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Antonov, Viktor

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  • Antonov, Viktor (3)
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Author's Bibliography

X-ray spectra, electron structure and physical properties of the Ce2ScSi2 and СеScSi compounds

Shcherba, Ivan D.; Antonov, Viktor; Noga, Henrik; Uskoković, Dragan; Shpyrka, Zinovija M.; Yatcyk, Bohdan M.

(Belgrade : Materials Research Society of Serbia, 2019)

TY  - CONF
AU  - Shcherba, Ivan D.
AU  - Antonov, Viktor
AU  - Noga, Henrik
AU  - Uskoković, Dragan
AU  - Shpyrka, Zinovija M.
AU  - Yatcyk, Bohdan M.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6681
AB  - Energy structure of the valence band of the Ce2ScSi2 and СеScSi compounds was studied by the methods of the high-energy spectroscopy (XPS, XES and XAS). Dependence of magnetic susceptibility χ(Т) of the Ce2ScSi2 compound within wide temperature range corresponds to the Curie-Weiss law. Based upon temperature dependences χ(Т) and α(Т), together with calculated valence of Ce by the data of the absorption LІІІ –spectroscopy, a conclusion has been made on the existence of the fluctuating transition, «State of intermediate valence - Condo-systems", in the Ce2ScSi2 compound. The calculations of electron energy bands E(k) and partial DOS for Ce2ScSi2 and СеScSi compounds were performed by the semi relativistic linear muffin-tin orbital method without considerations of spin-orbit interactions A satisfactory agreement between theoretical and experimental data is achieved.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of abstracts / Twenty-first Annual Conference YUCOMAT 2019 & Eleventh World Round Table Conference on Sintering WRTCS 2019, Herceg Novi, Montenegro, September 2-6, 2019
T1  - X-ray spectra, electron structure and physical properties of the Ce2ScSi2 and СеScSi compounds
SP  - 109
EP  - 109
ER  - 
@conference{
author = "Shcherba, Ivan D. and Antonov, Viktor and Noga, Henrik and Uskoković, Dragan and Shpyrka, Zinovija M. and Yatcyk, Bohdan M.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6681",
abstract = "Energy structure of the valence band of the Ce2ScSi2 and СеScSi compounds was studied by the methods of the high-energy spectroscopy (XPS, XES and XAS). Dependence of magnetic susceptibility χ(Т) of the Ce2ScSi2 compound within wide temperature range corresponds to the Curie-Weiss law. Based upon temperature dependences χ(Т) and α(Т), together with calculated valence of Ce by the data of the absorption LІІІ –spectroscopy, a conclusion has been made on the existence of the fluctuating transition, «State of intermediate valence - Condo-systems", in the Ce2ScSi2 compound. The calculations of electron energy bands E(k) and partial DOS for Ce2ScSi2 and СеScSi compounds were performed by the semi relativistic linear muffin-tin orbital method without considerations of spin-orbit interactions A satisfactory agreement between theoretical and experimental data is achieved.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of abstracts / Twenty-first Annual Conference YUCOMAT 2019 & Eleventh World Round Table Conference on Sintering WRTCS 2019, Herceg Novi, Montenegro, September 2-6, 2019",
title = "X-ray spectra, electron structure and physical properties of the Ce2ScSi2 and СеScSi compounds",
pages = "109-109"
}

Crystal structure and X-Ray spectroscopic properties of R.E.2Ni12P5 compounds

Scherba, Ivan; Noga, Henrik; Antonov, Viktor; Zhak, Olga; Uskoković, Dragan; Jatcyk, Bohdan M.

(Belgrade : Materials Research Society of Serbia, 2018)

