A5026928493- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Electronic and Structural Properties of Oxides
- ZnO doping and properties
- Magnetic properties of thin films
- Multiferroics and related materials
- Semiconductor materials and devices
- Ferroelectric and Piezoelectric Materials
- Silicon Nanostructures and Photoluminescence
- Catalytic Processes in Materials Science
- Superconductivity in MgB2 and Alloys
- Advanced Memory and Neural Computing
- Luminescence Properties of Advanced Materials
- Fluid Dynamics and Vibration Analysis
- Nanowire Synthesis and Applications
- Machine Learning in Materials Science
- Electrocatalysts for Energy Conversion
- Acoustic Wave Resonator Technologies
- Semiconductor materials and interfaces
- Copper-based nanomaterials and applications
- Thin-Film Transistor Technologies
- Copper Interconnects and Reliability
- Transition Metal Oxide Nanomaterials
- Electron and X-Ray Spectroscopy Techniques
École Polytechnique Fédérale de Lausanne
2019-2025
University of Geneva
2019-2025
Institut Català de Nanociència i Nanotecnologia
2022-2025
Institut de Ciència de Materials de Barcelona
2015-2022
University of Luxembourg
2021
Consejo Superior de Investigaciones Científicas
2016-2020
Universitat de Barcelona
2015-2016
The oxygen evolution reaction is the bottleneck to energy-efficient water-based electrolysis for production of hydrogen and other solar fuels. In proton exchange membrane water (PEMWE), precious metals have generally been necessary stable catalysis this reaction. work, we report that delamination cobalt tungstate enables high activity durability through stabilization oxide water-hydroxide networks lattice defects in acid. resulting catalysts achieve lower overpotentials, a current density...
Superconductivity in infinite-layer nickelates has stirred much research interest, to which questions regarding the nature of superconductivity remain elusive. A critical leap forward address these intricate is through growth high-crystallinity nickelates, including "parent" phase. Here, we report synthesis a high-quality thin-film nickelate, NdNiO2. This achieved perovskite precursor phase (NdNiO3) superior crystallinity on NdGaO3 substrate by off-axis RF magnetron sputtering and...
Abstract Solution deposited YBa 2 Cu 3 O 7−x (YBCO) nanocomposites with preformed nanoparticles represent a promising cost-effective approach for superior critical current properties under applied magnetic fields. Nonetheless, the majority of YBCO high nanoparticle loads (>20%) suffer from coalescence and degraded superconducting properties. Here, we study influence concentration (0–25% mol), size (5 nm–10 nm) composition (BaHfO , BaZrO ) on generation structural defects in epitaxial...
The metal-hydride-based "topochemical reduction" process has produced several thermodynamically unstable phases across various transition metal oxide series with unusual crystal structures and nontrivial ground states. Here, by such an oxygen (de-)intercalation method we synthesis a samarium nickelate ordered nickel valences associated tri-component coordination configurations. This structure, formula of Sm9Ni9O22 as revealed four-dimensional scanning transmission electron microscopy...
Most perovskite oxides belong to the Pbnm space group, composed of an anisotropic unit cell, A-site antipolar displacements, and oxygen octahedral tilts. Mapping orientation orthorhombic cell in epitaxial heterostructures that consist at least one compound is often needed for understanding controlling different degrees coupling established their coherent interfaces and, therefore, resulting physical properties. However, retrieving this information from strain maps generated with...
A methodology of general validity to prepare epitaxial nanocomposite films based on the use colloidal solutions containing different crystalline preformed oxide nanoparticles (ex situ nanocomposites) is reported. The trifluoroacetate (TFA) metal–organic chemical solution deposition route used with alcoholic solvents grow YBa2Cu3O7 (YBCO) films. For this reason stabilizing in polar a challenging goal. We have scalable nanoparticle synthetic methodologies such as thermal and microwave-assisted...
In-field angular pinning performances at different temperatures have been analysed on chemical solution deposited (CSD) YBa2Cu3O7−x (YBCO) pristine films and nanocomposites. We show that with this analysis we are able to quantify the vortex strength energies, associated kinds of natural artificial defects, acting as efficient centres regions H–T phase diagram. A good quantification variety defects active magnetic fields provides a unique tool design best landscape under operating conditions....
Superconducting nanocomposites are the best material choice to address performance required in power applications and magnets working under high magnetic fields. However, it is still challenging sort out how achieve highest superconducting using attractive competitive manufacturing processes. Colloidal solutions have been recently developed as a novel very promising low cost route manufacture nanocomposite coated conductors. Well dispersed stabilized preformance nanoparticle first prepared...
Heterostructures consisting of SmNiO3 and NdNiO3 alternating layers with additional LaAlO3 spacer were grown fully characterized by means x-ray diffraction, atomic force microscopy, scanning transmission electron microscopy. A change in the orientation orthorhombic long-axis nickelate is observed when a single unit cell inserted between NdNiO3, agreement density functional theory calculations. At same time, structure ultra-thin rhombohedral affected their proximity to layers, both microscopy...
