A5091809605- Physics of Superconductivity and Magnetism
- Superconducting Materials and Applications
- Superconductivity in MgB2 and Alloys
- HVDC Systems and Fault Protection
- Iron-based superconductors research
- Magnetic Properties and Applications
- Magnetic properties of thin films
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Theoretical and Computational Physics
- Frequency Control in Power Systems
- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- ZnO doping and properties
- Intellectual Capital and Performance Analysis
- Corporate Taxation and Avoidance
- High-pressure geophysics and materials
- Electric Motor Design and Analysis
- Rare-earth and actinide compounds
- Magnesium Alloys: Properties and Applications
- Magnetic Properties of Alloys
- Magnetic Bearings and Levitation Dynamics
- Magnetic Field Sensors Techniques
- Electronic and Structural Properties of Oxides
- Thermal Expansion and Ionic Conductivity
Kyushu Institute of Technology
2015-2024
Durham University
2023
Japan Science and Technology Agency
2013-2015
Chubu Electric Power (Japan)
2009
Kyushu University
1999-2005
Because of pressing global environmental challenges, focus has been placed on materials for efficient energy use, and this triggered the search nanostructural modification methods to improve performance. Achieving a high density tunable-sized second-phase nanoparticles while ensuring matrix remains intact is long-sought goal. In paper, we present an effective, scalable method achieve goal using metal organic deposition in perovskite system REBa2Cu3O7 (rare earth (RE)) that enhances...
Electrical connectivity and flux pinning strength of grain boundaries are essential factors in determining the critical current density superconducting polycrystalline MgB2. The effect these is quantitatively investigated for a series MgB2 bulk samples prepared by various methods. electrical evaluated using percolation model obtained used estimation residual resistivity grains. elementary force theoretical result Yetter et al based on electron scattering mechanism with resistivity. It found...
Addition of BaHfO3 (BHO) nano-rods as pinning centers into a GdBa2Cu3Oy (GdBCO) coated conductor dramatically improves the critical current properties in high magnetic fields. This is partly ascribed to strong flux these centers. In this paper it reported that improvement mainly caused by unexpected enhancement upper field, Bc2. The mechanism Bc2 not yet clear, although strain around interface between center and superconducting matrix or itself may scatter electrons. result suggests property...
BaZrO 3 doped GdBa2Cu3O7−δ superconductor was prepared by pulsed layer deposition using a KrF excimer laser, which showed isotropic characteristics of critical current density, JC, for magnetic-field orientations, ∼4.0×109 A m−2 at 1.0 T. Microstructural and morphological characterization resulting artificial pinning centers were conducted transmission electron microscopy tomography, confirmed the presence one-dimensional centers, BaZrO3 nanorods. Since there is noticeable anisotropy from...
Flux pinning properties were investigated by focusing on the origin of high peak critical current density and irreversibility field for Nd0.33Eu0.38Gd0.28Ba2Cu3Oy (NEG-123) bulk superconductors with addition 211 secondary phase particles volume fractions up to 10 mol%. It was found that a negative correlation exists between Jcp Bi various added phase. This suggests mechanisms determine are different. The do not contribute effect neither directly through condensation energy interaction nor...
The dependence of the superconducting layer thickness on critical current properties was investigated in range 0.27–2.0 µm for YBCO coated tapes made by PLD processing IBAD substrates. density at low fields direction c-axis found to decrease with increasing d proportion d−1/2 up 1 µm. This seems agree prediction two-dimensional collective pinning random point pins. However, this did not change over a wide temperature 5–60 K and be much smaller than result suggests that observed does come...
An innovative superconducting DC power cable using high-temperature wires is introduced. The new design proposed to utilize the longitudinal magnetic field effect that was discovered about a half-century ago. It shown critical current density of wire could be significantly increased when superconductor in parallel configuration. empirically known force-free structure attained for flowing this case. In cable, outer layer twisted such way shielding region generates inner conductor. As result,...
The Gargantua test station is capable of delivering a direct current 4800 A at voltage 10 V. It designed for acquiring the DC voltage-current characteristic high-temperature superconducting power cables operating 77.3 K in liquid nitrogen. goal to estimate their critical current. standardization this characterization prerequisite adoption promising technology by grid operators. This document reports on experimental setup and subsequent measurements carried out cable manufactured Sumitomo...
It was theoretically shown by the authors that current-carrying capacity of superconducting DC power cable can be enhanced choosing a force-free configuration under parallel magnetic field produced current flowing back in outer shielding conductor.This experimentally checked for single layer using Bi-2223 tapes an applied field.It found took on peak value condition total including self-field.This shows proposed structure is suitable practical transmission.The possibility innovative with...
The relationship between the condensation energy density and anisotropy parameter, γa, has been derived for Bi-2212 superconductors in various anisotropic states by analysing critical current due to columnar defects introduced heavy ion irradiation. depended on size of defects, determined kind irradiation ions. A significantly large 17.0 MA cm−2 was obtained at 5 K 0.1 T even defect a matching field 1 specimen irradiated with iodine dependence agreed well prediction from summation theory...
The authors proposed an innovative superconducting dc power cable using the longitudinal magnetic field effect, i.e., a significant enhancement of critical current density superconductor in parallel field. It was expected that with high current-carrying capacity could be realized REBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O...
The effect of the thickness Bi-2212 superconducting thin films and single crystals on critical current property is investigated in range 0.1–10 µm. peak density at low temperatures disappears for thinner than 0.5–1.0 On other hand, irreversibility field increases with increasing over entire investigation temperatures, suggesting larger 10 This behaviour different from that three-dimensional RE-123 superconductors which two thicknesses are same. While given by pinning correlation length both...
Critical current properties in Bi-2223 superconductor were investigated detail for silver-sheathed tapes fabricated by the usual process a normal pressure, previous controlled over-pressure (CT-OP) and recently improved CT-OP at final heat treatment. It was shown that critical density, irreversibility field n-value remarkably application of process. The results analysed using flux creep-flow model to seek reason improvements. found grain connectivity pinning strength recent processes,...
It was shown that the current-carrying capacity of a superconducting DC power cable could be dramatically increased using longitudinal magnetic field effect. That is, force-free structure assumed for conductor in to use significant enhancement critical current density parallel observed metallic superconductors. However, present commercial coated conductors decreases slightly with increasing field. Hence, fundamental design must changed obtain higher capacity. In spite poor field, it is still...
The critical current property of a superconducting Bi-2223 tape produced by the over pressure processing at final heat treatment was investigated. density increased factor 1.6-1.8 77.3 K in comparison with usual process. Thus, spite reduction filament thickness. It also found that irreversibility field 1.34 new As result, enhancement higher fields is remarkable. These results suggest process not only enriches mass concentration phase but contributes to c-axis alignment. This supported...
The effect of heavy ion irradiation on ISD (inclined substrate deposition)-processed DyBCO coated conductors was investigated to understand the strong flux pinning property columnar defects. It found critical current density increased at high fields parallel defects nucleated by irradiation. obtained results were analyzed using creep–flow model, and most probable value virtual in ideal creep-free case shown be due introduction This result compared with statistical summation theory it that...