TY  - CONF
AU  - Scherba, Ivan
AU  - Noga, Henrik
AU  - Antonov, Viktor
AU  - Zhak, Olga
AU  - Uskoković, Dragan
AU  - Jatcyk, Bohdan M.
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/3668
AB  - We have studied experimentally and theoretically the electronic structure and x-ray absorption spectrum at the R.E.L3 - edge and x-ray emission spectra of Ni and P in the R.E.2Ni12P5 compounds. Crystal structure of the ternary phosphate Ce2Ni12P5 has been refined using X-ray powder diffraction pattern of the single phase sample with the same nominal composition, and the isotopic structure as for earlier known La2Ni12P5-type has been proved: space group P21/m, formula units Z = 2, lattice parameters are a = 1.07809(2) nm, b = 0.36869(1) nm, c = 1.31490(3) nm, b = 107.776(4), residual R-values are RI = 0.0681, RP = 0.0442 , RwP = 0.0603. The theoretical calculations have been carried out by means of the ab initio fully-relativistic spinpolarized Dirac linear muffin-tin orbital method. The calculations show good agreement with the experimental measurements. R.E.LIII - absorption spectra in ternary R.E.2Ni12P5 compounds were obtained at 78K and 300K using a tube spectrometer equipped with an RKD-01 co-ordinate detector. The mixed valence state of Ce and Eu was obtained in the Ce2Ni12P5 and Eu2Ni12P5 compounds.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018
T1  - Crystal structure and X-Ray spectroscopic properties of R.E.2Ni12P5 compounds
SP  - 109
EP  - 109
ER  - 
@conference{
author = "Scherba, Ivan and Noga, Henrik and Antonov, Viktor and Zhak, Olga and Uskoković, Dragan and Jatcyk, Bohdan M.",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/3668",
abstract = "We have studied experimentally and theoretically the electronic structure and x-ray absorption spectrum at the R.E.L3 - edge and x-ray emission spectra of Ni and P in the R.E.2Ni12P5 compounds. Crystal structure of the ternary phosphate Ce2Ni12P5 has been refined using X-ray powder diffraction pattern of the single phase sample with the same nominal composition, and the isotopic structure as for earlier known La2Ni12P5-type has been proved: space group P21/m, formula units Z = 2, lattice parameters are a = 1.07809(2) nm, b = 0.36869(1) nm, c = 1.31490(3) nm, b = 107.776(4), residual R-values are RI = 0.0681, RP = 0.0442 , RwP = 0.0603. The theoretical calculations have been carried out by means of the ab initio fully-relativistic spinpolarized Dirac linear muffin-tin orbital method. The calculations show good agreement with the experimental measurements. R.E.LIII - absorption spectra in ternary R.E.2Ni12P5 compounds were obtained at 78K and 300K using a tube spectrometer equipped with an RKD-01 co-ordinate detector. The mixed valence state of Ce and Eu was obtained in the Ce2Ni12P5 and Eu2Ni12P5 compounds.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018",
title = "Crystal structure and X-Ray spectroscopic properties of R.E.2Ni12P5 compounds",
pages = "109-109"
}

High-energy spectroscopy of YbM2P2 compounds

Shcherba, Ivan D.; Noga, Henrik; Antonov, Viktor; Uskoković, Dragan; Kovalska, Maria V.; Jatcyk, Bohdan M.

(Belgrade : Materials Research Society of Serbia, 2017)

