A5058142044- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- ZnO doping and properties
- Magnetic properties of thin films
- Iron-based superconductors research
- Superconductivity in MgB2 and Alloys
- Rare-earth and actinide compounds
- Superconducting Materials and Applications
- Theoretical and Computational Physics
- Nuclear Materials and Properties
- High-pressure geophysics and materials
- Ultrasonics and Acoustic Wave Propagation
- Electronic and Structural Properties of Oxides
- Nuclear Physics and Applications
- Quantum and electron transport phenomena
- Multiferroics and related materials
- Copper Interconnects and Reliability
- Characterization and Applications of Magnetic Nanoparticles
- Magneto-Optical Properties and Applications
- Semiconductor materials and devices
- HVDC Systems and Fault Protection
- Magnetic Properties of Alloys
- Acoustic Wave Resonator Technologies
- Intellectual Capital and Performance Analysis
Los Alamos National Laboratory
2014-2024
National High Magnetic Field Laboratory
2008-2024
Bariloche Atomic Centre
1997-2019
Balseiro Institute
1997-2019
The University of Tokyo
2014
Los Alamos Medical Center
2010
Comisión Nacional de Energía Atómica
1997-2005
Technische Universität Berlin
2001
We present a comparative study of the angular dependent critical current density in YBa2Cu3O7 films deposited on IBAD MgO and single crystal SrTiO3 substrates. identify three regimes where pinning is dominated by different types correlated uncorrelated defects. show that those are all cases, indicating mechanisms same, but their extension characteristics sample dependent, reflecting quantitative differences texture defect density. In particular, more defective nature turns into an advantage...
Remarkable progress has been made in the development of YBa2Cu3O7−δ (YBCO)-based coated conductors, and problems continuous processing commercially viable tape lengths are being rapidly solved by companies around world. However, current carried these tapes is presently limited to about 100A for a 1-cm-wide tape, this due rapid decrease critical density (Jc) as coating thickness increased. We have now overcome problem separating relatively thin YBCO layers with very CeO2. Using multilayer...
Abstract High critical current densities ( J c ) in thick films of the Y 1 Ba 2 Cu 3 O 7–δ (YBCO, T ≈ 92 K) superconductor directly depend upon types nanoscale defects and their within films. A major challenge for developing a viable wire technology is to introduce defect structures into YBCO grains film suitable flux pinning tailoring superconducting properties specific, application‐dependent, temperature magnetic field conditions. Concurrently, needs be integrated macroscopically...
We report significantly enhanced critical current densities (Jc) and flux pinning forces (Fp) in applied magnetic fields for YBa2Cu3O7 (YBCO) films with embedded Ba2YNbO6 (BYNO) nanorods. The were grown by pulsed laser deposition a target consisting of YBa2Cu3Oy five molar per cent additions BaNbOy Y2O3. With this composition, deposited found to contain high density BYNO nanorods that frequently traversed the entire thickness film (up 1? ?m), depending upon conditions. Enhanced Jc...
Enhanced in-field critical current densities (Jc’s) have been obtained in epitaxial superconducting (RE1,RE2)Ba2Cu3O7−x (RE1=rare-earthion 1, and RE2=rare earth ion 2) films grown on both single crystal buffered metallic substrates. For a constant average RE ionic radius (equal to that of yttrium), there is systematic dependence the Jc size variance, with small, but nonzero, variance being optimum. Compared standard YBa2Cu3O7−x composition, factor two improvement Jc(75.5K) reproducibly...
Addition of pyrochlore rare earth tantalate phases, RE3TaO7 (RTO, where RE = earth, Er, Gd and Yb) to YBa2Cu3O7−δ (YBCO) is shown vastly improve pinning, without being detrimental the superconducting transition temperature. The closely lattice matched RTO phase provides a lower interfacial energy with YBCO than BaZrO3 (BZO) produces very fine (∼5 nm) particles high linearity in their self-assembly along c. Critical current densities 0.86, 0.38 MA cm−2 at 1 3 T (for fields) parallel c axis...
We present resistivity measurements of the complete superconducting upper critical field (${H}_{c2}$) phase diagram as a function angle ($\ensuremath{\theta}$) and temperature ($T$) for cobalt-doped ${\mathrm{SrFe}}_{2}{\mathrm{As}}_{2}$ epitaxial films to 0.5 K 50 T. Although ${H}_{c2}(\ensuremath{\theta})$ at 10 is indistinguishable from that derived single-band anisotropy model, apparent ${H}_{c2}^{\ensuremath{\perp}c}/{H}_{c2}^{\ensuremath{\parallel}c}$ linearly decreases 1 low $T$, with...
