33 results on '"Egorysheva, A."'
Search Results
2. Highly frustrated Bi-Cr-Sb-O pyrochlore with spin-glass transition
- Author
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Roman Svetogorov, O.M. Gajtko, O.G. Ellert, A. V. Egorysheva, and D. I. Kirdyankin
- Subjects
Materials science ,Spin glass ,Rietveld refinement ,Pyrochlore ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,XANES ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Ion ,Crystallography ,Oxidation state ,Phase (matter) ,engineering ,Antiferromagnetism ,0210 nano-technology - Abstract
The detailed study of magnetic properties, including dc and ac measurements, has been carried out on the Bi-Cr-Sb-O pyrochlore. The region of pyrochlore phase existence was determined and photocatalytic properties have been also studied. We revealed that the Bi-Cr-Sb-O pyrochlore phase occurs along Bi2−xCr1+xSbO7 section within the region x = 0.1–0.4. The Cr3+ ions oxidation state in Bi-Cr-Sb-O pyrochlore was confirmed by XANES spectra. The best Rietveld refinement results for Bi1.8Cr1.2SbO7 composition were achieved for the disordered structure model (space group Fd-3m). According to the magnetic data Bi1.8Cr1.2SbO7 is a highly frustrated pyrochlore with short-range antiferromagnetic exchange interactions between the nearest Cr3+ ions. At Tg = 4 К this compound undergoes spin-glass transition.
- Published
- 2018
3. Comparative study of luminescent properties of Bi1-xPrxGeSbO6 and La1-xPrxGa0.5Sb1·5O6 (x = 0–0.5) solid solutions with rosiaite structures
- Author
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I.A. Yurlov, S. A. Khrushchalina, S.V. Golodukhina, Polina A. Ryabochkina, A. D. Taratynova, and A. V. Egorysheva
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Materials science ,Praseodymium ,Phonon ,Biophysics ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Ion ,Bismuth ,chemistry ,Activator (phosphor) ,Particle size ,0210 nano-technology ,Luminescence ,Solid solution - Abstract
In this work, Bi1-xPrxGeSbO6 (x = 0–0.5) solid solutions were synthesized, and the corresponding properties were compared to those of La1-xPrxGa0.5Sb1·5O6. The lattice parameters of the La1-xPrxGa0.5Sb1·5O6 solid solutions decrease linearly as the activator concentration increases. This linear reduction is only observed for the a parameter for Bi1-xPrxGeSbO6. Parameter c shows non-linear growth, which is related to the structural features of BiGeSbO6. Increasing the activator content leads to a decrease in the particle size, which is 0.5–8 μm for Bi1-xPrxGeSbO6. The influence of the host composition on the spectral-luminescent properties of the solid solutions was determined. The difference in the phonon frequencies of BiGeSbO6 and LaGa0.5Sb1·5O6 leads to different luminescence quenching processes for Pr3+ ions. Interactions between Pr3+ ions and Bi3+ were observed for Bi1-xPrxGeSbO6 solid solutions. These processes give rise to changes in the ratios of the luminescence bands of these ions. All the bismuth-containing solid solutions are characterized by the appearance of an additional band in the spectrum related to the luminescence of the bismuth centres of the BiGeSbO6 host. An evaluation of the colour coordinates (CIE 1931) of the Bi1-xPrxGeSbO6 luminescence showed that the colour of the radiation depends on the praseodymium content: as the praseodymium content increases, the luminescence changes from orange (x = 0.005, 0.01) to yellow-green (x = 0.05–0.5). Broadband thermal emission is observed for Bi0.5Pr0.5GeSbO6 under laser excitation with λ = 457 nm and a power density of J = 6 kW/cm2.
- Published
- 2021
4. Unusual magnetic properties and thermal expansion in chromium pyrochlores Ln2CrTaO7, Ln = Y, Sm, Gd
- Author
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O.G. Ellert, A. V. Egorysheva, Roman Svetogorov, E.F. Popova, and D. I. Kirdyankin
- Subjects
010302 applied physics ,Phase transition ,Materials science ,Spin glass ,Rietveld refinement ,Pyrochlore ,02 engineering and technology ,engineering.material ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,XANES ,Electronic, Optical and Magnetic Materials ,Magnetization ,Crystallography ,0103 physical sciences ,engineering ,Antiferromagnetism ,0210 nano-technology - Abstract
New complex Cr-containing pyrochlores Ln2CrTaO7, Ln = Y, Sm, Gd, were synthesized. The Rietveld refinement of the Ln2CrTaO7 composition confirmed the pyrochlore type of the structure. The Cr3+ oxidation state is corroborated by XANES spectra. The detailed study of DC and AC magnetization of Ln2CrTaO7, Ln = Y, Sm, Gd, was carried out in the temperature range 2–300 K and magnetic field up to 5 T. FM phase transitions at 143, 192, and 163 K were observed in pyrochlores with Y, Sm, and Gd, respectively. It is shown that these transitions are due to canted antiferromagnetism or weak-ferromagnetism in the Ln2CrTaO7 pyrochlores. AFM interactions between Ln- and Cr-sublattices in Sm2CrTaO7 and Gd2CrTaO7 causes AFM transition at T = 42 K, after which magnetization continues increasing. Unusual magnetic properties were observed for Gd2CrTaO7 at low temperatures. Competitive FM and AFM interactions in Cr-and Gd-sublattice give rise to the occurrence of reentrant spin glass at T
- Published
- 2020
5. Magnetic properties of Pr2–x Fe1 + x SbO7 and Bi2–x Ln x FeSbO7 (Ln = La, Pr) pyrochlore solid solutions
- Author
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T. D. Dudkina, A. A. Berseneva, O. M. Gaitko, Yu. V. Maksimov, O.G. Ellert, and A. V. Egorysheva
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Materials science ,Spin glass ,Condensed matter physics ,General Chemical Engineering ,Metals and Alloys ,Pyrochlore ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetic susceptibility ,0104 chemical sciences ,Ion ,Bismuth ,Inorganic Chemistry ,Crystallography ,Paramagnetism ,Octahedron ,chemistry ,Materials Chemistry ,engineering ,0210 nano-technology ,Solid solution - Abstract
The Bi–La–Fe–Sb–O, Pr–Fe–Sb–O, and Bi–Pr–Fe–Sb–O systems have been shown to contain pyrochlore solid solutions. We have determined the limits of the Pr2–xFe1 + xSbO7 and Bi2–xLnxFeSbO7 (Ln = La, Pr) solid solutions and shown that there is no compound corresponding to the “ideal” composition Pr2FeSbO7. Analysis of the magnetic properties of the synthesized compounds indicates that rare earth substitution for bismuth ions has no effect on the spin glass transition and that the spin glass state is only determined by the interaction between the Fe3+ spins on the octahedral site. The Pr3+ paramagnetic ion in Pr2–xFe1 + xSbO7 does not participate in the formation of the spin glass state but makes a paramagnetic contribution to the total magnetic susceptibility, which is especially significant at low temperatures.