TY  - CONF
AU  - Shcherba, Ivan D.
AU  - Noga, Henrik
AU  - Antonov, Viktor
AU  - Uskoković, Dragan
AU  - Kovalska, Maria V.
AU  - Jatcyk, Bohdan M.
PY  - 2017
UR  - http://dais.sanu.ac.rs/123456789/15446
AB  - We have studied experimentally and theoretically the electronic structure and x-ray absorption spectrum at the Yb L3-edge and x-ray emission spectra of M and P at the K- and L2,3 -edges in the mixed valence compound YbM2P2 (with ThCr2Si2 type crystal structure), where M=Fe, Co, Ni. The theoretical calculations have been carried out by means of the ab initio fully-relativistic spin-polarized Dirac linear muffin-tin orbital method. The calculations show good agreement with the experimental measurements. The LSDA +U with Ueff > 8.8 eV produces two independent self-consistent solutions YbNi2P2 with divalent Yb2+ and trivalent Yb3+ ions. For the divalent Yb ion we found a non-magnetic solution with fourteen 4f electron bands completely occupied and situated far below the Fermi level. For trivalent Yb3+ solution thirteen 4f electron bands are situated well below the Fermi level. The hole 4f level for the Yb3+ solution the completely empty and situated sufficiently far from the Fermi level, therefore YbNi2P2 belong to the in homogeneously mixed-valence compounds. The calculated total magnetic moment for the Yb3+ solution moment is dominated by the 4f compounds, the spin Ms and orbital Ml moments are 0.365 μB, and 1.135 μB, respectively. The spin and orbital moments at the Ni and P sites are very small: Ms Ni= - 0.0028 B, MsP=-0.0017 μB, MlNi =-0.0019 μB and MlP =0.0004 μB. Both the trivalent and the divalent Yb ions in are reflected in the experimentally measured Yb L3 x-ray absorption spectrum simultaneously. We found that the best agreement between the experimental spectrum and sum of the theoretically calculated Yb2+ and Yb3+ spectra is achieved with 73% ytterbium ions 2+ state and 27% ions in 3+ state. We found that the effect of the electronic quadrupole E2 transitions as well as the core-hole effect in the final states has minor influence on the intensity and the shape of the Ni and P K and L2.3 emission spectra as well as on the Yb L3 absorption spectrum. We would like to point out that the LSDA +U method which combines LSDA with a basically static, i.e. Hartree-Fock-like, mean –field approximation for a multi-band Anderson lattice model does not contain true many body physics. However, this method can be considered as the first step towards a better description of strongly correlated electron systems. The LSDA +U method provides the correct energy position of 4f energy bands and gives a reasonable description of the XAS and XES properties in YbNi2P2. However, the energy band structure for finite temperatures and the presumed Kondo lattice and mixed valence behavior in YbNi2P2 clearly requires a treatment that goes beyond a static mean-field approximation and includes dynamical effects, e.g., the frequency dependence of the sell-energy.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Nineteenth Annual Conference YUCOMAT 2017, Herceg Novi, September 4-8, 2017
T1  - High-energy spectroscopy of YbM2P2 compounds
SP  - 82
EP  - 82
ER  - 
@conference{
author = "Shcherba, Ivan D. and Noga, Henrik and Antonov, Viktor and Uskoković, Dragan and Kovalska, Maria V. and Jatcyk, Bohdan M.",
year = "2017",
url = "http://dais.sanu.ac.rs/123456789/15446",
abstract = "We have studied experimentally and theoretically the electronic structure and x-ray absorption spectrum at the Yb L3-edge and x-ray emission spectra of M and P at the K- and L2,3 -edges in the mixed valence compound YbM2P2 (with ThCr2Si2 type crystal structure), where M=Fe, Co, Ni. The theoretical calculations have been carried out by means of the ab initio fully-relativistic spin-polarized Dirac linear muffin-tin orbital method. The calculations show good agreement with the experimental measurements. The LSDA +U with Ueff > 8.8 eV produces two independent self-consistent solutions YbNi2P2 with divalent Yb2+ and trivalent Yb3+ ions. For the divalent Yb ion we found a non-magnetic solution with fourteen 4f electron bands completely occupied and situated far below the Fermi level. For trivalent Yb3+ solution thirteen 4f electron bands are situated well below the Fermi level. The hole 4f level for the Yb3+ solution the completely empty and situated sufficiently far from the Fermi level, therefore YbNi2P2 belong to the in homogeneously mixed-valence compounds. The calculated total magnetic moment for the Yb3+ solution moment is dominated by the 4f compounds, the spin Ms and orbital Ml moments are 0.365 μB, and 1.135 μB, respectively. The spin and orbital moments at the Ni and P sites are very small: Ms Ni= - 0.0028 B, MsP=-0.0017 μB, MlNi =-0.0019 μB and MlP =0.0004 μB. Both the trivalent and the divalent Yb ions in are reflected in the experimentally measured Yb L3 x-ray absorption spectrum simultaneously. We found that the best agreement between the experimental spectrum and sum of the theoretically calculated Yb2+ and Yb3+ spectra is achieved with 73% ytterbium ions 2+ state and 27% ions in 3+ state. We found that the effect of the electronic quadrupole E2 transitions as well as the core-hole effect in the final states has minor influence on the intensity and the shape of the Ni and P K and L2.3 emission spectra as well as on the Yb L3 absorption spectrum. We would like to point out that the LSDA +U method which combines LSDA with a basically static, i.e. Hartree-Fock-like, mean –field approximation for a multi-band Anderson lattice model does not contain true many body physics. However, this method can be considered as the first step towards a better description of strongly correlated electron systems. The LSDA +U method provides the correct energy position of 4f energy bands and gives a reasonable description of the XAS and XES properties in YbNi2P2. However, the energy band structure for finite temperatures and the presumed Kondo lattice and mixed valence behavior in YbNi2P2 clearly requires a treatment that goes beyond a static mean-field approximation and includes dynamical effects, e.g., the frequency dependence of the sell-energy.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Nineteenth Annual Conference YUCOMAT 2017, Herceg Novi, September 4-8, 2017",
title = "High-energy spectroscopy of YbM2P2 compounds",
pages = "82-82"
}