A5065633672- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Material Dynamics and Properties
- Advanced NMR Techniques and Applications
- Nuclear Physics and Applications
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Theoretical and Computational Physics
- Protein Structure and Dynamics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- NMR spectroscopy and applications
- High-pressure geophysics and materials
- Phase Equilibria and Thermodynamics
- Muon and positron interactions and applications
- Spectroscopy and Quantum Chemical Studies
- Enzyme Structure and Function
- Quantum, superfluid, helium dynamics
- Advancements in Battery Materials
- Hydrogen Storage and Materials
- Atomic and Subatomic Physics Research
- Advanced Chemical Physics Studies
- Hydrogels: synthesis, properties, applications
- Magnetic Properties of Alloys
- Multiferroics and related materials
Rutherford Appleton Laboratory
2016-2025
University of Oxford
2011-2025
ISIS Neutron and Muon Source
2024
Science and Technology Facilities Council
2008-2023
Research Complex at Harwell
2020
Didcot Community Hospital
2017
Chilton Medical Center
2016
Fondazione IRCCS Istituto Nazionale dei Tumori
2008
Heriot-Watt University
2002-2008
University of Salford
2008
Hidden Symmetry Revealed It is not often that an exact theory can describe a many-particle quantum-mechanical system, but one of the few exceptions behavior string ferromagnets—an Ising chain—at magnetic field strengths separate different types ordering. Its excitations were predicted 20 years ago to be governed by symmetry group E8, most intriguing objects in mathematics. Now, Coldea et al. (p. 177 ) report direct experimental confirmation this result quasi-one-dimensional ferromagnet CoNb...
Skyrmions are particlelike vortices of magnetization with nontrivial topology, which usually stabilized by Dzyaloshinskii-Moriya interactions (DMI) in noncentrosymmetric bulk materials. Exceptions centrosymmetric Gd- and Eu-based skyrmion-lattice (SL) hosts zero DMI, where both the SL stabilization mechanisms magnetic ground states remain controversial. We address these here investigating static dynamical spin properties host <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"...
Er_2Ti_2O_7 has been suggested to be a realization of the frustrated < 111 > XY pyrochlore lattice antiferromagnet, for which theory predicts fluctuation-induced symmetry breaking in highly degenerate ground state manifold. We present theoretical analysis classical model compared neutron scattering experiments on real material, both below and above T_N = 1.173(2) K. The correctly ordered magnetic structure, suggesting that system order stabilised by zero-point quantum fluctuations can...
The vanadium oxyfluoride [NH(4)](2)[C(7)H(14)N][V(7)O(6)F(18)] (DQVOF) is a geometrically frustrated magnetic bilayer material. structure consists of S = 1/2 kagome planes V(4+) d(1) ions with 1 V(3+) d(2) located between the layers. Muon spin relaxation measurements demonstrate absence freezing down to 40 mK despite an energy scale 60 K for antiferromagnetic exchange interactions. From magnetization and heat capacity we conclude that spins interplane are weakly coupled layers, such DQVOF...
The OSIRIS neutron instrument on the ISIS pulsed source now affords option of high-resolution quasi-elastic and inelastic spectroscopy. In this paper, performance is presented, with spectroscopic characteristics being discussed in terms energy resolution, signal to background ratio count rate. Recent improvements spectrometer are described, particular effect cooling crystal analysers close liquid helium temperature enhance sensitivity instrument. also likened back-scattering, analyser...
The superconducting state of the newly discovered superconductor ${\mathrm{K}}_{2}{\mathrm{Cr}}_{3}{\mathrm{As}}_{3}$, with a quasi-one-dimensional crystal structure $({T}_{\mathbf{c}}\ensuremath{\sim}6\text{K})$, is investigated using magnetization and muon-spin relaxation or rotation $(\ensuremath{\mu}\mathrm{SR})$ measurements. Our analysis shows that temperature dependence superfluid density obtained from transverse-field $\ensuremath{\mu}\mathrm{SR}$ measurements fits either to an...
Strong spin-orbit coupling (SOC) effects of heavy $d$-orbital elements have long been neglected in describing the ground states their compounds thereby overlooking a variety fascinating and yet unexplored magnetic electronic states, until recently. The entangled electrons such can get stabilized into unusual multiplet $J$-states which warrants severe investigations. Here we show using detailed thermodynamic studies theoretical calculations state Ba$_3$ZnIr$_2$O$_9$, 6$H$ hexagonal perovskite...
Micro- and nanoparticles are considered suitable drug delivery systems for their unique features, such as a large surface to volume ratio, the possibility tune size hydrophobicity. A polymer/polymer/water emulsion method was used producing chemically cross-linked hydrogel made of poly(vinyl alcohol) poly(methacrylate) moieties. Mesoscopic investigation microparticles accomplished by laser scanning confocal microscopy. Dynamics confined water within gel meshes studied quasi-elastic incoherent...
