A5103019160- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Crystal Structures and Properties
- Magnetic and transport properties of perovskites and related materials
- Solid-state spectroscopy and crystallography
- Organic and Molecular Conductors Research
- High-pressure geophysics and materials
- Optical and Acousto-Optic Technologies
- Superconducting Materials and Applications
- Multiferroics and related materials
- Perovskite Materials and Applications
- Photorefractive and Nonlinear Optics
- Carbon Nanotubes in Composites
- Inorganic Fluorides and Related Compounds
- Fullerene Chemistry and Applications
- Magneto-Optical Properties and Applications
- Ferroelectric and Piezoelectric Materials
- Atomic and Subatomic Physics Research
- Luminescence Properties of Advanced Materials
- Microwave Dielectric Ceramics Synthesis
- Quantum many-body systems
- Catalysis and Oxidation Reactions
- Solar and Space Plasma Dynamics
- Cavitation Phenomena in Pumps
- X-ray Diffraction in Crystallography
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine
2003-2024
National Academy of Sciences of Ukraine
1981-2024
Kuban State Agrarian University
2021-2023
Physicotechnical Institute
1989-1992
Kharkiv Institute of Physics and Technology
1981
The complete Raman spectra of a single crystal LiNiPO4 for wide temperature range are reported. Of the 36 Raman-active modes predicted by group theory, 33 have been detected. successfully analyzed in terms internal (PO4)3− and external modes. Multiphonon scattering is also discussed. Low-frequency lines, observed antiferromagnetic phase, assigned to magnon discussed briefly.
We performed Raman studies and a dielectric characterization of the pseudo-kagome Cu3Bi(SeO3)2O2X (X = Cl, Br). These compounds share competing nearest-neighbour ferromagnetic exchange frustrating next-nearest-neighbour antiferromagnetic as well highly noncollinear magnetic ground state. However, at low temperature they differ with respect to existence inversion symmetry. For both there exists pronounced interplay polar phonon modes quantum fluctuations. A novel mode appears for temperatures...
Fe$^{3+}$ $S = 5/2$ ions form saw-tooth like chains along the $a$ axis of oxo-selenite Fe$_2$O(SeO$_3$)$_2$ and an onset long-range magnetic order is observed for temperatures below $T_C 105$ K. This leads to distinct fingerprints in phonon mode linewidths energies as resolved by Raman scattering. In addition, new excitations with small emerge $T 150$ K, are assigned two-magnon scattering processes participation flat-band high energy magnon branches. From this a set exchange coupling...
A study of the IR reflectance spectra TbFe3(BO3)4 crystal. We determined frequencies polar lattice phonons in high-temperature R32, and low- temperature P3121, phases. All 8A2 ⊕ 11E-modes were found phase, with nine them corresponding to lines absorption spectrum. In low-temperature 20A2 35E-modes allowed by symmetry crystal lattice, 25E-modes found.
The IR reflectance spectra of the cubic noncentrosymmetric ferrimagnet Cu2OSeO3 (TC ≈ 60 K) were investigated in temperature range 10–80 K. Detailed analysis symmetry and composition vibrational modes was conducted on basis Raman scattering data obtained this investigation. 68 out 69 consistent with crystal lattice revealed. Some spectral features found magnetically ordered phase studied. bands at 280 421 cm−1 related to spectrum two-magnon light observed. Dynamic magnetoelectric coupling be...
We report a Raman scattering study of single-crystalline homometallic oxyborate Mn2OBO3, compound realizing one-dimensional ribbon-structure. Phonon excitations as function temperature and light polarization are compared to lattice dynamical calculations, giving evidence for strong coupling between magnetic degrees freedom. Furthermore, broader feature with distinct structure emerges at low temperatures. Based on our theoretical analysis, we assign this signal specific two-magnon processes...