- Published
- 2016
6. Thermal behavior of borate BaBiBO4
- Author
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V. G. Zalesskii, Stanislav K. Filatov, V. D. Volodin, A. V. Egorysheva, S. N. Volkov, and Rimma S. Bubnova
- Subjects
Materials science ,Thermodynamics ,Mineralogy ,Dielectric ,Atmospheric temperature range ,Condensed Matter Physics ,Heat capacity ,Thermal expansion ,Dielectric spectroscopy ,Condensed Matter::Materials Science ,Differential scanning calorimetry ,Negative thermal expansion ,Materials Chemistry ,Ceramics and Composites ,Thermomechanical analysis - Abstract
The thermal behavior of barium and bismuth borate BaBiBO4 is studied by X-ray powder and single-crystal diffraction in a wide temperature range, as well as by the methods of differential scanning calorimetry and dielectric spectroscopy. Thermal expansion is anisotropic, which is caused by the orientation of BO3 boron-oxygen groups. With increasing temperature, the degree of anisotropy of thermal expansion increases up to negative. In the temperature range of 700–800 K, an anomaly of the dielectric properties is observed, accompanied by the change of the temperature dependence of the coefficients of thermal expansion and the heat capacity.
- Published
- 2015
7. New complex bismuth oxides in the Bi2O3–NiO–Sb2O5 system and their properties
- Author
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Ya. V. Zubavichus, A. V. Egorysheva, O.G. Ellert, O.M. Gajtko, Roman Svetogorov, Nikolay N. Efimov, and V. Yu. Murzin
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Materials science ,Absorption spectroscopy ,Rietveld refinement ,Pyrochlore ,engineering.material ,Condensed Matter Physics ,Magnetic susceptibility ,Electronic, Optical and Magnetic Materials ,X-ray absorption fine structure ,Inorganic Chemistry ,Paramagnetism ,Crystallography ,Materials Chemistry ,Ceramics and Composites ,engineering ,Diffuse reflection ,Physical and Theoretical Chemistry ,Solid solution - Abstract
Phase equilibria in the Bi2O3–NiO–Sb2O5 system have been investigated. The isothermal section of the system (650°) has been constructed. For the first time the existence of the pyrochlore structure solid solution, (Bi2−xNix)Ni2/3−ySb4/3+yO7±δ, x=0.1−0.35, y=0−0.1, and a new compound Bi3Ni2/3Sb7/3O11 of KSbO3 structure type have been discovered. The structures and properties of these compounds were studied by XRD, XAFS, diffuse reflection spectroscopy and magnetic methods. Rietveld refinement of synchrotron radiation-based powder XRD data for pyrochlore sample of 38.43Bi2O3–33.0NiO–28.57Sb2O5 composition and Bi3Ni2/3Sb7/3O11 compound was performed. The best possible refinement of the positional parameters for both pyrochlore and Bi3Ni2/3Sb7/3O11 structures was achieved for disordered models. Magnetic, diffuse reflection and an X-ray absorption spectroscopy study confirmed that in both compounds nickel ions are mainly in a 2+ oxidation state. According to magnetic data, Bi1.84Ni0.16(Ni0.63Sb1.37)O7 pyrochlore and Bi3Ni2/3Sb7/3O11 are overall paramagnetic in nature.