We study the field (H) and temperature ($T$) dependence of critical current density (${J}_{c}$) irreversibility (${H}_{\mathrm{irr}}$) at different orientations in ${\mathrm{Y}}_{0.77}$Gd${}_{0.23}$Ba${}_{2}$Cu${}_{3}$O${}_{y}$ with randomly distributed BaZrO${}_{3}$ nanoparticles (YGdBCO$+$BZO) YBa${}_{2}$Cu${}_{3}$O${}_{y}$ (YBCO) films. Both MOD films have large RE${}_{2}$Cu${}_{2}$O${}_{5}$ (225) (\ensuremath{\sim}80 nm diameter) a high twin boundaries (TB). In addition, YGdBCO$+$BZO BZO...
The high upper critical field and low anisotropy of the iron-based superconductor BaFe2As2 make it promising for its use in construction superconducting magnets. However, current density magnetic fields needs to be improved. Here we demonstrate a simple, one-step industrially scalable means achieving just this. We show that introducing controlled amounts uniformly dispersed BaZrO3 nanoparticles into carrier-doped significantly improves performance without degrading structural or properties....
Second-generation (2G) HTS wires are now being produced routinely in kilometer lengths using Metal Organic Chemical Vapor Deposition (MOCVD) process with critical currents of 300 A/cm. While this achievement is enabling several prototype devices, order to reach a substantial commercial market, the cost-performance metrics 2G need be significantly improved device operating conditions. Zr-doping has been found an effective approach improve in-field current performance MOCVD-based wires. In...
Resonant Ultrasound Spectroscopy (RUS) is an ultrasound-based minimal-effort high-accuracy elastic modulus measurement technique. RUS as described here uses the mechanical resonances (normal modes of vibration or just modes) rectangular parallelepiped cylindrical specimens with a dimension from fraction millimeter to large will fit into apparatus. Provided all that needed so reader can construct and use state-of-the-art system. Included are links open-source circuit diagrams, download Los...
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...
Topological superconductivity is a long-sought state of matter in bulk materials, and the odd-parity superconductor UTe2 prime candidate. The recent observation field-trainable spontaneous Kerr signal at onset provides strong evidence that superconducting order parameter multicomponent breaks time-reversal symmetry. Here, we perform effect measurements on number samples—grown via both chemical vapor transport molten-salt-flux methods—that show single transition between 1.6 K 2.1 K. Our...
The angular-dependent critical current density J/sub c/ in YBa/sub 2/Cu/sub 3/O/sub 7/ films grown by pulsed laser deposition exhibit a sharp peak for magnetic field orientations near the ab plane, which arises from combined effects of intrinsic pinning and extended defects parallel to planes. An analysis temperature dependence height width this allows us distinguish both contributions. We find that, film on single crystal substrate, at low fields is due primarily defects, but high it...
The performance of Second Generation (2G) high temperature superconducting wire manufactured by continuous reel-to-reel processes is nearing the 300 A/cm-width (77 K, self field) threshold for commercial power cable applications. 2G manufacturing approach under development at American Superconductor based on combination RABiTS substrate-buffer technology with metal organic deposition (MOD) YBCO layer. capability this process has been demonstrated in multiple 10 meter lengths critical...
In this work we analyze the influence of random point defects introduced by 3 MeV proton irradiation on critical current density (${J}_{c}$) and vortex dynamics a Ba(Fe${}_{0.925}$Co${}_{0.075}$)${}_{2}$As${}_{2}$ single crystal. The results show that at low temperatures ($T$) produces an enhancement ${J}_{c}$ up to 2.6 times. However retention different magnetic fields ($H$) in elastic regime, estimated $n$ exponent vs ${(1\ensuremath{-}{(T/{T}_{c})}^{2})}^{n}$, is poorer after irradiations...
We studied the effect of systematically-controlled size (22–83 nm) and density (0.1–13 × 1021 m−3) strong pinning random BaMO3 (M=Zr, Nb, Sn) nanoparticles (NPs) by engineering their inclusion in (Y0.77Gd0.23)Ba2Cu3Oy ((Y,Gd)BCO) coated conductors. The critical current (Jc) gradually increases from that pure (Y,Gd)BCO to 3 wt% BZO with increasing NPs for H || c 45°. Moreover, at low/intermediate fields films higher densities isotropic centers show nearly angular dependence both 77 65 K,...