A5081106194- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Magnetic properties of thin films
- High-pressure geophysics and materials
- Semiconductor materials and interfaces
- Crystal Structures and Properties
- Rare-earth and actinide compounds
- Quantum and electron transport phenomena
- Surface and Thin Film Phenomena
- Magneto-Optical Properties and Applications
- X-ray Diffraction in Crystallography
- Multiferroics and related materials
- Theoretical and Computational Physics
- Magnetic Properties and Applications
- Copper-based nanomaterials and applications
- ZnO doping and properties
- Magnetic Properties and Synthesis of Ferrites
- Advanced Chemical Physics Studies
- Superconductivity in MgB2 and Alloys
- Superconducting Materials and Applications
- Inorganic Fluorides and Related Compounds
- Iron oxide chemistry and applications
- Magnetism in coordination complexes
- Thermal Expansion and Ionic Conductivity
Krasnoyarsk Scientific Center
2015-2025
Institute of Physics
2015-2025
Siberian Federal University
2016-2025
Russian Academy of Sciences
2013-2023
Lomonosov Moscow State University
2023
Maxwell Institute for Mathematical Sciences
2023
University of Edinburgh
2023
Institute of Engineering Physics
2013-2023
Czech Academy of Sciences, Institute of Physics
2000-2023
San Francisco State University
2011-2020
Complex cobalt oxides known as cobaltites are reviewed, including LnCoO3-based perovskite-structured rare-earth (where Ln is lanthanum or a lanthanide), quasi-two-dimensional and quasi-one-dimensional of the types LnCo2O5+?, La2CoO4, Ca3Co2O8, NaxCoO2 ? yH2O superconducting compounds. Key experimental theoretical results presented, with emphasis on interplay between charge, spin, orbital degrees freedom. Two problems specific relevance to spin state instability Co3+ ions in LnCoO3, nature...
Fe K-edge x-ray magnetic circular dichroism of magnetite (Fe3O4) powders was measured with synchrotron radiation under variable pressure and temperature conditions in diamond anvil cell. The observed to decrease discontinuously by approximately 50% between 12 16 GPa, independent temperature. transition is attributed a high-spin intermediate-spin Fe2+ ions the octahedral sites could account for previously structural electrical anomalies at this range. interpretation data supported emission...
The microscopic origin of ultrafast modification the ratio between symmetric ($J$) and antisymmetric ($D$) exchange interaction in antiferromagnetic iron oxides is revealed, using femtosecond laser excitation as a pump terahertz emission spectroscopy probe. By tuning photon energy pulse we show that effect light on $D/J$ two archetypical ${\mathrm{FeBO}}_{3}$ ${\mathrm{ErFeO}}_{3}$ maximized when resonance with spin parity forbidden $d\ensuremath{-}d$ transition crystal-field split states...
A hybrid scheme for the electronic structure calculations of strongly correlated electron systems is proposed. The ab initio local density approximation calculation used to construct Wannier functions and obtain single Coulomb parameters multiband Hubbard-type model. In strong correlation regime within Hubbard model calculated by generalized tight-binding method, which combines exact diagonalization Hamiltonian a small cluster (unit cell) with perturbation treatment intercluster hopping...
A different ``Hubbard energy control'' mechanism of the insulator-metal transition (IMT) in Mott-Hubbard insulators is discussed. This can be initiated by lattice compression and it driven a spin crossover $3{d}^{5}$ ions from high-spin state to low-spin state. The suppresses effective Hubbard parameter ${U}_{\text{eff}}$ down value enabling according Mott ${U}_{\text{eff}}/W\ensuremath{\approx}1$. classification possible scenarios metallization other $3{d}^{n}$ metal compounds also performed.
Electronic spectra of 3d(n) transition ions in an octahedral ligand surrounding have been studied using the modified crystal field approach (MCFA), which includes a relativistic spin-orbital interaction. A new variable parameter, effective nuclear charge Z(eff) metal ion that allows accounting implicitly covalence degree metal-ligand bond, has introduced. Energy diagrams similar to Tanabe-Sugano ones calculated. To study spin state evolution arbitrary distorted complex, diagram proposed. The...
Many microscopic models with interaction between the next-nearest neighbours as a key parameter to cuprate physics inspired us study here diagonal superexchange in CuO$_2$ layer. Our investigation shows extended hopping give correct representation of magnetic interactions only hypothetical square layer, where neighbors always has AFM nature. The conclusions are based on presence symmetry prohibition FM contribution total for simple but not real We actually confirm also there justified...
It is known that in a weak magnetic field ($H < 1$~kOe) at $T T_C \approx 87$~K, rare-earth cobalt oxide LaCoO$_3$ has ferromagnetic properties. The physical mechanism of the...
The dependence of the energies and orbital structure local states in CuO monolayer on intra- interatomic Coulomb interactions copper oxygen orbitals is studied. electronic system described within eight-band p-d model hole representation with on-site hopping integrals obtained using density functional theory. cluster multiparticle eigenstates are calculated exact diagonalization. difference between energy dependencies parameters for predominant probability d-orbital which occupies p-orbitals...
Magnetic and M\"ossbauer spectroscopy (MS) measurements have been performed on a single crystal of Co${}_{2.25}$Fe${}_{0.75}$O${}_{2}$BO${}_{3}$ with ludwigite structure. Two magnetic transitions (${T}_{N}=115 $K ${T}_{C}=70 $K) were traced from the ac susceptibility temperature dependence. The MS spectra as function clearly show onset ordering below 115 K. Magnetization parent Co${}_{3}$O${}_{2}$BO${}_{3}$ Fe${}_{3}$O${}_{2}$BO${}_{3}$ compounds done for comparison. In anisotropy different...
Pronounced magnetic-field- and bias-sensitive features of the transport properties a Fe/SiO2/p-Si hybrid structure in planar geometry at temperature variation are investigated. Comparative analysis two samples, one with continuous Fe film other electrodes formed from layer separated by micron gap, shows that these due to metal-insulator-semiconductor (MIS) transition Schottky barrier near interface between SiO2 p-Si. Resistance such MIS depends exponentially on bias. In ferromagnetic film,...
We have investigated the x-ray diffraction (XRD) structure, magnetic susceptibility, and heat capacity of GdCoO${}_{3}$ in a wide temperature range. A model phase separation low-spin (LS) high-spin (HS) states has been proposed based on analysis XRD peak shape anomalies range 200--800 K. From measurements we separated HS Co${}^{3+}$ contribution fitted it with temperature-dependent spin gap. found smooth LS-HS crossover at $T=800$ The possible intermediate (IS) state to thermodynamics is...