Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be most effective dopant enhance high-field properties. However, critical role remains elusive, and also low-field current density not improved. Here, we have undertaken malic acid doping MgB2 find that microscopic origin enhancement properties due boron vacancies associated stacking faults, as observed by high-resolution...

Carbon-encapsulated crystalline boron nanopowder and coarse magnesium powder are used as inexpensive tailored starting materials for the fabrication of high-performance MgB2 superconducting wire. A low sintering temperature leads to a high critical current density, result nanometer-sized powder, surface oxidation preclusion by carbon encapsulation, grain alignment elongated powder. Detailed facts importance specialist readers published "Supporting Information". Such documents peer-reviewed,...

Abstract The urgent need for nanoporous metal oxides with highly crystallized frameworks is motivating scientists to try discover new preparation methods, because of their wide use in practical applications. Recent work has demonstrated that two‐dimensional (2D) cyanide‐bridged coordination polymers (CPs) are promising materials and appropriate this purpose ( Angew. Chem. Int. Ed. ­ 2013 , 52 1235). After calcination, 2D CPs can be transformed into a accessible surface area. Here, strategy...

We studied the effects of sintering temperature on phase transformation, lattice parameters, full width at half-maximum (FWHM), strain, critical (Tc), current density (Jc) and resistivity (ρ) in MgB2/Fe wires. All samples were fabricated by situ powder-in-tube method (PIT) sintered within a range 650–900 °C. It was observed that wires low temperature, 650 °C, resulted higher Jc up to 12 T lower Tc. The best transport value reached 4200 A cm−2 4.2 K 10 T. This is related grain boundary...

Studies of the magnetic field dependence transport critical current density (Jct) and grain connectivity MgB2/Fe wires fabricated from ball-milled boron have been conducted in detail, strong correlations found, as evidenced by differences size, transition temperature, resistivity. It was observed that samples ball milling had relatively small sizes, resulting a Jct high region. On other hand, associated with poor between adjacent grains. is clearly shown reduction low related to...

Abstract An efficient cooling system and the superconducting magnet are essential components of magnetic resonance imaging (MRI) technology. Herein, we report a solid nitrogen (SN 2 ) as valuable cryogenic feature, which is targeted for easy usability stable operation under unreliable power source conditions, in conjunction with magnesium diboride (MgB magnet. The rationally designed MgB /SN was first considered by conducting finite element analysis simulation, then demonstrator coil...

An 18-multifilamentary MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> wire, classified within the 250 m-class, was produced utilizing a technique to improve uniformity of powder filling by employing three-dimensional vibrators. A comprehensive evaluation fabricated wire revealed that critical current ( <italic xmlns:xlink="http://www.w3.org/1999/xlink">I</i> xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ) and fill factor,...

In this work, we report on significantly enhanced critical current density (Jc) in MgB2 superconductor that was easily obtained by doping with a hydrocarbon, highly active pyrene (C16H10), and using sintering temperature as low ∼600°C. The processing advantages of the C16H10 additive include production carbon (C) source, an increased level disorder, introduction small grain size, resulting enhancement Jc.

Coated conductor tapes are promising materials for the construction of high field inserts (> 20 T). In a magnet, magnetic at coil ends is not parallel to wide face tape, and angle can reach values larger than 10 degrees. conductors have very anisotropic transport properties, thus it important measure angular dependence critical current. The current commercial YBCO coated made by SuperPower has been measured 12 T, 4.2 K as function between with precision less 0.2 degree. experimental results...

Magnetic flux concentration is a very important technique for the effective generation of high magnetic fields. We propose use diamagnetism <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> bulk superconductor (HTS bulk) instead ferromagnetic materials such as Ho and Dy. fabricated field concentrator using Gd-Ba-Cu-O bulk. The essential point was slits to suppress current along...

Using high-T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> superconductors (HTS) is considered to be the only solution dramatically increase highest fields of NMR magnets because their high critical fields. However, it not easy apply HTS an spectrometer (HTS-NMR) a persistent-mode operation with cannot satisfy field stability 0.01 ppm/h at present. To overcome this problem, we are now developing HTS-NMR in driven-mode operation. As...

