Superconducting radio-frequency cavities are commonly used in modern particle accelerators for applied and fundamental research. Such cavities are typically made of high-purity, bulk Nb and with cooling by a liquid helium bath at a temperature of ∼2 K. The size, cost and complexity of operating a particle accelerator with a liquid helium refrigerator make the current cavity technology not favorable

The temperature dependences of the plasma frequency, superfluid density and London penetration depth were determined from the terahertz spectra of conductivity and the dielectric permittivity of BaFe 1.91 Ni 0.09 As 2 film with critical temperature T c = 19.6 K. Part of the experimental data were analyzed within a simple three-band Eliashberg model where the mechanism of superconducting coupling is

Novel methods are necessary to further increase the critical current density ( J c ) and uniformity of (RE)Ba 2 Cu 3 O y (RE-123; RE—rare earth element) materials. In this contribution we address several issues of infiltration growth (IG) and melt-growth (MG) processing of RE-123 bulks and show recent progress: (i) optimization of 211 composition in IG-processed mixed YGd system type for the production

We originally develop a network analysis method to study the non-ideal superconducting resonator circuits. We model the resonator device by a 3-block serial network, consisting of input feedline, resonator-coupler and output feedline. We show that the resonance curve will be modified if non-negligible discontinuity (reflection) exists at input or output side of the resonator. The extracted resonance

Precise compositional analyses at spatial resolution <1 μ m, combined with structure determination using bulk (i.e. powder XRD) and individual grain (i.e. EBSD) techniques, show that both β-Fe x Se and δ-Fe x Se form as solids in a two-phase field above and below the apparent peritectic temperature of 457 °C. Microstructures show that β-Fe x Se and δ-Fe x Se form together via exsolution when cooled

The influence of C 6 H 16 N 2 addition on the microstructural and superconducting properties of MgB 2 was systematically investigated. Unlike previously reported carbon sources, the C 6 H 16 N 2 additive had no effect on the lattice parameters of MgB 2 . However, the obvious improvement of critical current density ( J c ) was obtained for C 6 H 16 N 2 added MgB 2 without carbon substitution for boron

Submicron sized strip lines of NdFeAs(O,F) were fabricated and the transport properties were studied. By using laser lithography and dry etching, strip lines with a width as low as 0.84 μ m were fabricated. The superconducting critical temperature was not seriously affected by the fabrication process, but a significant decrease of the critical current density ( J c ) was observed for strip lines narrower

The effect of ferromagnetic buffer layer on the superconducting properties of relatively thick, high temperature superconductors is investigated. Elaborately designed heterostructure films consisting of epitaxial GdBa 2 Cu 3 O 7-x (GdBCO) on top of two types of La 0.7 Sr 0.3 MnO 3 (LSMO) layer and particles, were fabricated by pulsed laser deposition. Unlike a typical superconducting/ferromagnetic

Several new conductor designs for fusion applications, based on high temperature superconducting (HTS) materials, have been recently proposed worldwide. Most of them are based on the twisted-stacked-tape cable (TSTC) idea: a stack of HTS tapes is twisted, soldered and embedded in a copper tube, constituting what we identify here as a ‘strand’. Few strands are then twisted around a central core to make

This paper reports a diagnostic method for clarifying performance bottlenecks in superconducting wires and tapes for their further performance enhancements. In particular, our achievements by scanning Hall-probe microscopy (SHPM), which worked well for selecting positions for microstructure observation by SEM, TEM, and x-ray CT, are introduced. This hybrid microscopy offers the information of the direct

High-temperature superconducting (HTS) coated conductors (CCs) are widely regarded as a promising candidate to enable very high power density motors. These machines operate at high rotational speeds, with some designs going up to 12 000 rpm. HTS CCs are applied to the field windings of these motors to increase the magnetic loading and hence the power density. Even though the superconducting field windings

Bulk large-grain superconductors can be used as high-field permanent magnets. Although the properties of such individual trapped field magnets are well documented, much less is known concerning their behaviour when two are brought together. In this work, the interaction between two cylindrical bulk YBa 2 Cu 3 O 7 (YBCO) superconductors is described. Two sets of experiments were carried out. The first

