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Kovalska, Maria V.

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  • Kovalska, Maria V. (3)
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Author's Bibliography

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"
}
Shcherba, I. D., Noga, H., Antonov, V., Uskoković, D., Kovalska, M. V.,& Jatcyk, B. M. (2017). High-energy spectroscopy of YbM2P2 compounds.
Programme and The Book of Abstracts / Nineteenth Annual Conference YUCOMAT 2017, Herceg Novi, September 4-8, 2017Belgrade : Materials Research Society of Serbia., null, 82-82. 
Shcherba ID, Noga H, Antonov V, Uskoković D, Kovalska MV, Jatcyk BM. High-energy spectroscopy of YbM2P2 compounds. Programme and The Book of Abstracts / Nineteenth Annual Conference YUCOMAT 2017, Herceg Novi, September 4-8, 2017. 2017;:82-82

Electronic structure and X-ray spectroscopic properties of YbNi2P2

Shcherba, Ivan D.; Bekenov, L. V.; Antonov, V. N.; Noga, Henrik; Uskoković, Dragan; Zhak, Olga; Kovalska, Maria V.

(Elsevier, 2016)

TY  - JOUR
AU  - Shcherba, Ivan D.
AU  - Bekenov, L. V.
AU  - Antonov, V. N.
AU  - Noga, Henrik
AU  - Uskoković, Dragan
AU  - Zhak, Olga
AU  - Kovalska, Maria V.
PY  - 2016
UR  - http://dais.sanu.ac.rs/123456789/16005
AB  - X-ray absorption spectrum at the Yb L3 edge and X-ray emission spectra of Ni and P at the K and L2,3 edges have been studied experimentally and theoretically in the mixed valent compound YbNi2P2 with ThCr2Si2 type crystal structure. The electronic structure of YbNi2P2 is investigated using the fully relativistic Dirac linear muffin-tin orbital (LMTO) band-structure method. The effect of the spin–orbit (SO) interaction and Coulomb repulsion U on the electronic structure of YbNi2P2 is examined in the frame of the LSDA + SO + U method. The core-hole effect in the final states as well as the effect of the electric quadrupole E2 transitions have been investigated. A good agreement between the theory and the experiment was found. Both the trivalent and the divalent Yb ions in YbNi2P2 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 in 2+ state and 27% ions in 3+ state.
PB  - Elsevier
T2  - Journal of Electron Spectroscopy and Related Phenomena
T1  - Electronic structure and X-ray spectroscopic properties of YbNi2P2
SP  - 5
EP  - 10
VL  - 212
DO  - 10.1016/j.elspec.2016.07.002
ER  - 
@article{
author = "Shcherba, Ivan D. and Bekenov, L. V. and Antonov, V. N. and Noga, Henrik and Uskoković, Dragan and Zhak, Olga and Kovalska, Maria V.",
year = "2016",
url = "http://dais.sanu.ac.rs/123456789/16005",
abstract = "X-ray absorption spectrum at the Yb L3 edge and X-ray emission spectra of Ni and P at the K and L2,3 edges have been studied experimentally and theoretically in the mixed valent compound YbNi2P2 with ThCr2Si2 type crystal structure. The electronic structure of YbNi2P2 is investigated using the fully relativistic Dirac linear muffin-tin orbital (LMTO) band-structure method. The effect of the spin–orbit (SO) interaction and Coulomb repulsion U on the electronic structure of YbNi2P2 is examined in the frame of the LSDA + SO + U method. The core-hole effect in the final states as well as the effect of the electric quadrupole E2 transitions have been investigated. A good agreement between the theory and the experiment was found. Both the trivalent and the divalent Yb ions in YbNi2P2 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 in 2+ state and 27% ions in 3+ state.",
publisher = "Elsevier",
journal = "Journal of Electron Spectroscopy and Related Phenomena",
title = "Electronic structure and X-ray spectroscopic properties of YbNi2P2",
pages = "5-10",
volume = "212",
doi = "10.1016/j.elspec.2016.07.002"
}
Shcherba, I. D., Bekenov, L. V., Antonov, V. N., Noga, H., Uskoković, D., Zhak, O.,& Kovalska, M. V. (2016). Electronic structure and X-ray spectroscopic properties of YbNi2P2.
Journal of Electron Spectroscopy and Related PhenomenaElsevier., 212, 5-10. 
https://doi.org/10.1016/j.elspec.2016.07.002
Shcherba ID, Bekenov LV, Antonov VN, Noga H, Uskoković D, Zhak O, Kovalska MV. Electronic structure and X-ray spectroscopic properties of YbNi2P2. Journal of Electron Spectroscopy and Related Phenomena. 2016;212:5-10
2
3
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Valence State Ce(Yb), Electron Structure and Physical Properties of New Ternary Intermetallic Compounds

