A5005160945- NMR spectroscopy and applications
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Advanced NMR Techniques and Applications
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Rare-earth and actinide compounds
- Iron oxide chemistry and applications
- Magnetism in coordination complexes
- Quantum, superfluid, helium dynamics
- Lanthanide and Transition Metal Complexes
- Physics of Superconductivity and Magnetism
- Advanced MRI Techniques and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Atomic and Subatomic Physics Research
- Nanopore and Nanochannel Transport Studies
- Superconductivity in MgB2 and Alloys
- Topological Materials and Phenomena
- Graphene research and applications
- Nanoparticle-Based Drug Delivery
- 2D Materials and Applications
- Hydrocarbon exploration and reservoir analysis
- Metal-Organic Frameworks: Synthesis and Applications
- Clay minerals and soil interactions
- Theoretical and Computational Physics
National Centre of Scientific Research "Demokritos"
2014-2024
Khalifa University of Science and Technology
2022
Vanderbilt University
2018
Technological Educational Institute of Athens
2009
National Institute for Research and Development of Isotopic and Molecular Technologies
2008
Universitat de València
2006
Instituto de Ciencia de Materiales de Sevilla
2006
Royal Holloway University of London
1987-1997
55Mn NMR line shape measurements in La1-xCaxMnO3 for 0.20< or =x< =0.50 provide experimental evidence about the existence of two distinct regions T-x magnetic phase diagram, where homogeneous ferromagnetic (FM) metallic state is separated into FM and insulating regions. These results are agreement with recent theoretical predictions, which reveal a novel electronic separation states, providing orbital ordering Jahn-Teller phonons taken consideration.
${T}_{1}$ measurements have been performed on the solid phase of helium-3 adsorbed Grafoil. A theory has developed to interpret these data basis hypothesis a single correlation time for exchange-induced spin motion. We infer that relaxation is mediated by internuclear dipolar interaction. show how ${T}_{1}$-minima together with exact moment and hydrodynamic calculations may be used approximate spectral functions over their whole range. Thus we obtain numerical values exchange frequency all...
Sulfur copolymers with high sulfur content find a broad range of applications from Li–S batteries to catalytic processes, self-healing materials, and the synthesis nanoparticles. Synthesis sulfur-containing polymers via inverse vulcanization technique gained lot attention due feasibility reaction produce (up 90 wt %). However, interplay between cross-linker structure has not yet been fully explored. In present work, effect amount 1,3-diisopropenyl benzene (DIB) on structural stability...
One of the most significant challenges implementing colloidal magnetic nanoparticles in medicine is efficient heating microliter quantities by applying a low frequency alternating field. The ultimate goal to accomplish nonsurgically treatment millimeter size tumors. Here, we demonstrate synthesis, characterization, and vitro as well vivo efficiency dextran coated maghemite (γ-Fe2O3) ferrofluid with an exceptional response heating. difference previous synthetic attempts high charge coating,...
Titanium dioxide (TiO2) is an excellent photocatalytic material that imparts biocidal, self-cleaning and smog-abating functionalities when added to cement-based materials. The presence of TiO2 influences the hydration process cement development its internal structure. In this article, a pore network pastes containing different ratios were studied using two noninvasive techniques (ultrasonic NMR). Ultrasonic results show addition enhances mechanical properties paste during early-age...
Abstract Structural and morphological control of crystalline nanoparticles is crucial in the field heterogeneous catalysis development “reaction specific” catalysts. To achieve this, colloidal chemistry methods are combined with ab initio calculations order to define reaction parameters, which drive chemical reactions desired crystal nucleation growth path. Key this procedure experimental verification predicted facets their corresponding electronic structure, case nanostructured materials...
The use of salicylaldehyde oxime (H2salox) in iron(III) carboxylate chemistry has yielded two new hexanuclear compounds [Fe6(μ3-O)2(O2CPh)10(salox)2(L)2]·xMeCN·yH2O [L = MeCONH2, x 6, y 0 (1); L H2O, 2, 3 (2)]. Compound 1 crystallizes the triclinic space group P1̄ with (at 25 °C) a 13.210(8) Å, b 13.87(1) c 17.04(1) α 105.79(2)°, β 96.72(2)°, γ 116.69(2)°, V 2578.17(2) Å3, and Z 1. 2 monoclinic C2/c 21.81(1) 17.93(1) 27.72(1) 111.70(2)°, 10070(10) 4. Complexes contain [Fe6(μ3-O)2(μ2-OR)2]12+...
We report on the deposition of thin nanolayers MoS2 material carbon nanofibers (CNFs) and multiwalled nanotubes (CNTs) by in situ thermal decomposition (NH4)2MoS4 oleylamine. The synthesized MoS2@CNF MoS2@CNT nanocomposites were characterized X-ray diffraction (XRD), transmission electron microscopy (TEM), energy loss spectroscopy (EELS), Raman spectroscopy. TEM results indicate that CNFs, as well CNTs, provide an excellent template for growth nanolayers. 2–5 layers thick nanocrystals 5–10...