Adiabatic superconductor logic (ASL) families are energy-efficient because they can operate with a switching energy much less than the I c Φ 0 product, where I c is the critical current for Josephson junctions, Φ 0 is the flux quantum, and I c Φ 0 is generally on the order of 10 –19 J. A switching energy of 0.03 I c Φ 0 has been demonstrated by adiabatic quantum-flux-parametron (AQFP) logic, which

Stacks of REBCO tapes can trap large amounts of magnetic fields and can stay magnetized for long periods of times. This makes them an interesting option for major engineering applications such as motors, generators and magnetic bearings. When subjected to alternating magnetic fields transverse to the magnetization (or cross fields), superconducting tapes face a reduction in the trapped field, and thus

We have developed planar nanoSQUID with nanobridge-type Josephson junctions based on the oxidation resistant and high H c 2 MoRe alloy. The objective of the research was to reduce size of the SQUID loop with the aim being to reduce magnetic flux noise and improve the spatial resolution of the SQUID sensors. Employing RF-magnetron sputtering, electron-beam lithography, and reactive ion etching in CHF

An extremely-high field nuclear magnetic resonance (NMR) spectrometer has the potential to significantly augment the resolution and sensitivity of the atomic resonance spectrum, which will significantly boost the development of a range of scientific areas. The success of an extremely-high field NMR spectrometer depends to a great extent on the development of a superconducting magnet system. A high-temperature

Quantum bits, or qubits, are an example of coherent circuits envisioned for next-generation computers and detectors. A robust superconducting qubit with a coherent lifetime of O (100 µs) is the transmon: a Josephson junction functioning as a non-linear inductor shunted with a capacitor to form an anharmonic oscillator. In a complex device with many such transmons, precise control over each qubit frequency

Proton therapy is a rapidly increasing modality to treat cancerous tumors, but large-scale implementation, and therefore widespread availability for patients, is hindered by the size and upfront investment for treatment facilities. Superconducting technology can enable more compact, and therefore more affordable treatment systems, by increasing the magnetic field in the magnets for the proton accelerator

We present the fabrication and electrical transport characterization of underdoped YBa 2 Cu 3 O 7-δ nanowires. The nanowires have been realized without any protective capping layer and they show transport properties similar to those of the parent thin film, demonstrating that they have not been damaged by the nanopatterning. The current-voltage characteristics of the underdoped nanowires show large

We demonstrate practical accelerating gradients on a superconducting radiofrequency (SRF) accelerator cavity with cryocooler conduction cooling, a cooling technique that does not involve the complexities of the conventional liquid helium bath. A design is first presented that enables conduction cooling an elliptical-cell SRF cavity. Implementing this design, a single cell 650 MHz Nb 3 Sn cavity coupled

We fabricated (Ba,Na)Fe 2 As 2 superconducting wires using the powder-in-tube method and hot isostatic pressing. By improving powder synthesis processes compared with previous studies, highly pure raw materials for the wire fabrication were obtained. The largest transport critical current density ( J c ) reached 40 kA cm −2 at T = 4.2 K under a magnetic field of 100 kOe. This value exceeds not only

We conducted electromagnetic field analyses of spiral copper-plated striated coated-conductor cable (SCSC cable), where the striated (multifilament) and copper-plated coated conductors were twisted spirally around a round core in order to decouple the filaments. We used a numerical model which was formulated with current vector potential and in which thin-strip approximation was applied to the superconductor

The results presented in this Letter describe the successful test of the first high-temperature superconducting multi-tesla insert solenoid tested at currents exceeding 4 kA while operating in a background magnetic field of a low-temperature superconducting outsert magnet. A 45-turn insert solenoid, wound from 19 meters of CORC ® cable, was designed to operate at high current, high current density

Thallium-1223, a superconductor with high critical temperature ( T c ∼ 120 K) and high irreversibility line is a promising alternative to copper layers as a low surface impedance material in particle accelerator components. In the existing design of the Future Circular Collider (FCC-hh), for reasons of cryogenic efficiency and vacuum stability, the beam screen that shields the dipoles from synchrotron