- Published
- 2015
8. The Bi2O3–Fe2O3–Sb2O5 system phase diagram refinement, Bi3FeSb2O11 structure peculiarities and magnetic properties
- Author
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O.M. Gajtko, A. V. Egorysheva, Anastasia V. Grigorieva, Ya. V. Zubavichus, O.G. Ellert, Nikolay N. Efimov, and Roman Svetogorov
- Subjects
Chemistry ,Pyrochlore ,engineering.material ,Atmospheric temperature range ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,Magnetization ,symbols.namesake ,Materials Chemistry ,Ceramics and Composites ,engineering ,symbols ,Antiferromagnetism ,Physical and Theoretical Chemistry ,Ternary operation ,Raman spectroscopy ,Phase diagram ,Solid solution - Abstract
The refinement of the Bi2O3–Fe2O3–Sb2O5 system phase diagram has been performed and the existence of the two ternary compounds has been confirmed. The first one with a pyrochlore-type structure (sp. gr. Fd 3m) exists in the wide solid solution region, (Bi2−xFex)Fe1+ySb1−yO7±δ, where x=0.1–0.4 and y=−0.13–0.11. The second one, Bi3FeSb2O11, corresponds to the cubic KSbO3-type structure (sp. gr. Pn 3) with unit cell parameter a=9.51521(2) A. The Rietveld structure refinement showed that this compound is characterized by disordered structure. The Bi3FeSb2O11 factor group analysis has been carried out and a Raman spectrum has been investigated. According to magnetization measurements performed at the temperature range 2–300 K it may be concluded that the Bi3FeSb2O11 magnetic properties can be substantially described as a superposition of strong short-range antiferromagnetic exchange interactions realizing inside the [(FeSb2)O9] 3D-framework via different pathways.
- Published
- 2015
9. Magnetic glass–ceramics containing multiferroic BiFeO3 crystals
- Author
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Peter M. Rafailov, O.G. Ellert, Nikolay N. Efimov, Teodor Milenov, Vladimir M. Novotortsev, G. V. Avdeev, and A. V. Egorysheva
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Materials science ,Mineralogy ,General Chemistry ,Condensed Matter Physics ,Microstructure ,law.invention ,symbols.namesake ,Dendrite (crystal) ,Crystallinity ,law ,visual_art ,visual_art.visual_art_medium ,symbols ,General Materials Science ,Multiferroics ,Ceramic ,Crystallite ,Crystallization ,Composite material ,Raman spectroscopy - Abstract
A new composite material consisting of BiFeO3 crystallites inside a nonmagnetic glass-like matrix has been synthesized using the glass crystallization method. The phase equilibrium and glass formation region of the Bi2O3–Fe2O3–B2O3 system (0–50 mol % B2O3) have been investigated. The optimal compositions for glass–ceramic synthesis are within the 25–85 mol % BiFeO3 range on the Bi4B2O9–BiFeO3 section. The obtained ceramics were studied by X-ray diffraction, Raman spectroscopy, microscopic and magnetic methods. It was shown that the BiFeO3 crystallites grow according to a dendrite mechanism resulting in anisotropic glass–ceramic. Magnetic properties of the synthesized samples depend upon their morphology and crystallinity.
- Published
- 2015
10. Subsolidus phase equilibria and magnetic characterization of the pyrochlore in the Bi2O3–Fe2O3–Sb2O system
- Author
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V. D. Volodin, Yu. V. Maksimov, Nikolay N. Efimov, A. V. Egorysheva, O.G. Ellert, and Vladimir M. Novotortsev
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Condensed matter physics ,Chemistry ,Mechanical Engineering ,Metals and Alloys ,Pyrochlore ,engineering.material ,Crystallography ,chemistry.chemical_compound ,Mechanics of Materials ,Superexchange ,Ternary compound ,Phase (matter) ,Materials Chemistry ,engineering ,Antiferromagnetism ,Powder diffraction ,Solid solution ,Phase diagram - Abstract
The subsolidus phase equilibria of the Bi 2 O 3 –Fe 2 O 3 –Sb 2 O x system have been investigated by X-ray powder diffraction. The isothermal section of the system at 775–800 °C has been constructed. It can be represented by 9 phase assemblage triangles. Ternary compound formation is limited to pyrochlore which forms a substantial solid solution region of Bi-deficient compositions relative to Bi 2 FeSbO 7 . As follows from the phase diagram, approximately 7–25% of Bi positions in pyrochlore may be occupied with Fe 3+ ions that was confirmed by Mossbauer data. Magnetic measurements were carried out on the pyrochlore specimen of quasi-chemical formula (Bi 1.8 Fe 0.2 )(FeSb)O 7 . The existence of the strong short-range antiferromagnetic superexchange interactions and spin-glass magnetic transition at around 9 K were revealed.
- Published
- 2013
11. Preparation, crystal structure and thermal expansion of a novel layered borate, Ba2Bi3B25O44
- Author
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Stanislav K. Filatov, S. N. Volkov, Maria G. Krzhizhanovskaya, Sergey V. Krivovichev, Rimma S. Bubnova, and A. V. Egorysheva
- Subjects
Materials science ,Inorganic chemistry ,chemistry.chemical_element ,Barium ,Crystal structure ,Condensed Matter Physics ,Thermal expansion ,Electronic, Optical and Magnetic Materials ,Bismuth ,Inorganic Chemistry ,chemistry ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Physical chemistry ,Physical and Theoretical Chemistry ,Anisotropy ,Boron ,Stoichiometry - Abstract
Single crystals of a new compound, Ba2Bi3B25O44, were grown by cooling a melt of non- stoichiometric composition. The crystal structure was solved by direct methods and refined to R ¼ 0.030
- Published
- 2012
12. Crystal growth, crystal structure of new polymorphic modification, β-Bi2B8O15 and thermal expansion of α-Bi2B8O15
- Author
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Stanislav K. Filatov, Rimma S. Bubnova, Sergey V. Krivovichev, J. V. Alexandrova, and A. V. Egorysheva
- Subjects
Chemistry ,Space group ,Crystal growth ,Crystal structure ,Triclinic crystal system ,Atmospheric temperature range ,Condensed Matter Physics ,Thermal expansion ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,Crystal twinning ,Powder diffraction - Abstract
Single crystals of α- and β-polymorphs of Bi2B8O15 were grown by Czochralski method from a charge of the stoichiometric composition. The crystal structure of β-Bi2B8O15 was solved by direct methods from a twinned crystal and refined to R1=0.081 (wR=0.198) on the basis of 1584 unique observed reflections (I>2σ(I)). The compound is triclinic, space group P 1 ¯ , a=4.3159(8), b=6. 4604(12), c=22.485(4) A, α=87.094(15)°, β=86.538(15)°, γ=74.420(14)°, V=602.40(19) A3, Z=2. The B–O layered anion of β-Bi2B8O15 is topologically identical to the anion of α-Bi2B8O15 but the orientation of neighboring layers is different. Thermal expansion of α-Bi2B8O15 has been investigated by X-ray powder diffraction in air in temperature range from 20 to 700 °C. It is strongly anisotropic, which can be explained by the hinge mechanism applied to chains of Bi–O polyhedra. While the anisotropy of thermal expansion is rather high, the volume thermal expansion coefficient αV=40×106 °C−1 for α-Bi2B8O15 is close to those of other bismuth borates.
