A5091513311- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Electronic and Structural Properties of Oxides
- Multiferroics and related materials
- Magnetic properties of thin films
- Theoretical and Computational Physics
- ZnO doping and properties
- Characterization and Applications of Magnetic Nanoparticles
- Rare-earth and actinide compounds
- Iron oxide chemistry and applications
- Magnetic Properties of Alloys
- Ferroelectric and Piezoelectric Materials
- Advanced Memory and Neural Computing
- Copper-based nanomaterials and applications
- Physics of Superconductivity and Magnetism
- Nanoparticle-Based Drug Delivery
- Quantum and electron transport phenomena
- Advanced Battery Materials and Technologies
- Environmental remediation with nanomaterials
- Magnetic Properties and Applications
- Magnetic Properties and Synthesis of Ferrites
- Nanomaterials for catalytic reactions
- Advancements in Battery Materials
- Metallic Glasses and Amorphous Alloys
- Adsorption and biosorption for pollutant removal
Institut de Ciència de Materials de Barcelona
2016-2025
Universitat Autònoma de Barcelona
2012-2024
Consejo Superior de Investigaciones Científicas
2006-2022
Institut de Microelectrònica de Barcelona
2018
Lawrence Berkeley National Laboratory
2007
Imperial College London
1998-2006
Centro Nacional de Microelectrónica
2006
Universitat Politècnica de Catalunya
2003
Polish Academy of Sciences
2001
Institute of Physics
2001
$\ensuremath{\gamma}\ensuremath{-}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ magnetic nanoparticles, with a very high surface to volume ratio, exhibit both strong exchange anisotropy and training effect. At the same time field irreversibility in $M\left(H\right)$ curves zero cooled--field cooled (ZFC-FC) processes has also been detected. A low temperature spin-glass-like transition is evidenced at ${T}_{F}\ensuremath{\approx}42\mathrm{K}$ even...
The role of the synthesis conditions on cationic Fe/Mo ordering in Sr2FeMoO6 double perovskite is addressed. It shown that this can be controlled and varied systematically. has a profound impact saturation magnetization material. Using appropriate protocol record value 3.7muB/f.u. been obtained. Mossbauer analysis reveals existence two distinguishable Fe sites agreement with P4/mmm symmetry charge density at Fe(m+) ions significantly larger than (+3) suggesting contribution to spin-down...
In the present work, we analyze geometry and composition of nanostructures obtained from oxidation iron nanoparticles. The initial takes place by outward diffusion cations through growing oxide shell. This net material flow is balanced an opposite vacancies, which coalesce at metal/oxide interface. Thus, partial colloidal nanoparticles leads to formation core−void−shell nanostructures. Furthermore, complete in 3−8 nm size range hollow We temperature vacancy coalescence during...
Abstract Lithium‐sulfur batteries (LSBs) are still limited by the shuttle of lithium polysulfides (LiPS) and slow Li−S reaction. Herein, we demonstrate that when using cobalt sulfide as a catalytic additive, an external magnetic field generated permanent magnet can significantly improve LiPS adsorption ability reaction kinetics. More specifically, results show both experimentally theoretically how electron spin polarization Co ions reduces repulsion enhances degree orbital hybridization,...
Abstract The catalytic activation of the Li‐S reaction is fundamental to maximize capacity and stability batteries (LSBs). Current research on catalysts mainly focuses optimizing energy levels promote adsorption conversion, while frequently overlooking electronic spin state influence charge transfer orbital interactions. Here, hollow NiS 2 /NiSe heterostructures encapsulated in a nitrogen‐doped carbon matrix (NiS @NC) are synthesized used as additive sulfur cathodes. heterostructure promotes...
An AB2X4 spinel structure, with tetrahedral A and octahedral B sites, is a paradigmatic class of catalysts several possible geometric configurations numerous applications, including polysulfide conversion in metal–sulfur batteries. Nonetheless, the influence configuration composition on mechanisms catalysis precise manner which facilitate polysulfides remain unknown. To enable controlled exposure single active configurations, herein, Cotd2+ Cooh3+ Co3O4 for sodium are large part replaced by...
Beyond optimizing electronic energy levels, the modulation of spin configuration is an effective strategy, often overlooked, to boost activity and selectivity in a range catalytic reactions, including oxygen evolution reaction (OER). This frequently accomplished using external magnetic fields, which makes it impractical for real applications. Herein, achieved by engineering Ni/MnFe
Heteroatom-doping has emerged as a transformative approach to producing high-performance catalysts, yet the current trial-and-error optimize these materials remains ineffective. To enable rational design of more efficient models grounded in deeper understanding catalytic mechanisms are essential. Existing models, such d-band center theory, fall short explaining role dopants, particularly when dopants do not directly interact with reactants. In this study, we synthesize various...
Cold-pressed powders of the half-metallic ferromagnet ${\mathrm{CrO}}_{2}$ are dielectric granular metals. Hysteretic magnetoresistance with maxima at coercive field arises from interparticle contacts. Dilution insulating antiferromagnetic ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ powder reduces conductivity by 3 orders magnitude, but enhances ratio which reaches 50% 5K. The negative is due to tunneling between contiguous ferromagnetic particles along a critical path spin-dependent Coulomb gap.
The magnetoresistance behavior of Fe3O4 in polycrystalline thin film, powder compact, and single-crystal form are compared. Negative with peaks at the coercive field, observed films compacts but not single crystal, is due to field-induced alignment magnetization contiguous grains. effect associated intergranular transport spin-polarized electrons.