We present a comprehensive overview of a design methodology and environment that we developed to enable the implementation of microprocessors and other complex logic circuits using the adiabatic quantum-flux-parametron (AQFP) superconductor logic family. The design environment is catered for both the AIST 10 kA cm −2 Nb high-speed standard process as well as the AIST 2.5 kA cm −2 Nb standard process

The overall 30 year Nb 3 Sn conductor program for ITER provides an unusual opportunity to look at the issues created by the application of novel Nb 3 Sn technology on a large scale. ITER design criteria have evolved to make use of the features of the industrialized material, exploiting advantages as well as managing the disadvantages. There are lessons from the successes and failures to be learned

Single-crystalline samples of LuPd 2 Si 2 were studied by means of low-temperature specific heat measurements performed in a magnetic field oriented along two main crystallographic directions. The compound was found to be superconducting below 0.6 K, in agreement with previous reports. Detailed analysis of the phase-transition anomaly revealed that LuPd 2 Si 2 is a BCS-like superconductor with anisotropic

Bulk high temperature superconductors (HTS) based on the rare-earth barium cuprates [(RE)BCO] have the potential to be applied in a variety of engineering and technological applications such as trapped field magnets, rotating electrical machines, magnetic bearings and flywheel energy storage systems. The key materials figure of merit for most practical applications of bulk superconductors is simply

We report the results from a comprehensive study of the effect that annealing FeSe 0.35 Te 0.65 single crystals in different atmospheres has on the surface chemistry, the superconducting transition temperature, T c , and the critical current density, J c . A review of the literature and our data shows that annealing in oxygen, nitrogen, air or vacuum atmosphere leads to a universal superconducting

Superconductors have the unique properties of zero resistance and the Meissner effect. Lenz’s law is a fundamental law of physics. It has occasionally been questioned whether superconductors obey Lenz’s law, and there has not been an explicit answer to this question so far. Recently, we carried out experiments with superconductor coils and a magnet in search of an answer to this question. We found

Magnesium diboride (MgB 2 ) bulk superconductors may have practical applications as permanent magnets owing to their ability to trap larger fields than conventional ferromagnets and a transition temperature of 39 K that make them attractive for use in cryogen-free systems. Unlike the cuprate high temperature superconductors, grain boundaries in MgB 2 act as pinning sites not weak links, and so show

LaMnO 3− δ (LMO) films with different oxygen contents are deposited on Epi-MgO/IBAD-MgO templates using reactive magnetron sputtering under varying temperatures and atmospheres. Subsequent YBa 2 Cu 3 O 7− δ (YBCO) films are grown on LMO layers by metal-organic deposition (MOD) method. X-ray diffraction measurements reveal that YBCO texture cannot be further improved when the full width at half maximum

We present improvement in the in-field transport critical current ( I c ) of Zr-doped RE-Ba-Cu-O (REBCO, RE = rare earth) tapes to remarkable levels by post-deposition tensile-creep deformation at 580 °C. The deformed samples show up to three times higher I c than a reference sample at 77 K, 1 T when the magnetic field is parallel to the ab-plane. This enhancement in the in-field I c is attributed

The shielding (or screening current) effect in high- T c coated conductors has a strong influence on its stress/strain distribution in a coil winding, especially during high-field operations. To demonstrate this phenomenon, a special experimental setup was designed. With an LTS background magnet and a small HTS insert coil, we were able to carry out direct observations on the hoop strains of a 10 mm

The reduction of emission is a key goals for the aviation industry. One enabling technology to achieve this goal, could be the transition from conventional gas turbines to hybrid-electric drive trains. However, the requirements concerning weight and efficiency that come from applications like short range aircraft are significantly higher than what state-of-the-art technology can offer. A key technology

A novel thin film transformer based on double sided YBa 2 Cu 3 O 7−x (YBCO) thin films with high operating performance, named a high temperature superconducting thin film transformer (HTS-TFT), is proposed and tested. In this paper, we designed and fabricated four different types of HTS-TFT based on double sided YBCO thin film and measured their respective operating parameters (including winding resistance