- Published
- 2010
13. Synthesis, crystal structure and thermal behavior of a novel oxoborate SrBi2B4O10
- Author
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A. V. Egorysheva, Rimma S. Bubnova, Maria G. Krzhizhanovskaya, V. D. Volodin, Michael S. Kozin, and Stanislav K. Filatov
- Subjects
Materials science ,chemistry.chemical_element ,Calorimetry ,Thermal treatment ,Crystal structure ,Atmospheric temperature range ,Triclinic crystal system ,Condensed Matter Physics ,Thermal expansion ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Crystallography ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Physical and Theoretical Chemistry ,Boron ,Powder diffraction - Abstract
A new compound, SrBi 2 B 4 O 10 , has been grown by cooling a melt with the stoichiometric composition. It is triclinic, P −1, a =6.819(1), b =6.856(1), c =9.812(2) A, α= 96.09(1), β =109.11(1), γ =101.94(1)°, V =416.5(1) A 3 , Z =2. The crystal structure of the compound has been solved by direct methods and refined to R 1 =0.050 (w R 2 =0.128). The structure contains Bi–O pseudolayers build up from Bi–O chains involving oxocentred OBi 3 triangles. Sr atoms and [B 4 O 9 ] 6− isolated anions (4B:3 Δ □: Δ □> Δ ) are located between the Bi–O packages. The thermal treatment as well as DSC experiment showed that the compound melts above 800 °C presumably according to the peritectic reaction: SrBi 2 B 4 O 10 ↔ SrB 2 O 4 +SrB 4 O 7 + Liquid. According to high-temperature X-ray powder diffraction study thermal expansion of SrBi 2 B 4 O 10 structure is anisotropic ( α 11 =13, α 22 =9, α 33 =2, α V =24×10 −6 °C −1 ).
- Published
- 2009
14. An optical excitation study of Ru-, Rh-, Re- and Os-doped Bi12SiO20 crystals
- Author
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A. Ya. Vasil'ev, M. M. Gospodinov, Peter M. Rafailov, V. M. Skorikov, M. N. Veleva, A. V. Egorysheva, Teodor Milenov, and T. D. Dudkina
- Subjects
Photocurrent ,Absorption spectroscopy ,Chemistry ,Electron capture ,Impurity ,Attenuation coefficient ,Doping ,Analytical chemistry ,Condensed Matter Physics ,Absorption (electromagnetic radiation) ,Order of magnitude ,Electronic, Optical and Magnetic Materials - Abstract
We studied the influence of doping with 4d and 5d elements on the optical and photo-induced properties of Bi12SiO20 (BSO) crystals. Doping with Ru, Rh and Re does not significantly influence BSO absorption spectra as well as photo-induced absorption and photocurrent in BSO. On the other hand, doping with Os with concentration of 0.0004 mass% increases by more than an order of magnitude the illumination response time, the strength of the photochromic effect and photocurrent, all this being accompanied by only a slight change of the absorption coefficient as compared to undoped BSO. The observed effects are explained in the framework of the Rose model assuming that doping with Os creates deep levels in the gap that act as recombination centers with a very little cross-section of electron capture. We also studied the kinetic curves of photocurrent increase and decrease in BSO:Os which enabled us to determine the magnitude of the cross-section of a photon capture at an impurity center. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
- Published
- 2007
15. Polarization effects at two-beam interaction on reflection holographic gratings in sillenite crystals
- Author
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A. V. Egorysheva, Yu. N. Kulchin, V. G. Sibagatulina, Roman V. Romashko, D. S. Baklanov, Vladimir Volkov, M. A. Dubtsov, Stanislav M. Shandarov, Yu. F. Kargin, and N. I. Burimov
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Physics ,Birefringence ,business.industry ,Holography ,Physics::Optics ,Radiation ,Condensed Matter Physics ,Polarization (waves) ,Laser ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,law.invention ,Crystal ,Optics ,law ,Vector field ,Photonics ,business ,Instrumentation - Abstract
The polarization structure of the signal wave that interacts with a circularly polarized pump wave on the reflection holographic gratings in the (112)-, (111)-, and (110)-cut Bi12TiO20 (BTO) crystals is experimentally and theoretically analyzed. An analytical expression for the vector field of the signal wave that is valid for an arbitrary orientation of the cubic refractive crystal is derived using approximation of the nondepleting circularly polarized pump wave. The contribution of the absorption component of the reflection hologram into the counter interaction is estimated for the crystals under study using the approximation of the experimental data with theoretical curves. Based on the experiments with incoherent quasi-monochromatic radiation, it is demonstrated that the real BTO crystals exhibit weak induced linear birefringence.