It has long been realized that cations play a critical role in the readsorption of water into interlayer region clay minerals. To explore possible differences dynamics related to presence clays, and examine its surface water, which plays prominent diffusion barriers comparative study was carried out highlight between montmorillonite halloysite. Whereas interact with can rehydrate after dehydration at temperature, halloysite no cations. Water is found both interlayers on these particles. In...
In order to study a diffusive behavior of Li+ in Li intercalated graphites, we have measured muon spin relaxation (μ+SR) spectra for C6Li and C12Li synthesized with an electrochemical reaction between graphite Li-ion battery. For both compounds, it was found that ions start diffuse above 230 K the obeys thermal activation process. The energy (Ea) is obtained as 270(5) meV, while Ea = 170(20) meV C12Li. Assuming jump diffusion layer C12Li, self-diffusion coefficient DLi at 310 estimated...
Extensive studies on polymer thin films to date have revealed their interesting but unusual properties such as film thickness dependence of glass transition temperature Tg and thermal expansivity. Recent shown that the lower is not always related higher mobility in films, which contradicts our current understanding process. In this work, we report results inelastic neutron-scattering measurements polystyrene using two spectrometers with different energy resolutions well ellipsometry...
In this paper, mechanisms for hydration-induced protein mobility changes at high and low temperatures are proposed.
To reveal the structure-property relationship in quasi-one-dimensional (1D) spin-chain system Ca$_3$ZnMnO$_6$, we present comprehensive results, combining basic physical characterizations such as muon spin relaxation/rotation ($\mu$SR), neutron powder diffraction (NPD), inelastic scattering (INS), and theoretical calculations. Ca$_3$ZnMnO$_6$ features a dominant intrachain coupling $J_1$ two distinct interchain interactions $J_2$ $J_3$, it undergoes antiferromagnetic ordering below...
Strong confinement of hydrogen is important for adsorption-based storage solutions, which are vital the transition toward a hydrogen-based economy. The dynamics adsorbed in high-porosity TiC-derived carbon with relatively well-stacked graphenic layers carbide-derived investigated situ inelastic and quasi-elastic neutron scattering methods. Both para-ortho rotational elastic incoherent factor investigated. Hydrogen translationally bound at temperatures 20-80 K. At 50 80 K, exhibits localized...
The present paper reports on the study of disaccharides' dynamics in aqueous solutions and discusses role their interaction with water, which seems to be responsible for protective action biological membranes tissues. In particular, using QENS (IRIS at ISIS, RAL, U.K.) we compared quasielastic spectra from three homologous disaccharides (trehalose, maltose, sucrose) a hydration 20 water molecules per each disaccharide molecule. isotopic substitution method allowed us also presence...
We report an Inelastic Neutron Scattering (INS) study of the fully deuterated molecular compound K6[V15IVAs6O42] · 9D2O (V15). Due to geometrical frustration, essential physics at low temperatures V15 cluster containing 15 coupled V4+ (S = 1/2) is determined by three weakly spin-(1/2) on a triangle. The INS spectra energy allow us directly determine effective exchange coupling J0 0.211(2) meV within triangle and gap 2Δ 0.035(2) between two doublets ground state. Results are discussed in...
Incoherent quasi-elastic neutron scattering (IQENS) and Fourier-transform infrared (FT-IR) absorption measurements have been employed to investigate the diffusional vibrational dynamics on water confined in a NaA zeolitic matrix. In analogy with results of recent experiment sol−gel silica glass (GelSil), reported preceding paper (Crupi, V.; Majolino, D.; Migliardo, P.; Venuti, V. J. Phys. Chem. B 2002, 106, 10 884), diffusive process reveals rather wide distribution relaxation times....
More than ever before, the world's increasing need for new infrastructure demands construction of efficient, sustainable and durable buildings, requiring minimal climate-changing gas-generation in their production. Maintenance-free "greener" building materials made from blended cements have advantages over ordinary Portland cements, as they are cheaper, generate less carbon dioxide more durable. The key improved performance blends (which substitute fine amorphous silicates cement) is related...
The myelin sheath is a tightly packed, multilayered membrane structure wrapped around selected nerve axons in the central and peripheral nervous system. Because of its electrical insulation axons, which allows fast, saltatory impulse conduction, crucial for proper functioning vertebrate A subset myelin-specific proteins well-defined, but their influence on dynamics, i.e. stability, has not yet been explored detail. We investigated dynamics reconstituted membranes pico- to nanosecond...
This paper reports the association between severe, prolonged, watery diarrhoea and islet cell tumours of pancreas. There appear to be significant differences patients with these symptoms those classical Zollinger-Ellison syndrome.