High-temperature superconducting (HTS) maglev has great potential in the field of high-speed transportation due to its capability for passive stabilization. The levitation force between the bulk HTSs and the permanent magnet guideway is a significant parameter relating to operational safety and comfort. This force has an obvious hysteresis nonlinear characteristic, which can be represented by nonlinear

In this paper, we present new integrated on-chip planar-type superconducting quantum interference device (SQUID) first order gradiometers, which are manufactured by a new mix and match fabrication technology combining sub- μ m sized Josephson junctions (JJs) with cm-scale pickup loops. The fabrication technology is described and the design is schematically shown. These sensors have high voltage swing

Dynamic loss is significant for evaluating the performance of type-II high-temperature superconductor (HTS) coated conductors (CC), especially when used in electric machines. Although analytical expressions of dynamic loss have been proposed and verified for HTS CCs exposed to low external magnetic fields with a low current load rate, the non-linearity of dynamic loss at high current load ratios and

Conceptual designs of 1.5 and 3.0 T full-body magnetic resonance imaging (MRI) magnets using conduction cooled MgB2 superconductor are presented. The sizes, locations, and number of turns in the eight coil bundles are determined using optimization methods that minimize the amount of superconducting wire and produce magnetic fields with an inhomogeneity of less than 10 ppm over a 45 cm diameter spherical

This paper presents construction details and test results of a persistent-mode 0.5-T MgB2 magnet developed at the Francis Bitter Magnet Lab, MIT. The magnet, of 276-mm inner diameter and 290-mm outer diameter, consisted of a stack of 8 solenoidal coils with a total height of 460 mm. Each coil was wound with monofilament MgB2 wire, equipped with a persistent-current switch and terminated with a superconducting

Magnetic Resonance Imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition

Overpressure (OP) processing increases the critical current density (JC ) of Bi2Sr2CaCu2Ox (2212) round wires by shrinking the surrounding Ag matrix around the 2212 filaments, driving them close to full density and greatly increasing the 2212 grain connectivity. Indeed densification is vital for attaining the highest JC . Here, we investigate the time and temperature dependence of the wire densification

We performed a feasibility study on a high-strength Bi2-x Pb x Sr2Ca2Cu3O10-x (Bi-2223) tape conductor for high-field solenoid applications. The investigated conductor, DI-BSCCO Type HT-XX, is a pre-production version of Type HT-NX, which has recently become available from Sumitomo Electric Industries (SEI). It is based on their DI-BSCCO Type H tape, but laminated with a high-strength Ni-alloy. We

Superconducting joints are one of the key components needed to make Ag-alloy clad Bi2Sr2CaCu2O8+x (Bi-2212) superconducting round wire (RW) successful for high-field, high-homogeneity magnet applications, especially for nuclear magnetic resonance (NMR) magnets in which persistent current mode (PCM) operation is highly desired. In this study, a procedure for fabricating superconducting joints between

In this article I present our experience at the Magnet Technology Division of the MIT Francis Bitter Magnet Laboratory on liquid-helium (LHe)-free, persistent-mode MgB2 MRI magnets. Before reporting on our MgB2 magnets, I first summarize the basic work that we began in the late 1990s to develop LHe-free, high-temperature superconductor (HTS) magnets cooled in solid cryogen-I begin by discussing the

This paper presents a warm bore ferromagnetic shimming design for a high resolution NMR magnet based on spherical harmonic coefficient reduction techniques. The passive ferromagnetic shimming along with the active shimming is a critically important step to improve magnetic field homogeneity for an NMR Magnet. Here, the technique is applied to an NMR magnet already designed and built at the MIT's Francis

Long lengths of metal/MgB2 composite conductors with high critical current density (Jc), fabricated by the power-in-tube (PIT) process, have recently become commercially available. Owing to its electromagnetic performance in the 20 K - 30 K range and relatively low cost, MgB2 may be attractive for a variety of applications. One of the key issues for magnet design is stability and quench protection

We present a kinetic-inductance-based superconducting memory element with non-destructive readout, femtojoule read and write energies, both read and write shunts, which is writeable with pulses shorter than 400 ps. The element utilizes both a high-kinetic-inductance layer made from tungsten silicide as well as a low-kinetic-inductance layer made from niobium. By using tungsten silicide-which has a