Water, when confined at the nanoscale acquires extraordinary transport properties, and yet, there is no direct experimental evidence of these properties resolution. Here, by using two-dimensional NMR diffusion–relaxation (D–T2) spin–lattice – spin–spin relaxation (T1–T2) spectroscopy, we succeeded to resolve water diffusion in single- double-walled carbon nanotubes (SWCNTs/DWCNTs). In SWCNTs, spectra display characteristic shape uniform restricted one dimension. Remarkably, DWCNTs, shown...
55Mn and 139La NMR measurements on a high quality single crystal of ferromagnetic (FM) La0.80Ca0.20MnO3 demonstrate the formation localized Mn(3+,4+) states below 70 K, accompanied by strong cooling-rate dependent increase certain FM neutron Bragg peaks. (55,139)(1/T(1)) spin-lattice (139)(1/T(2)) spin-spin relaxation rates are strongly enhanced approaching this temperature from below, signaling genuine phase transition at T(tr) approximately K. The disappearance metallic signal applying...
Abstract The synthesis, crystal structures, spectroscopic and magnetic properties studies of four trinuclear oxo‐centered carboxylate complexes are reported discussed: [Cr 3 (μ ‐O){O 2 C(OH)Ph } 6 (H O) ](NO ) · 2H O 3Me CO ( 1· CO), ‐O)(O CPh) 1.9MeCN 0.5H 2· O), [Fe 5.69H 3· 3MeCN 4· 3MeCN). From a crystallographic point view, the three metal ions form an isosceles triangle in 1 (benzilato complexes) almost equilateral one 4 (benzoato complexes). Magnetic susceptibility measurements reveal...
Novel polymer gel electrolytes have been prepared by incorporating LiI-I(2) solutions into a polyethylene oxide matrix supported TiO(2) filler. The electrolytes, based on either acetonitrile or propylene carbonate solvents are compared with liquid standard ones and examined (7)Li solid state nuclear magnetic resonance relaxometry diffusion measurements. In parallel, the triiodide apparent coefficient has determined linear sweep voltammetry. results correlated atomic force microscopic images...
The structural and magnetic properties spin dynamics of dextran coated uncoated γ-Fe(2)O(3) (maghemite) nanoparticles have been investigated using high resolution transmission electron microscopy (HRTEM), (57)Fe nuclear resonance (NMR), Mössbauer spectroscopy dc magnetization measurements. HRTEM observations indicated a well-crystallized system ellipsoid-shaped nanoparticles, with an average size 10 nm. combined study suggested the existence significant interparticle interactions not only in...
Low-temperature ${}^{139}\mathrm{La}$ and ${}^{55}\mathrm{Mn}$ NMR line shape measurements in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ for $0.125<~x<~0.5,$ ${\mathrm{La}}_{0.67}({\mathrm{Ca}}_{1\ensuremath{-}y}{\mathrm{Ba}}_{y}{)}_{0.33}{\mathrm{MnO}}_{3}$ $0<~y<~1$ are shown to directly reflect changes of the structure magnetic state at a local level. For low x values evidence is given about presence polaronic lattice distortions. By increasing x,...
Abstract Detecting the metallic Dirac electronic states on surface of Topological Insulators (TIs) is critical for study important quantum properties (SQPs), such as Majorana zero modes, where simultaneous probing bulk and edge electron required. However, there a particular shortage experimental methods, showing at atomic resolution how electrons extend interact with interior nanoscaled TI systems. Herein, by applying advanced broadband solid-state 125 Te nuclear magnetic resonance (NMR)...
The influence of coating on interparticle interactions in ferrofluids has been investigated using various techniques such as Mössbauer spectroscopy, magnetometry, transmission electron microscopy, photon correlation X-ray diffraction, photoelectron, and resonance micro-Raman spectroscopy. Aging spin-glass-like behavior was frozen concentrations from dense, initial value 40 mg coated nanoparticles per 1 mL water, to dilute 1:10 (4 mg/mL). as-prepared nanoparticles, core size 7−8 nm, were...
A nanosized HY zeolite was synthesized and studied by means of 1H 27Al NMR during thermal dehydration in the temperature range 20–600 °C. The nanozeolite is comprised a mixture well-crystallized ultrathin platelets octahedral nanocrystals, dressed with pentacoordinated extraframework Al(V). spin–lattice (T1) spin–spin (T2) relaxation measurements combination 3Q-MAS reveal two different interaction paths between water molecules solid matrix: (i) strongly interacting Al(V) cations, indicated...
We report (139)La nuclear magnetic resonance in ferromagnetic and insulating (FMI) La(1-x)Ca(x)MnO(3), 0.10< or =x< =0.20, which at low temperatures shows the formation of Mn octants with enhanced Mn-O wave function overlapping electron-spin alignment. The rapid increase relaxation rates "wipeout" NMR signal intensity on heating, imply a quasistatic character for octant cells FMI phase, freeze below transition temperature T(f).
Highly mesoporous SiO2-encapsulated NixPy crystals, where (x, y) = (5, 4), (2, 1), and (12, 5), were successfully synthesized by adopting a thermolytic method using oleylamine (OAm), trioctylphosphine (TOP), oxide (TOPO). The Ni5P4@SiO2 system shows the highest reported activity for selective hydrogenation of SO2 toward H2S at 320 °C (96% conversion 99% selectivity to H2S), which was superior commercial CoMoS@Al2O3 catalyst (64% 71% °C). morphology Ni5P4 crystal finely tuned via adjustment...