The achievement of high critical currents in 'all-chemical' YBa2Cu3O7−δ thick films from low cost and versatile chemical solution deposition (CSD) methodology is still an open issue. Here we report a study the nucleation growth conditions to achieve excess 1 micron using single pass inkjet printing or multideposition low-fluorine metalorganic precursors. Growth layers are first investigated on LaAlO3, where there no interfacial reactivity. second architecture CSDCe0.9Zr0.1O2(CZO)/YSZ...
Enhanced pinning due to nanoscale strain is unique the high-${T}_{\mathrm{c}}$ cuprates, where pairing may be modified with lattice distortion. Therefore a comprehensive understanding of defect landscape required for broad range applications. However, determining type and distribution defects their associated constitutes critical task, this aim, real-space techniques atomic resolution characterization are necessary. Here, we use scanning transmission electron microscopy (STEM) study...
We have employed the CSD method to synthesize GdBCO and GdBCO–Gd2O3 nanocomposite 250–300 nm thin films. For this we designed a new low-fluorine solution never used before in synthesis of films that allows us reduce HF release by 80% increase reproducibility pyrolysis process. The growth these required thermal process be designed, which refer as 'flash-heating', where heating rate is extremely fast (∼600 °C min−1). structure superconducting properties pristine are excellent, showing (00 l)...
Abstract The magnetic flux pinning capabilities of YBa 2 Cu 3 O 7-x (YBCO) coated conductors vary strongly across different regions the field–temperature phase diagram and with orientation field θ . Here, we determine optimal landscape for a given region by investigating critical current density J c ( H , T ) in 5–77 K temperature range, from self-field to high fields 35 T. Our systematic analysis reveals promising routes artificially engineering YBCO any interest diagram. In...
The atomic configuration of phases and their interfaces is fundamental to materials design engineering. Here, we unveil a transition metal oxide interface, whose formation driven by energetic influences─epitaxial tensile strain versus oxygen octahedra connectivity─that compete in determining the orientation an orthorhombic perovskite film. We study this phenomenon layers LaVO3 grown on (101) DyScO3, using atomic-resolution scanning transmission electron microscopy measure intrinsic markers...
The magnetization of microwave-synthesized CoFe<sub>2</sub>O<sub>4</sub> nanoparticles, after the stringent thermal treatment that would be necessary to prepare hybrid ferromagnetic–YBCO films, is preserved.
Flash heating reduces the precursor nanoparticle coarsening and shortens growth time of epitaxial YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub> thin films.
Nanoscale mapping of the distinct electronic phases characterizing metal–insulator transition displayed by most rare-earth nickelate compounds is fundamental for discovering true nature this and possible couplings that are established at interfaces nickelate-based heterostructures. Here, we demonstrate can be accomplished using scanning transmission electron microscopy in combination with energy-loss spectroscopy. By tracking how O K Ni L edge fine structures evolve across two different...
The relationship between the formation of oxygen vacancies in apical sites YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−x</sub> structure and commonly observed Y<sub>2</sub>Ba<sub>4</sub>Cu<sub>8</sub>O<sub>16</sub> intergrowth defect has been demonstrated by examination thin-film single crystal samples.
The properties of the high-temperature superconductor $\mathrm{YB}{\mathrm{a}}_{2}\mathrm{C}{\mathrm{u}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}$ (YBCO) depend on concentration oxygen vacancies (${V}_{\mathrm{O}}$). It is generally agreed upon that ${V}_{\mathrm{O}}$ form in CuO chains, even at low concentrations where critical temperature for superconductivity peaks ($x\ensuremath{\approx}0.07$), with only a handful reports suggesting presence apical sites. In this paper, we show direct evidence...
High T c superconductor–ferromagnetic heterostructures constitute an appealing playground to study the interplay between flux vortices and magnetic moments. Here, capability of a solution‐derived route grow hybrid YBa 2 Cu 3 O 7 ‐ferromagnetic nanocomposite epitaxial thin films from preformed spinel ferrite (MFe 4 , M = Mn, Co) nanoparticles (NPs) is explored. The characterization, performed using combination structural techniques, reveals complexity resulting nanocomposites. Results show...
The effect of the oxide barrier thickness (tSiO2) reduction and Si excess ([Si]exc) increase on electrical electroluminescence (EL) properties Si-rich oxynitride (SRON)/SiO2 superlattices (SLs) is investigated. active layers metal–oxide–semiconductor devices were fabricated by alternated deposition SRON SiO2 top a substrate. precipitation thus formation nanocrystals (NCs) within was achieved after an annealing treatment at 1150 °C. A structural characterization revealed high crystalline...
An attempt to grow a thin epitaxial composite film of YBa2Cu3O7−δ (YBCO) with spinel MnFe2O4 (MFO) nanoparticles on LAO substrate using the CSD approach resulted in decomposition and various doping modes YBCO Fe Mn cations. These nanostructural effects lead lowering Tc slight Jc increase field. Using combination advanced transmission electron microscopy (TEM) techniques such as atomic resolution high-angle annular dark field scanning TEM, energy dispersive x-ray spectroscopy energy-loss we...
The shape of the electric-field-current-density (E-J) curve is determined by flux pinning and also dynamics vortices. Here, we propose a novel methodology to study normalized creep rate S in YBa