- Published
- 2007
16. Circular dichroism spectra of synthetic amethyst crystals
- Author
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A. A. Mar'in, E. V. Fedotov, Vladimir I. Burkov, A. V. Egorysheva, and Yu. F. Kargin
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Crystal ,Crystallography ,Chemistry ,engineering ,General Materials Science ,General Chemistry ,Electronic structure ,Amethyst ,engineering.material ,Condensed Matter Physics ,Circular dichroism spectra - Abstract
The axial circular-dichroism spectrum of a synthetic amethyst crystal has been studied for the first time. Bands both of the positive and negative signs are revealed. New information on the color centers of amethyst and their electronic structure is obtained.
- Published
- 2005
17. Growth and characterization of doped Bi12TiO20 single crystals
- Author
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V. M. Skorikov, Yu. F. Kargin, Stanislav M. Shandarov, A. V. Egorysheva, Vladimir Volkov, A. E. Mandel, and Vladimir I. Burkov
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Flux method ,Circular dichroism ,Materials science ,Photoconductivity ,Doping ,Analytical chemistry ,Mineralogy ,Grating ,Condensed Matter Physics ,Inorganic Chemistry ,Coupling (electronics) ,Reflection (mathematics) ,Materials Chemistry ,Absorption (electromagnetic radiation) - Abstract
Single crystals of Bi 12 TiO 20 doped with Cu, Ca, Zn, Cd, B, Al, Ga, V, P, Nb, Cr, Mn, Fe, Co, Ni, and their mixtures were grown by a conventional high-temperature flux method. Absorption, circular dichroism, light-induced absorption, optical activity, photoconductivity, dark conductivity and the two-beam coupling on the reflection grating are studied.
- Published
- 2005
18. The growth of photorefractive planar BTO/BSO and BTO/BGO waveguide
- Author
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Yu. F. Kargin, Marina N. Frolova, A. V. Egorysheva, Detlef Kip, M. V. Borodin, Vladimir Volkov, Stanislav M. Shandarov, and Vladimir Shandarov
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Materials science ,business.industry ,Time evolution ,Photorefractive effect ,Substrate (electronics) ,Condensed Matter Physics ,Waveguide (optics) ,law.invention ,Inorganic Chemistry ,Optics ,Planar ,law ,Materials Chemistry ,Optoelectronics ,Crystallization ,Thin film ,business ,Absorption (electromagnetic radiation) - Abstract
The Bi 12 TiO 20 thin films with high optical quality were grown from the melt on a substrate of Bi 12 SiO 20 and Bi 12 GeO 20 single crystals by two methods: LPE and crystallization from finite volume (CFV). The results of experimental investigation of time evolution of light-induced absorption in BTO:Cu waveguide are presented. All structures show a nearly equidistant spectrum of n eff with intervals from 2×10 −3 to 5×10 −3 . The time evolution of light-induced absorption is qualitatively different for the lowest and the highest modes in the waveguide.
- Published
- 2005
19. Electrical conductivity of Bi12SiO20 single crystals doped with Os, Re, Ru, and Rh
- Author
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V. M. Skorikov, Yu. F. Kargin, A. Ya. Vasil'ev, Teodor Milenov, D. P. Petrova, M. N. Veleva, Marin Gospodinov, and A. V. Egorysheva
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Inorganic Chemistry ,Materials science ,Condensed matter physics ,Electrical resistivity and conductivity ,Condensed Matter::Superconductivity ,General Chemical Engineering ,Doping ,Materials Chemistry ,Metals and Alloys ,Charge (physics) ,Conductivity - Abstract
Bi12 SiO20 crystals doped with Os, Re, Ru, and Rh were grown by the Czochralski technique, and their conductivity (real and imaginary parts) was measured as a function of temperature and frequency. The results are interpreted as evidence that the charge transport in the crystals is due to hopping along chains of localized states.
- Published
- 2005
20. Vibrational spectra of crystals of bismuth borates
- Author
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A. V. Egorysheva, Yu. F. Kargin, V. V. Koltashev, Victor G. Plotnichenko, and Vladimir I. Burkov
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Crystallography ,Chemistry ,Physical chemistry ,chemistry.chemical_element ,General Materials Science ,General Chemistry ,Condensed Matter Physics ,Boron ,Spectral line ,Vibrational spectra ,Bismuth - Abstract
The vibrational spectra of crystals of bismuth borates Bi24B2O39, Bi4B2O9, BiBO3, and Bi2B8O15 were obtained for the first time, and the spectra of Bi3B5O12 and BiB3O6 crystals measured in the range 30–1600 cm−1 at room temperature were refined. The lines observed were assigned to the corresponding vibrational transitions on the basis of the theoretical group analysis and comparison of the obtained results with the vibrational spectra of borates of different composition. The complication of the structure of bismuth borates with increasing content of B2O3 was traced by the example of vibrational spectra.