Nontrivial magnetic field dependence of the polarization Kramers doublet absorption lines (15 971–15 978 cm−1) was observed in range 4I9/2 → 2H11/2 optical transition Nd3+ ion an easy-plane antiferromagnet NdFe3(BO3)4 transversal Zeeman effect geometry. Values g factor and effective exchange with Fe3+ subsystem were determined for excited state from splitting. A semiempirical equation proposed description intensities polarized components corresponding to 15 cm−1. Besides scaling factors,...
Vibrational Raman spectra of a single crystal the coupled Haldane chain compound SrNi2V2O8 with uniaxial anisotropy were investigated in 10–1000 cm−1 frequency range at temperatures 7–300 K. No structural phase transition was observed. The number phonon lines observed experiment and their intensity analyzed on basis local symmetry considerations different complexes. This approach successful explaining discrepancy between numbers expected experimentally lines. Closeness real arrangement some...
Experimental studies and group-theoretical analysis of low-temperature optical absorption spectra neodymium ferroborate crystal NdFe3(BO3)4 were carried out. It was shown that the sign exchange interaction with iron subsystem in an excited state Nd3+ can be different from ground state.
Relevance of the study. The infrastructure rural settlements has a significant impact on quality life population and, as result, development agro-industrial complex.
 Objective. purpose this study is to develop scientific and methodological provisions for improving agricultural services.
 Materials methods. research methodology includes bibliographic analysis, well analysis statistical data. To identify most factors ordinary workers, method expert assessments used.
 Results....
The optical absorption spectra of an easy-plane NdFe3(BO3)4 antiferromagnet are measured in the region 4I9/2 → 2H11/2 transition Nd3+ ion. study is performed 2–35 К temperature range, external magnetic fields up to 65 kOe directed both along С3 axis and basal plane crystal. splitting values excited states exchange field Fe3+ subsystem g-factors multiplet determined. nontrivial dependences some a indicate that these have anisotropic Fe–Nd interaction.
Electronic correlation effects in La2−xSrxNiO4 (x=1/3 and 0.225) lead to spontaneous phase separation into microscopic spin/charge stripes with commensurate incommensurate order, respectively. Raman scattering experiments on such single-crystalline materials show a rich phenomenology of phonon magnon anomalies due the new, self-organized periodicities. These are observable as function temperature but can also be induced by cooling seemingly small magnetic fields leading reorganization stripe...
The Haldane chain compound SrNi${}_{2}$V${}_{2}$O${}_{8}$ represents a topological system where magnetic degrees of freedom stem from local singlet dimer products on chain. Topological states only exist at the edges these chains, i.e. surface sample. In contrast, Raman light scattering induces different host via interchain spin exchange. These lead to non-Abelian statistics in close analogy Kitaev liquids.
Nanopowders of samarium doped magnesium aluminate phosphors have been synthesized by a co-precipitation technique. Samarium concentration was varied in the range 0.03, 0.1, 0.2, 0.3, 0.5, 1.0, 1.5 and 3 wt.%. It has found that MgAl2O4 nanopowders are amorphous state when impurities missing presence even smallest is necessary condition for formation crystalline spinel phase. Depending on synthesis temperature (Ts) content, nanoparticle size varies: from 5 nm to 6 at Ts = 700 °C 7 15 1000 °C....
Abstract Elastic moduli of LiNiPO 4 linear magnetoelectric single crystal were determined using Brillouin light scattering measurements at room temperature. The obtained values the elastic are following: c 11 = 189.6 ± 0.2, 22 192.6 0.4, 33 229.6 44 58.9 0.5, 55 70.4 0.6, 66 75.7 12 71.4 0.9, 13 71.0 0.8, and 23 54.5 0.9 in units 10 dyn/cm 2 . Determination refractive indices a He–Ne laser wavelength 632.8 nm was also carried out by means Brewster angle, following obtained: n 1.713 0.003, b...
The appearance of new phonon lines in the Raman spectrum quasi-one-dimensional antiferromagnet CsFeCl3⋅2H2O as a consequence magnetic ordering with change unit cell volume was detected experimentally. An analysis possible mechanisms that might lead to observed spectral features is done. A mechanism inducing scattering on phonons from boundary paramagnetic Brillouin zone hypothesized.