Scherba, Ivan; Uskoković, Dragan; Kovalska, Maria V.

(Belgrade : Materials Research Society of Serbia, 2015)

TY  - CONF
AU  - Scherba, Ivan
AU  - Uskoković, Dragan
AU  - Kovalska, Maria V.
PY  - 2015
UR  - http://dais.sanu.ac.rs/123456789/830
AB  - High-energy spectroscopy (XES, XAS and XPS) has been used to study the electron structure of the investigated new ternary intermetallic compounds. In recent years there has been a continually increasing interest in investigation of ternary compounds with crystallize in the YNi9Si2, CeGa2Al2, Yb2Fe4Si9, ThMn12 and AlB2, which have a large variety of ground state properties. LIII -absorption spectra Ce(Yb) in ternary compounds were obtained at 80K and 300K using a tube spectrometer. The mixed valence state of Ce(Yb) was obtained in the investigation compounds. The measurements were carried out both with classical methods as well with the Mossbauer effect in order to establish parameters of the hyperfine interactions (only for confirm Fe atoms compounds). The calculations of electron energy bands E(k) and partial DOS for compounds new R.E.M2X2 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 / Seventeenth Annual Conference YUCOMAT 2015, Herceg Novi, August 31– September 4, 2015
T1  - Valence State Ce(Yb), Electron Structure and Physical Properties of New Ternary Intermetallic Compounds
SP  - 66
EP  - 66
ER  - 
@conference{
author = "Scherba, Ivan and Uskoković, Dragan and Kovalska, Maria V.",
year = "2015",
url = "http://dais.sanu.ac.rs/123456789/830",
abstract = "High-energy spectroscopy (XES, XAS and XPS) has been used to study the electron structure of the investigated new ternary intermetallic compounds. In recent years there has been a continually increasing interest in investigation of ternary compounds with crystallize in the YNi9Si2, CeGa2Al2, Yb2Fe4Si9, ThMn12 and AlB2, which have a large variety of ground state properties. LIII -absorption spectra Ce(Yb) in ternary compounds were obtained at 80K and 300K using a tube spectrometer. The mixed valence state of Ce(Yb) was obtained in the investigation compounds. The measurements were carried out both with classical methods as well with the Mossbauer effect in order to establish parameters of the hyperfine interactions (only for confirm Fe atoms compounds). The calculations of electron energy bands E(k) and partial DOS for compounds new R.E.M2X2 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 / Seventeenth Annual Conference YUCOMAT 2015, Herceg Novi, August 31– September 4, 2015",
title = "Valence State Ce(Yb), Electron Structure and Physical Properties of New Ternary Intermetallic Compounds",
pages = "66-66"
}
Scherba, I., Uskoković, D.,& Kovalska, M. V. (2015). Valence State Ce(Yb), Electron Structure and Physical Properties of New Ternary Intermetallic Compounds.
Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 2015, Herceg Novi, August 31– September 4, 2015Belgrade : Materials Research Society of Serbia., null, 66-66. 
Scherba I, Uskoković D, Kovalska MV. Valence State Ce(Yb), Electron Structure and Physical Properties of New Ternary Intermetallic Compounds. Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 2015, Herceg Novi, August 31– September 4, 2015. 2015;:66-66