The low-field (LFMR) and high field (HFMR) magnetoresistance response of ceramic ${\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3}$ (LSMO) samples having grain sizes diameters \ensuremath{\emptyset} ranging from 10 \ensuremath{\mu}m to 20 nm have been investigated. A limiting LFMR about \ensuremath{\approx}30% is obtained for the \ensuremath{\approx}0.5 but no larger values are by further reduction size down nanometric range. On contrary, HFMR progressively rises when reducing size....
Electron doping in the ferromagnetic and metallic double perovskites ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$ is achieved via partial substitution of ${\mathrm{Sr}}^{2+}$ by ${\mathrm{La}}^{3+}.$ We show that this promotes an extraordinary rising Curie temperature about 70 K above pristine compound. This finding reveals coupling mediated itinerant carriers, thus providing solid experimental support to double-exchange picture for magnetic interactions. The observation ${T}_{C}$ can be...
The magnetoresistance of La2/3Sr1/3MnO3/CeO2 composites is explored as a function the metal/insulator composition, temperature, and magnetic field. An important enhancement low-field observed for samples close to metallic percolation threshold. improved field sensitivity still fairly large at room temperature. Manganese perovskites may constitute new alternative development magnetoresistive devices.
55Mn nuclear magnetic resonance experiments are reported on a series of fully strained epitaxial La(2/3)Ca(1/3)MnO3 thin films SrTiO3. We have found evidence multiple phase segregation into ferromagnetic metallic and nonmetallic regions as well that nonferromagnetic insulating. These insulating mainly located close to interfaces may significant impact the performance spin-tunnel devices. As result segregation, coupling within is depressed. This accounts for reduction Curie temperature...
The enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR; EC 1.1.1.34) catalyzes the first rate-limiting step in plant isoprenoid biosynthesis. Arabidopsis thaliana contains two genes, HMG1 and HMG2, that encode HMGR. We have cloned these genes analyzed their structure expression. HMG2 consist of four exons three small introns interrupt coding sequence at equivalent positions. share similarity regions but not 5'- or 3'-flanking regions. mRNA is detected all tissues, whereas presence...
We show both experimental evidences and Monte Carlo modeling of the effects interparticle dipolar interactions on hysteresis losses. Results indicate that an increase in intensity produce a decrease magnetic susceptibility losses, thus diminishing hyperthermia output. These findings may have important clinical implications for cancer treatment.
Abstract The Fe‐MgO core‐shell morphology is proposed within the single‐domain nanoparticle regime as an enhanced magnetically driven hyperthermia carrier. combinatory use of metallic iron a core material together with increased particle size (37–65 nm) triggers tuning dipolar interactions between particles and allows for further enhancement their collective heating efficiency via concentration control. A theoretical universal estimation hysteresis losses reveals role on outlines strong...
The use of magnetic nanoparticles (MNPs) to locally increase the temperature at nanoscale under remote application alternating fields (magnetic particle hyperthermia, MHT) has become an important subject nanomedicine multidisciplinary research, focusing among other topics on optimization heating performance MNPs and their assemblies effect field. We report experimental data heat released by using a wide range anisometric shapes in different media. outline basic theoretical investigation,...
The electrochemical oxygen evolution reaction (OER) plays a fundamental role in several energy technologies, which performance and cost-effectiveness are large part related to the used OER electrocatalyst. Herein, we detail synthesis of cobalt-iron oxide nanosheets containing controlled amounts well-anchored SO42- anionic groups (CoFexOy-SO4). We use cobalt-based zeolitic imidazolate framework (ZIF-67) as structural template cobalt source Mohr's salt ((NH4)2Fe(SO4)2·6H2O) iron sulfate. When...
Catalytic additives able to accelerate the lithium–sulfur redox reaction are a key component of sulfur cathodes in batteries (LSBs). Their design focuses on optimizing charge distribution within energy spectra, which involves refinement and occupancy electronic density states. Herein, beyond distribution, we explore role spin configuration polysulfide adsorption properties catalytic activity additive. We showcase importance this parameter by generating polarization through defect engineering...
We have studied the thickness dependence of magnetotransport properties ${\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ thin films epitaxially grown on ${\mathrm{SrTiO}}_{3},$ ${\mathrm{LaAlO}}_{3},$ and ${\mathrm{NdGaO}}_{3}$ single-crystalline substrates. When decreases, a global disruption magnetoelectronic occurs, namely resistivity low-temperature magnetoresistance increase while metal-to-insulator transition temperature ${(T}_{\mathrm{P}})$ is lowered. state that electronic...
In this work we carefully analyze the role of microstructure on magnetic properties Co-doped ZnO nanoparticles prepared by vaporization-condensation method in a solar reactor. We show that close correlation exists between microstructural features and appearance ferromagnetism. Both shape size particles, as well microstructure, can be controlled changing pressure inside evaporation chamber, evidenced transmission electron microscopy micrographs high resolution (HREM). X-ray diffraction...
Although most of the experimental work dealing with magnetic relaxation systems characterized by existence an energy-barrier distribution have been analyzed in terms so-called logarithmic approximation, this is not a good approximation because obviously it cannot describe behavior for whole range temperatures and times. An alternative method called ln(t/${\mathrm{\ensuremath{\tau}}}_{0}$) scaling proposed. This allows one to extrapolate at times that are experimentally completely...