helium diffraction peaks and specular lineshape analysis indicate that the oxide structure persists, apparently unchanged, until surface temperatures of at least 1130 K. In a complementary experiment, AES oxygen to niobium ratios

Extensive critical current density ##IMG## [http://ej.iop.org/images/0953-2048/33/10/104006/sustabaebeieqn1.gif] {${J_{\text{c}}}$} measurements are reported as a function of magnetic field ##IMG## [http://ej.iop.org/images/0953-2048/33/10/104006/sustabaebeieqn2.gif] {$B$} , temperature ##IMG## [http://ej.iop.org/images/0953-2048/33/10/104006/sustabaebeieqn3.gif] {$T$} , angle ##IMG## [http://ej.iop

Cracks caused by tensile stress in YBa 2 Cu 3 O 7-x -coated conductors (YBCO-CCs) can cause irreversible degradation to their superconducting properties. Understanding the initiation and propagation modes of cracks can assist in preventing conductor failure and enhancing their mechanical properties in further. In this study, we used a chemical etching method and scanning electron microscopy to investigate

We have investigated the low temperature isothermal current-voltage characteristics of FeSe epitaxial films with thickness of ∼ 360 nm at different magnetic fields parallel to the c axis. At zero magnetic field, with decreasing temperature a Berezinskii–Kosterlitz–Thouless transition, which often appears in two-dimensional (2D) superconductors, is observed. The current dependence of the voltage obeys

We have fabricated GdBa 2 Cu 3 O y (GdBCO) jointed coated conductors (CCs) using a method in which intermediate grown superconductive (iGS) layers of (Y,Gd)Ba 2 Cu 3 O y ((Y,Gd)BCO) are formed from an YBa 2 Cu 3 O y precursor material to investigate their growth mechanism in the superconducting joint. We characterized the nanostructural evolution of the iGS layers by in-plane x-ray diffraction, transmission

Advanced magnet systems for fusion applications would greatly benefit from the use of high-temperature superconductors (HTS). These materials allow fusion magnets to operate at higher magnetic fields, allowing for more compact fusion machines, and allow for operation at elevated temperatures, enabling demountable coils that provide access for maintenance of the fusion reactor. Quench detection remains

The high- T c superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have

In this work, we aim to demonstrate the potential of the flux flow instability (FFI) tool as a probe for the evaluation of the quasiparticle energy relaxation time τ ϵ in iron-based superconductors (IBS). The knowledge of this microscopic parameter, its temperature dependence and the magnetic field influence, turns particularly useful to implement IBS materials in photon detection applications, as

In order to enhance and/or control critical current density ( J c ) in superconducting YBa 2 Cu 3 O ##IMG## [http://ej.iop.org/images/0953-2048/33/10/105006/sustabacb0ieqn2.gif] {$_{7-\delta}$} (YBCO) thin films, different arrays of 3 µ m large ferromagnetic (iron) dots with differing configurations and shapes have been deposited on top of high-quality YBCO thin films post-buffered with a layer of

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The majority of thin film studies that were devoted to Fe-oxyarsenides has focused so far on F-substituted ( i.e. indirectly electron doped) Ln OFeAs ( Ln = La, Nd, Sm). Here we turn our attention towards Co-substituted ( i.e. directly electron doped) LaOFeAs and SmOFeAs in order to investigate its growth on different substrate materials by using pulsed laser deposition (PLD). We detected dominant

The effects of adding low-melting point metals (Pb, Sn, In and Ge) to polycrystalline CaKFe 4 As 4 (CaK1144) superconductors were investigated. We found that Sn is the most stable with CaK1144 among these low-melting point metals. Synthesis conditions as well as the doping quantity of Sn were optimized, and phase stability, microstructures and superconducting properties were investigated. At the optimized

Nanoscale pinning centers are introduced into YBa 2 Cu 3 O 7 (YBCO) films and tapes to improve vortex pinning and critical current density ( J c ) for coated conductor application. While pinning with a single type of pinning center has been mainly investigated, hybrid pinning with multiple types of pinning center is expected to be more promising for simultaneously achieving high J c values and suppressing

A compact gantry delivering 70-220 MeV protons with fixed field in the superconducting magnets could reduce the cost and improve the adoption of proton therapy. While a number of magnet and cryogenics designs have been proposed, the combined capital and operating costs of state-of-the-art superconducting materials have not been analyzed. In response, we develop a thermoeconomic model of a multi-stage

With excellent superconducting properties such as high T c , large H c2 , small anisotropy, and large J c , developments of superconducting wires and tapes of iron-based superconductors (IBSs) have been undertaken with promising results. So far, K-doped 122-type IBSs have been mainly developed for such purposes. Here, efforts to fabricate Na-doped 122-type IBS, (Ba,Na)Fe 2 As 2 , are presented. With