- Published
- 2005
21. Local Magnetic Fields in Some Bismuth-Based Diamagnets
- Author
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M. P. Shlikov, Yu. F. Kargin, V.G. Orlov, V. G. Morgunov, A. V. Egorysheva, and E. A. Kravchenko
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Nuclear and High Energy Physics ,Condensed matter physics ,chemistry.chemical_element ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Spectral line ,Bismuth ,Magnetic field ,law.invention ,SQUID ,Paramagnetism ,chemistry ,law ,Diamagnetism ,Physical and Theoretical Chemistry ,Nuclear quadrupole resonance ,Spectroscopy - Abstract
Evidence that local ordered magnetic fields from 30 to 250 G exist in bismuth-based diamagnetic compounds comprising neither d- nor f-elements was given by 209Bi NQR spectroscopy and supported by SQUID measurements of α-Bi2O3. The NQR experiments involved a study of the zero-field line shapes, analysis of the Zeeman-perturbed patterns, and examination of the zero-field spin-echo envelopes in single crystals and powders. The results of the experiments followed by computer modeling of the observed spectra were interpreted assuming that ordered magnetic fields are located at the bismuth sites in α-Bi2O3, Bi3O4Br, Bi2Al4O9, Bi4Ge3O12, Bi2Ge3O9 and perhaps in Bi3B5O12. A survey of the related 209Bi NQR data is here presented.
- Published
- 2004
22. The study of Bi3B5O12: synthesis, crystal structure and thermal expansion of oxoborate Bi3B5O12
- Author
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Natalia Sennova, A. V. Egorysheva, Stanislav K. Filatov, Yury F. Kargin, Yurij Shepelev, and Rimma S. Bubnova
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Chemistry ,Infrared spectroscopy ,Cleavage (crystal) ,Crystal structure ,Condensed Matter Physics ,Thermal expansion ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Tetragonal crystal system ,Crystallography ,Zigzag ,X-ray crystallography ,Materials Chemistry ,Ceramics and Composites ,Orthorhombic crystal system ,Physical and Theoretical Chemistry - Abstract
The paper presents a new data on the crystal structure, thermal expansion and IR spectra of Bi 3 B 5 O 12 . The Bi 3 B 5 O 12 single crystals were grown from the melt of the same stoichiometry by Czochralski technique. The crystal structure of Bi 3 B 5 O 12 was refined in anisotropic approximation using single-crystal X-ray diffraction data. It is orthorhombic, Pnma , a =6.530(4), b =7.726(5), c =18.578(5) A, V =937.2(5) A 3 , Z =4, R =3.45%. Bi 3+ atoms have irregular coordination polyhedra, Bi(1)O 6 ( d (B–O)=2.09–2.75 A) and Bi(2)O 7 ( d (B–O)=2.108–2.804 A). Taking into account the shortest bonds only, these polyhedra are considered here as trigonal Bi(1)O 3 (2.09–2.20 A) and tetragonal Bi(2)O 4 (2.108–2.331 A) irregular pyramids with Bi atoms in the tops of both pyramids. The BiO 4 polyhedra form zigzag chains along b -axis. These chains alternate with isolated anions [B 2 IV B 3 III O 11 ] 7− through the common oxygen atoms to form thick layers extended in ab plane. A perfect cleavage of the compound corresponds to these layers and an imperfect one is parallel to the Bi–O chains. The Bi 3 B 5 O 12 thermal expansion is sharply anisotropic ( α 11 ≈ α 22 =12, α 33 =3×10 −6 °C −1 ) likely due to a straightening of the flexible zigzag chains along b -axis and decreasing of their zigzag along c -axis. Thus the properties like cleavage and thermal expansion correlate to these chains.
- Published
- 2004
23. Absorption and circular-dichroism spectra of iron-doped berlinite crystals
- Author
-
P. P. Shvanskii, A. V. Egorysheva, Yu. F. Kargin, Vladimir I. Burkov, and A. I. Motchanyi
- Subjects
Range (particle radiation) ,Circular dichroism ,Berlinite ,Iron doped ,Chemistry ,Analytical chemistry ,Physics::Optics ,General Chemistry ,Condensed Matter Physics ,Circular dichroism spectra ,Spectral line ,Condensed Matter::Materials Science ,Atomic electron transition ,General Materials Science ,Absorption (chemistry) - Abstract
Absorption and circular-dichroism spectra of iron-doped AlPO4 crystals have been studied. For the first time, the experimental data on the electronic states of the [FeO4]5− complex are obtained in the range from 190 to 350 nm with due regard for the interactions that cannot be described within the one-electron approximation. The bands observed in the absorption and circular-dichroism spectra are attributed to corresponding electronic transitions. The advantages of the use of crystal-field-induced circular dichroism in comparison with other spectroscopic methods in the analysis of the electronic states of impurity ions in gyrotropic crystalline matrices are considered on the [FeO4]5− complex.
- Published
- 2002
24. [Untitled]
- Author
-
Yu. F. Kargin, A. Ya. Vasil'ev, A. V. Egorysheva, V. M. Skorikov, and Vladimir I. Burkov
- Subjects
Circular dichroism ,Magnetic moment ,Condensed matter physics ,Chemistry ,General Chemical Engineering ,Metals and Alloys ,Inorganic Chemistry ,symbols.namesake ,Dipole ,Stark effect ,Atomic electron transition ,Materials Chemistry ,symbols ,Atomic physics ,Ground state ,Anisotropy ,Magnetic dipole - Abstract
The absorption and circular dichroism spectra of Nd-doped Bi12SiO20 crystals were measured in the range 10 000 to 20 000 cm–1. The spectra showed electronic transitions related to only one type of Nd-related center: Nd substituting for Bi in position with symmetry C1. The bands due to the transitions from the first Stark component of the ground state to Stark components of excites states (4I9/2 → 4G5/2 , 4I9/2 → 2G7/2 , and 4I9/2 → 4G7/2) were analyzed in detail. The dipole strength D0k , rotatory power R0k , and anisotropy factor G0k of these transitions were calculated. The intensities of transitions to Stark components were shown to vary by more than one order of magnitude within an excited-state multiplet. The anisotropy factors of the 4I9/2 → 2G7/2 and 4I9/2 → 4G7/2 transitions, allowed in the magnetic dipole approximation, are, on the average, larger than that of the 4I9/2 → 4G5/2 transition, which points to a significant contribution of the magnetic moment (λ λ2) to the total intensity of the transition.
