A5082591584- Physics of Superconductivity and Magnetism
- Superconductivity in MgB2 and Alloys
- Advancements in Solid Oxide Fuel Cells
- Magnetic and transport properties of perovskites and related materials
- Iron-based superconductors research
- Electronic and Structural Properties of Oxides
- Electrocatalysts for Energy Conversion
- Advanced Condensed Matter Physics
- Fuel Cells and Related Materials
- Magnesium Alloys: Properties and Applications
- Thermal Expansion and Ionic Conductivity
- Superconducting Materials and Applications
- High-pressure geophysics and materials
- Catalytic Processes in Materials Science
- Semiconductor materials and devices
- Rare-earth and actinide compounds
- Catalysis and Oxidation Reactions
- Transition Metal Oxide Nanomaterials
- Boron and Carbon Nanomaterials Research
- Machine Learning in Materials Science
- History and advancements in chemistry
- Gas Sensing Nanomaterials and Sensors
- Magnetic properties of thin films
- Conducting polymers and applications
- Acoustic Wave Resonator Technologies
Bariloche Atomic Centre
2013-2023
Consejo Nacional de Investigaciones Científicas y Técnicas
2012-2023
Balseiro Institute
2006-2023
Comisión Nacional de Energía Atómica
1994-2019
Centro Científico Tecnológico - San Juan
2019
Centro Científico Tecnológico - Tucumán
2014
Universidad Nacional de Cuyo
2012
Edison (Italy)
2010
Los Alamos National Laboratory
2001-2005
Los Alamos Medical Center
2003
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...
The critical current density (Jc) of hot isostatic pressed (HIPed) MgB2 wires, measured by d.c. transport and magnetization, is compared with that similar wires annealed at ambient pressure. HIPed have a higher Jc than the especially high temperatures magnetic fields, irreversibility field (Hirr). are promising for applications, Jc>106 A/cm2 5 K zero >104 1.5 T 26.5 K, Hirr ~ 17 4 K. improvement attributed to structural defects, which likely source vortex pinning. These observed...
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...
Abstract A thin layer of a vertically aligned nanocomposite (VAN) structure is deposited between the electrolyte, Ce 0.9 Gd 0.1 O 1.95 (CGO), and thin‐film cathode layer, La 0.5 Sr CoO 3 (LSCO), solid‐oxide fuel cell (TFSOFC). The self‐assembled VAN nanostructure contains highly ordered alternating vertical columns CGO LSCO formed through one‐step deposition process that uses pulsed laser deposition. significantly improves overall performance TFSOFC by increasing interfacial area electrolyte...
The influence of lattice strain and Mg vacancies on the superconducting properties MgB2 samples has been investigated. High quality with sharp transitions were synthesized. variation in vacancy concentrations obtained by varying synthesis conditions. It was found that high (~1%) presence (~ 5 %) resulted lowering Tc only 2 K.
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...
MgB2 samples prepared by solid-state reaction were investigated using high-resolution transmission electron microscopy (HREM), X-ray energy-dispersive spectroscopy (EDX), energy-loss (EELS), and energy-filtered imaging. Large amounts of coherent precipitates with a size range from about 5 nm up to 100 found in the crystallite matrices. The are different shapes including sphere, ellipsoid, faceted polyhedron depending on precipitates. EDX EELS analyses confirm that smaller contain magnesium,...
Transmission electron microscopy was used to probe the compositions of individual Co–Mo bimetal catalyst particles and morphologies carbon nanotubes (CNTs) catalyzed by these under flowing monoxide at 700 °C. It found that composition particle a CNT tip distribution Co within largely determine morphology CNT. A with low content (<15 at. %) tends produce long CNT, while very high (>85 onion-like structures. These observations provide insight into growth mechanisms.
This work studies the influence of microstructures and crystalline defects on superconductivity MgB2, with objective to improve its flux pinning. A MgB2 sample pellet that was hot isostatic pressed (HIPed) found have significantly increased critical current density (Jc) at higher fields than un-HIPed counterpart. The HIPed had a Jc 10 000 A/cm2 in 50 Oe (5 T) 5 K. 20 times sample, same as best reported by other research groups. Microstructures observed scanning transmission electron...
The use of MgB2 in superconducting applications still awaits the development a MgB2-based material where current-carrying performance and critical magnetic field are optimized simultaneously. We achieved this by doping with double-wall carbon nanotubes (DWCNT) as source polycrystalline samples. optimum nominal DWCNT content for increasing current density, Jc, is range 2.5–10 at.% depending on temperature. Record values upper field, Hc2(4 K) = 41.9 T (with extrapolated Hc2(0)≈44.4 T), reached...
This work describes in detail the simultaneous enhancement of upper critical field (Hc2) and current density (Jc) MgB2 bulk samples doped with nano-SiC particles, as well single-walled double-walled (dw) carbon nanotubes (CNTs). The magnetization properties were examined a superconducting quantum interference device magnetometer, four-probe transport measurements performed using 50T pulsed magnet to determine Hc2(T). We found that Jc is similar all at 5K but addition more effective improve...
The influence of rare earth (RE) ion size on critical current density (Jc) in epitaxial films superconducting REBa2Cu3O7−x was studied, where RE is the mixture two or three ions. No systematic dependence Jc found. However, strongly enhanced densities (Jc’s) were found for composition Y2∕3Sm1∕3Ba2Cu3O7−x (YSmBCO). In ∼1-μm-thick films, Jc’s as high 4.7×106Acm−2 (75.5K,0T) and 11×104Acm−2 (75.5K,5T) obtained single crystals 6×104Acm−2 buffered metal. values are up to a factor 3 higher than...
Here we describe the results of an atomic resolution study oxygen incorporation into bulk MgB2. We find that ~20-100 nm sized precipitates are formed by ordered substitution atoms onto boron lattice sites, while basic MgB2 crystal structure and orientation is preserved. The periodicity ordering dictated concentration in primarily occurs (010) plane. presence these correlates well with improved critical current density superconducting transition behavior, implying they act as pinning centers.
Thin film approach for Solid Oxide Cell (SOC) electrolytes offers a pathway to reduce the high fabrication and operation temperature of these devices. In this work, we present detailed...
We report dc transport and magnetization measurements of Jc in MgB2 wires fabricated by the powder-in-tube method, using commercial powder with 5 %at Mg added as an additional source magnesium, stainless steel sheath material. By appropriate heat treatments, we have been able to increase more than one order magnitude from that as-drawn wire. show beneficial effect annealing is elimination most micro-cracks, correlate disappearance weak-link-type behavior.
MgB 2 samples prepared by three different sets of synthesis parameters were investigated using transmission electron microscopy. Results suggest that oxygen dissolved in bulk MgB2 at high temperatures when the exposed to trace amount from flowing ultrahigh purity Ar gas. The lower solubility a temperature led precipitation nanometer-sized coherent Mg(B,O) interior grains during subsequent cooling. precipitates, which act as effective flux pinning centers, are composition-modulated structures...