A5017094497- Advanced Condensed Matter Physics
- Multiferroics and related materials
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Glass properties and applications
- Physics of Superconductivity and Magnetism
- Theoretical and Computational Physics
- Material Dynamics and Properties
- Ferroelectric and Piezoelectric Materials
- Magnetic Properties and Synthesis of Ferrites
- High-pressure geophysics and materials
- Rare-earth and actinide compounds
- X-ray Diffraction in Crystallography
- Mesoporous Materials and Catalysis
- Solid-state spectroscopy and crystallography
- Crystal Structures and Properties
- Iron oxide chemistry and applications
- Nuclear Physics and Applications
- ZnO doping and properties
- Magnetic Properties of Alloys
- Metallic Glasses and Amorphous Alloys
- Magneto-Optical Properties and Applications
- Aerogels and thermal insulation
- Boron and Carbon Nanomaterials Research
- Fullerene Chemistry and Applications
Petersburg Nuclear Physics Institute
2014-2024
Kurchatov Institute
2012-2023
Peter the Great St. Petersburg Polytechnic University
2015
Physico-Technical Institute
2014
Russian Academy of Sciences
1993-2011
Bariloche Atomic Centre
2010
Consejo Nacional de Investigaciones Científicas y Técnicas
2010
Universitat Autònoma de Barcelona
2010
Universitat de Barcelona
2010
The magnetic properties of bimagnetic core/shell nanoparticles consisting an antiferromagnetic MnO core and a ferrimagnetic passivation shell have been investigated. It is found that the phase (gamma-Mn(2)O(3) or Mn(3)O(4)) depends on size nanoparticles. Structural characterizations concur while smallest predominantly gamma-Mn(2)O(3) shell, larger ones increasing amounts Mn(3)O(4). A considerable enhancement Néel temperature, T(N), anisotropy for decreasing sizes has observed. reduction also...
The intimate relationship between stoichiometry and physicochemical properties in transition-metal oxides makes them appealing as tunable materials. These features become exacerbated when dealing with nanostructures. However, due to the complexity of nanoscale materials, establishing a distinct structure-morphology functionalities is often complicated. In this regard, FexO/Fe3O4 system largely unexplained broad dispersion magnetic has been observed. Here we show, thanks comprehensive...
Inverted soft/hard, in contrast to conventional hard/soft, bi-magnetic core/shell nanoparticles of MnxFe3−xO4/FexMn3−xO4 with two different core sizes (7.5 and 11.5 nm) fixed shell thickness (∼0.6 have been synthesized. The structural characterization suggests that the particles an interface a graded composition. magnetic confirms inverted soft/hard structure evidences strong exchange coupling between shell. Moreover, larger soft exhibit smaller coercivities loop shifts, but blocking...
A study of "inverted" core-shell, MnO/gamma-Mn(2)O(3), nanoparticles is presented. Crystal and magnetic structures characteristic sizes have been determined by neutron diffraction for the antiferromagnetic core (MnO) ferrimagnetic shell (gamma-Mn(2)O(3)). Remarkably, while MnO found to a T_{N} not far from its bulk value, order gamma-Mn(2)O(3) stable above T_{C}, exhibiting two temperatures, at T approximately 40 K [T_{C}(gamma-Mn(2)O(3))] 120 [ T_{N}(MnO)]. Magnetization measurements are...
We present the results of a neutron diffraction study antiferromagnet MnO embedded in porous glass. The type magnetic ordering and structural distortion are similar to those bulk, but ordered moment 3.84(4)muB/ion is strongly reduced Néel temperature enhanced. transition second order, contrast first order bulk. size region smaller than average nanoparticles. reasons for this behavior discussed.
The ${\mathrm{N}\mathrm{a}\mathrm{N}\mathrm{O}}_{2}$ nanocomposite ferroelectric material in porous glass was studied by neutron diffraction. For the first time, details of crystal structure including positions and anisotropic thermal parameters were determined for solid material, embedded a matrix, ferro- paraelectric phases. It is demonstrated that phase consistent with bulk data, but above transition temperature giant growth amplitudes vibrations observed, resulting formation ``premelted...
Nanostructured Mn67Ga33 films exhibiting high room temperature coercivity (HC = 20.5 kOe) have been prepared by sputtering onto thermally oxidized Si substrates. Both the morphology and of can be tuned varying growth parameters. The low deposition rate film, sputtered at a reduced power working pressure, demonstrates discontinuous island-like highest HC. large HC is linked to presence anisotropy DO22 Mn3Ga phase single domain character exchange isolated, dipolar interacting, crystal islands.
Electrodeposited mesoporous CoPt alloys are demonstrated as excellent methanol oxidation catalysts in alkaline media.
Abstract Although cubic rock salt‐CoO has been extensively studied, the magnetic properties of main nanoscale CoO polymorphs (hexagonal wurtzite and zinc blende structures) are rather poorly understood. Here, a detailed neutron diffraction study on nanoparticles is presented. The blende‐CoO phase antiferromagnetic with 3rd type structure in face‐centered lattice Néel temperature T N (zinc‐blende) ≈225 K. Wurtzite‐CoO also presents an order, (wurtzite) ≈109 K, although much more complex, 2nd...
Neutron diffraction studies of antiferromagnetic MnO confined to MCM-41 type matrices with channel diameters 24--87 \AA{} demonstrate a continuous magnetic phase transition in contrast discontinuous first order the bulk. The character transforms decreasing diameter, showing critical exponent and temperature; however, latter turns out be above N\'eel temperature for This enhancement is explained within framework Landau theory, taking into consideration ternary interaction associated...
By neutron diffraction it was shown that Pb nanoparticles confined within a porous glass have an elongated form along the [111] direction which coincides with pore axis. The mean-square displacements and perpendicular to this are different. When approaching melting point displacement axis increases while in remains nearly constant as limited by walls. temperature dependence of isotropic greatly differs from bulk. softening atomic vibrations due lattice expansion confinement is negligible contrast
The controlled filling of the pores highly ordered mesoporous antiferromagnetic Co3O4 replicas with ferrimagnetic FexCo3−xO4 nanolayers is presented as a proof-of-concept toward integration nanosized units in ordered, heterostructured 3D architectures. Antiferromagnetic (AFM) mesostructures are obtained negative KIT-6 silica templates, which subsequently coated (FiM) nanolayers. tuneable magnetic properties, large exchange bias and coercivity, arising from FiM/AFM interface coupling, confirm...
This paper shows that magnetic structures result from 4$f$-3$d$ interactions induce ferroelectric polarization in the well-known green phase compound, Gd${}_{2}$BaCuO${}_{5}$ with centrosymmetric orthorhombic ($P\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}a$) crystal structure.
In the substituted ${\mathrm{Nd}}_{1\ensuremath{-}x}{\mathrm{Tb}}_{x}{\mathrm{Fe}}_{3}{({\mathrm{BO}}_{3})}_{4}$ $(x=0.1 \text{and} x=0.2)$, possessing almost easy-axis magnetic structure at low temperatures, an unusual two-step transition in fields along trigonal $c$ axis was observed by magnetization and single-crystal neutron diffraction studies. At first step, only part of Tb Ising-type moments flip to axis, which is accompanied a significant deviation antiferromagnetic Fe spins from...