- Published
- 2002
25. Raman scattering in monocrystal Bi3B5O12
- Author
-
Victor G. Plotnichenko, V. I. Burkov, Vladimir S. Gorelik, Yu. F. Kargin, A. V. Egorysheva, and V. V. Koltashev
- Subjects
Materials science ,Solid-state physics ,business.industry ,Radiation ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,X-ray Raman scattering ,Optics ,symbols ,Coherent anti-Stokes Raman spectroscopy ,Raman spectroscopy ,business ,Raman scattering - Abstract
Raman spectra of a Bi3B5O12 monocrystal are investigated for the first time and compared with the Raman spectra of crystals α-Bi2O3 and Bi12SiO20. The most intensive lines observed in the Raman spectrum of Bi3B5O12 are identified. Promising prospects of use of Bi3B5O12 crystals as SRS converters of radiation are shown.
- Published
- 2001
26. Raman scattering in sillenite-type crystals
- Author
-
Yu. F. Kargin, Vladimir I. Burkov, A. V. Egorysheva, Vladimir S. Gorelik, and A. V. Chervyakov
- Subjects
Materials science ,Analytical chemistry ,General Chemistry ,Condensed Matter Physics ,Polarization (waves) ,Molecular physics ,Spectral line ,symbols.namesake ,X-ray Raman scattering ,symbols ,General Materials Science ,Physics::Atomic Physics ,Coherent anti-Stokes Raman spectroscopy ,Raman spectroscopy ,Raman scattering - Abstract
The Raman spectra of Bi24AlPO40 and Bi38ZnO58 crystals have been studied for the first time. The polarization Raman spectra of Bi12GeO20, Bi12TiO20, Bi24AlPO40, and Bi38ZnO58 crystals are also studied. The lines in the Raman spectra of Bi12TiO20, Bi24AlPO40, and Bi38ZnO58 are identified and compared with the lines of the Bi12GeO20 spectra studied earlier. It is shown that the differences in the Raman spectra of the crystals studied are associated with the specific features of their atomic structures.
- Published
- 2001
27. Optical and chiro-optical properties of crystals with sillenite structure
- Author
-
Yu. F. Kargin, A. V. Egorysheva, and Vladimir I. Burkov
- Subjects
Photochromism ,Circular dichroism ,Crystallography ,Chemistry ,Atomic electron transition ,General Materials Science ,General Chemistry ,Crystal structure ,Optical rotation ,Condensed Matter Physics ,Absorption (electromagnetic radiation) ,Spectral line ,Molecular electronic transition - Abstract
The experimental data on the optical and chiro-optical properties of crystals with the sillenite structure Bi12MxO20 ± δ (M= elements of II–VIII groups) have been reviewed. The relations between the changes in the chemical composition, the crystal structure of Bi12MxO20 ± δ compounds, absorption, circular dichroism, and optical rotation spectra of sillenites have been established. A model taking into account the contribution of the electronic transitions of optically active tetrahedral [MO4]n− complexes to the total optical rotation in sillenites is suggested. The data on the state (oxidation degree) and the recharging processes of 3d-elements in sillenites are systematized. The models of optical centers responsible for the photochromic effect in sillenites are critically analyzed.
- Published
- 2001
28. Lattice distortions in a crystal caused by doping with copper
- Author
-
Peter M. Rafailov, V. M. Skorikov, Christian Thomsen, Marin Gospodinov, Teodor Milenov, Rosica Petrova, and A. V. Egorysheva
- Subjects
Scattering ,Chemistry ,Doping ,Analytical chemistry ,chemistry.chemical_element ,General Chemistry ,Crystal structure ,Condensed Matter Physics ,Copper ,Crystal ,Condensed Matter::Materials Science ,Crystallography ,symbols.namesake ,Lattice constant ,Impurity ,Condensed Matter::Superconductivity ,Materials Chemistry ,symbols ,Raman spectroscopy - Abstract
Bi12SiO20 crystals doped with Cu were grown by the Czochralski method along 〈 001 〉 from a melt. The concentration of the impurities was determined by electro–thermal and flame atomic absorption spectroscopy. The lattice parameter a o = 10.165 A was determined by single-crystal diffractometry. Results from Raman measurements in different scattering configurations lead to the conclusion that distinguishable structural distortions of the bismuth–oxygen framework of the sillenite lattice take place due to Cu doping.