High-performance superconducting joints are essential for realizing persistent-mode magnets. Herein, we propose a concept and fabrication of such joints, which yielded reliable performance in the operating temperature range 4.2–25 K. MgB2–MgB2 magnets known to result deterioration localized electrical, thermal, mechanical properties. To overcome these problems, ends two wires inserted into pellet press, is then filled with mixture unreacted magnesium boron powders, followed by heat...

We report the fabrication of a magnesium diboride (MgB2) coil and evaluate its persistent-mode operation in system cooled by cryocooler with solid nitrogen (SN2) as cooling medium. The main purpose SN2 was to increase enthalpy cold mass. For this work, an situ processed carbon-doped MgB2 wire used. wound on stainless steel former single layer (22 turns), inner diameter 109 mm height 20 without any insulation. two ends were then joined make persistent-current switch obtain mode. After heat...

Abstract Superconducting joints are essential for persistent-mode operation in a superconducting magnet system to produce an ultra-stable magnetic field. Herein, we report rationally designed niobium-titanium (Nb-Ti) and their evaluation results detail. For practical applications, were fabricated by using solder matrix replacement method with two types of lead-bismuth (Pb-Bi) solder, including Pb 42 Bi 58 as new composition. All the attained critical current &gt;200 A below 1.43 T at 4.2 K....

Dual sintering induced performance variations in MgB₂superconductors are studied detail relation to MRI applications.

Abstract High magnetic fields are desirable for discovering new particles in particle accelerators. Dipole magnets using superconductors have played a key role creating the required field intensity and uniformity. In contrast, high temperature superconductor (HTS) dipole recently been spotlit because of their ability to generate higher compared low counterpart. Similar needs emerged other magnets, no-insulation (NI) technology is considered feasible option reach by overcoming disadvantages...

Because of their high critical fields, high- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> superconductors (HTS) are considered to be the only solution dramatically increase highest fields NMR magnets. We have successfully demonstrated that a 500 MHz HTS/LTS system with Bi-2223 innermost coil could used for in driven-mode operation. As next step, upgrade 920 installed at Tsukuba...

Magnetic-thermal-fluidic analyses were conducted to assess the cooling performance of magnetic nanofluids by comparing with that transformer oil and air using fully coupled finite element method (FEM) considering magnetoconvection phenomena. Magnetic (MNFs) have been studied extensively for bio- nanotechnology applications. In particular, some studies reported MNF has good characteristics thermal management electric insulation in experiments. With this motivation, study focused on MNFs...

A nuclear magnetic resonance (NMR) system using a high-temperature superconducting (HTS) magnet and probe with an HTS radio frequency coil is currently under development. The NMR expected to reduce the volume occupied by encourage users install higher field systems. RE-Ba-Cu-O-coated (REBCO-coated) conductors offer advantages of critical current density than low-temperature superconductors in fields above 10 T as well tolerance high tensile stress. Both these factors are lead reduction...

To develop powerful wind turbine generators using superconducting technology, high-performance racetrack coils are essential. Herein, we report an evaluation of a multifilamentary magnesium diboride (MgB2) conductor-based coil cooled and impregnated simultaneously by solid nitrogen (SN2). The was wound on copper former with 13 mm winding width, inner diameter 124 at the curvature, 130 length straight section. An in situ processed S-glass-insulated 36-filament MgB2 wire two layers 19.5 turns,...

The development of superconducting joining technology for reacted magnesium diboride (MgB2) conductors remains a critical challenge the advancement cryogen-free MgB2-based magnets magnetic resonance imaging (MRI). Herein, fabrication joints using carbon-doped multifilament MgB2 wires MRI is reported. To achieve successful joints, powder-in-mold method was employed, which involved tuning filament protection mechanism, powder compaction pressure, and heat treatment condition. fabricated...