We present a detailed analysis of two chip-based superconducting trap architectures capable of levitating micrometer-sized superconducting particles in the Meissner state. These architectures are suitable for performing novel quantum experiments with more massive particles or for force and acceleration sensors of unprecedented sensitivity. We focus in our work on a chip-based anti-Helmholtz coil-type

Fully superconducting machines provide the high power density required for future electric aircraft propulsion. However, superconducting windings generate AC losses in AC electrical machine environments. These AC losses are difficult to eliminate at low temperatures, and they add an extra burden to the aircraft cooling system. Due to the heavy cooling penalty, AC loss in the HTS stator is one of the

REBCO coated conductors are now being used for building very high-field magnets with large electromagnetic stresses, both expected ones due to transport current ##IMG## [http://ej.iop.org/images/0953-2048/33/9/095012/sustaba79dieqn1.gif] {$\vec J$} × ##IMG## [http://ej.iop.org/images/0953-2048/33/9/095012/sustaba79dieqn2.gif] {$\vec B$} stresses and additional stresses resulting from the large screening

RE Ba 2 Cu 3 O ##IMG## [http://ej.iop.org/images/0953-2048/33/9/094014/sustaba352ieqn2.gif] {$_{7-\delta}$} coated conductors ( RE BCO-CCs; RE : rare-earth element or Y) have garnered considerable attention in high-field magnet applications. However, the twin structure existing in the ab plane of RE BCO complicates the dependence of critical current density on temperature, magnetic field, and uniaxial

Flux trapping in superconducting integrated circuits cause circuits to operate with reduced margins, or to fail completely. Moats are used in superconducting ground planes to create low energy locations for flux trapping. Moat design and placement strategies have been presented before, and several experiments published to evaluate moat efficiency. Although fluxons can be steered to moats to prevent

High-temperature superconducting (HTS) transformer windings operate subcooled at atmospheric pressure to temperatures as low as 65 K, with minimal power dissipation from AC loss in normal operation. During short circuits, HTS transformers are subjected to transient heating by currents as large as 10 times the rated current for durations of up to 2 s. After isolating the fault, HTS transformers are

Unexpected irreversible damage appeared in samples while investigating pulsed S-N switching in YBaCuO thin films. Examination of a scanning electron microscope image of a damaged film containing a defect revealed a step-like motion of the N-zone. Restoration of crack movement dynamics points to the formation of coherent jets. This would mean that cumulative convergence of unknown incompressible media

High-temperature superconducting (HTS) maglev systems show the intrinsic advantage of self-stabilizing levitation without external control, therefore, they have great potential to be a new type of rail transit. At present, the cryogenic condition (77 K) of HTS bulks is maintained by pouring liquid nitrogen (LN 2 ) into the dewar and supplementing LN 2 at regular intervals, which cannot be maintained

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We have investigated the electrical transport and magnetic properties of Eu x Ca 1 − x Fe 2 As 2 (ECFA) (0 ≤ x ≤ 1) at ambient and under high-pressure. Temperature dependence of resistance shows a distinct anomaly at T SDW ∼ 165 − 190 K due to the spin density wave (SDW) transition. Initially, T SDW increases rapidly with x up to 0.45, and then more slowly at higher x until it saturates at T SDW ∼

The first systematic study of the nano-scale periodic local density of states (LDOS) and the inhomogeneous gap distributions for the Pb doped Bi 2 Sr 2 Ca 2 Cu 3 O 10 + y (PbBi2223) microcrystals was carried out using the low-temperature scanning tunneling microscopy/spectroscopy. The spatially inhomogeneous gap distributions with patchy structures of several nm size reveal the average gap magnitude

Understanding the mechanisms that limit the current transport in granular iron-based superconductors is necessary to unlock their potential for magnet applications. This paper reports the transport critical current surface I C ( T,H ) of powder-in-tube Ag/Ba 1−x K x Fe 2 As 2 tapes densified by flat rolling and uniaxial hot pressing. We investigate the amplitude of the isothermal- I C ( H )-curve magnetic

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ReBCO superconducting cables have the potential to enable compact thermonuclear fusion reactors that operate at magnetic fields exceeding 20 T and allow operation at temperatures far exceeding the boiling point of liquid helium, potentially allowing for demountable magnets. Normal zone detection remains a challenge, and while novel quench detection techniques are an active area of research, few are

We report on the growth of NdFeAs(O,H) epitaxial thin films on MgO (001) substrates and their electrical transport properties. The maximum carrier density of the NdFeAs(O,H) films was more than twice as large as that of our NdFeAs(O,F) films. This enabled us to investigate the physical properties of heavily electron doped NdFeAsO, which could not be achieved with NdFeAs(O,F). The irreversibility field