- Published
- 2009
29. Structural changes in metastable γ-Na2B4O7 between -150 °C and 720 °C
- Author
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Rimma S. Bubnova, Barbara Albert, Stanislav K. Filatov, A. Egorysheva, Gerhard Cordier, and M. Fofanova
- Subjects
Inorganic Chemistry ,Crystallography ,Materials science ,chemistry ,Metastability ,chemistry.chemical_element ,General Materials Science ,Condensed Matter Physics ,Boron ,Thermal expansion - Published
- 2013
30. Local Magnetic Fields in Some Bismuth-Based Diamagnets. A Survey of NQR Data
- Author
-
Yu. F. Kargin, M. P. Shlikov, V. G. Orlov, V. G. Morgunov, E. A. Kravchenko, and A. V. Egorysheva
- Subjects
SQUID ,Condensed matter physics ,chemistry ,law ,Diamagnetism ,chemistry.chemical_element ,Nuclear quadrupole resonance ,Spectroscopy ,Spectral line ,Bismuth ,Magnetic field ,Line (formation) ,law.invention - Abstract
Evidence that local ordered magnetic fields from 30 to 250 G exist in bismuth-based diamagnetic compounds comprising neither d- nor f-elements was given by 209Bi NQR spectroscopy and supported by SQUID measurements of a-Bi2O3. The NQR experiments involved a study of the zero-field line shapes, analysis of the Zeeman-perturbed patterns, and examination of the zero-field spin-echo envelopes in single crystals and powders. The results of the experiments followed by computer modeling of the observed spectra were interpreted assuming that ordered magnetic fields are located at the bismuth sites in a-Bi2O3, Bi3O4Br, Bi2Al4O9, Bi4Ge3O12, Bi2Ge3O9 and perhaps in Bi3B5O12. A survey of the related 209Bi NQR data is here presented.
- Published
- 2008
31. Contradirectional two-wave interaction in a sillenite crystals doped by different impurties
- Author
-
Stanislav M. Shandarov, V.N. Navniko, V. V. Shepelevich, Yu. F. Kargin, Vladimir Volkov, A. M. Plesovskikh, A. E. Mandel, A. V. Egorysheva, and A.G. Mart'yanov
- Subjects
Materials science ,Condensed matter physics ,business.industry ,Doping ,Physics::Optics ,Photorefractive effect ,Reflection (mathematics) ,Impurity ,Condensed Matter::Superconductivity ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,business ,Absorption (electromagnetic radiation) ,Laser beams - Abstract
In this work we studied experimentally the dynamics of beam-coupling amplification on a reflection gratings at light-induced absorption in Bi12TiO20 crystals doped by different impurities. Doping with different impurities modifies the photorefractive properties of these crystals
- Published
- 2004
32. Tetrahedral Cr4+ and Cr5+ in Bi12TiO20 single crystals
- Author
-
Carlos Zaldo, Carmen Coya, Vladimir Volkov, and A. V. Egorysheva
- Subjects
Absorption spectroscopy ,Annealing (metallurgy) ,Stereochemistry ,Bismuth titanate ,Near-infrared spectroscopy ,Analytical chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Superposition principle ,chemistry.chemical_compound ,Chromium ,chemistry ,Lattice (order) ,Molecular vibration - Abstract
Cr-doped Bi12TiO20 (BTO) single crystals have been grown by the Czochralski technique. The optical absorption at 4.2 K of as-grown crystals is compared to that observed after vacuum annealing of the samples. This treatment modifies the visible and near infrared optical absorption. The absorption spectrum of Cr-doped BTO crystals before vacuum annealing is interpreted as the superposition of the crystal-field transition bands of (CrO4)4- and (CrO4)3- and charge transfer bands of (CrO4)3-. Annealing in vacuum leads to Cr5+ → Cr4+ conversion. Chromium reduction to lower oxidation states has not been observed. The optical absorption shows a vibrational character. The energy shifts of Cr4+ bands are as expected from the coupling with the T2(v3) fundamental mode of (CrO4)4- clusters. On the other hand, it is proposed that the series of sharp lines observed in the 9500 to 11500 cm-1 range arises from the interaction with a vibration of about 300 cm-1, which seems to be the T2(v4) fundamental mode of (CrO4)3- and with the lattice modes.
- Published
- 1998
33. NQR indications of unconventional magnetism in some bismuth-based diamagnets
- Author
-
Yu. F. Kargin, E. A. Kravchenko, A. V. Egorysheva, M. P. Shlikov, V.G. Orlov, and V. G. Morgunov
- Subjects
Condensed matter physics ,Solid-state physics ,Magnetism ,Chemistry ,Spin echo ,Resonance ,Nuclear quadrupole resonance ,Single crystal ,Atomic and Molecular Physics, and Optics ,Spectral line ,Magnetic field - Abstract
An evidence that local ordered magnetic fields from 30 to 200 G exist in diamagnets α-Bi2O3, Bi3O4Br, Bi4Ge3O12, Bi2Al4O9 which comprise neither d- nor f-elements was earlier given by the zerofield and Zeeman-perturbed209Bi nuclear quadrupole resonance (NQR) spectra. With a view to find similar spectroscopic effects in other compounds, we examined the209Bi NQR Zeeman-perturbed spectra of the Bi3B5O12 oriented single crystal as well as the zero-field spin echo envelopes in Bi3B5O12 and Bi2Ge3O9. Distinctive modulations were displayed by the zero-field209Bi spin echo envelopes in Bi2Ge3O9 powder. The modeling of the spin echo envelopes within the density matrix formalism explained the observed effect by the presence of local ordered magnetic field of the order of 65 G at the Bi atoms. The zero-field modulations of the209Bi spin echo envelopes were also observed in Bi3B5O12 indicating the presence of the internal source of line splitting. This finding and considerable deviation of the resonance intensity ratios from that in a pure NQR, found in the zero-field209Bi spectrum of the single crystal, were understood as indirect evidences that a local ordered magnetic field exists also in Bi3B5O12. The zero-field209Bi spin echo envelopes assigned to the lines split by the local magnetic fields in α-Bi2O3 and Bi4Ge3O12 were observed to display modulations on the appropriate curves.
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