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Tytuł:
Electronic Structure and Transport Properties of UFe$\text{}_{2}$ System
Autorzy:
Szlaferek, A.
Szajek, A.
Baszyński, J.
Smardz, L.
Kowalczyk, A.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/2013662.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.La
71.20.Lp
72.15.Eb
Opis:
The electronic structure of the UFe$\text{}_{2}$ compound was studied by X-ray photoemission spectroscopy and ab initio self-consistent tight binding muffin tin orbital method. This compound crystallizes in a cubic Laves phase. The calculated valence band spectrum is characterized by two peaks due to U(5f) and Fe(3d) states. We have found a good agreement between the experimental valence band spectrum and theoretical ab initio calculations. The carrier concentration estimated from the Hall effect amounts to ≈10$\text{}^{22}$ cm$\text{}^{-3}$.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 815-818
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Ternary Antimonides YbPdSb
Autorzy:
Hermanowicz, M.
Jezierski, A.
Kaczkowski, J.
Kaczorowski, D.
Powiązania:
https://bibliotekanauki.pl/articles/1810476.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.15.Ap
71.15.Mb
71.20.Eh
71.20.Lp
Opis:
In this paper we present the electronic structure and magnetic properties of YbPdSb in low-temperature MgAsAg-type structure and high-temperature TiNiSi-type structure. The calculations were performed by ab initio full-relativistic full potential local orbital method within the local spin density approximation. Ab initio calculations showed the metallic character of YbPdSb compound in both structures. The density of states at the Fermi level is greater in high-temperature than in low-temperature structure.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 226-228
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Hydrogenation on the Electronic Structure of HoNiSn - Ab Initio Calculations
Autorzy:
Jezierski, A.
Szajek, A.
Jurczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1537053.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.15.Ap
71.15.Mb
71.20.Eh
71.20.Lp
Opis:
The electronic and magnetic properties of HoNiSn alloy are studied by ab initio full relativistic full potential local orbital method within the local density approximation. The electronic structures are reported for two crystallographic structures: orthorhombic TiNiSi type and the hexagonal ZrNiAl-type structure. We also study the influence of hydrogenation on the electronic structure of $HoNiSnH_{0.66}$. Ab initio calculations have shown that in the both type of structures the Fermi level is located at the 4f peak of Ho, however we observed the modification of 3d peaks from nickel atoms below the Fermi energy. The hydrogenation leads to increase of the density of states at the Fermi level.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 346-349
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Ternary Antimonides GdNiSb
Autorzy:
Wei, X.
Hu, X.
Dai, Y.
Lei, T.
Chu, S.
Deng, J.
Powiązania:
https://bibliotekanauki.pl/articles/1505358.pdf
Data publikacji:
2011-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.15.Ap
71.15.Mb
71.20.Eh
71.20.Lp
Opis:
In the paper density functional theory method was applied to explore the electronic and magnetic properties of the GdNiSb in low-temperature phase with cubic MgAsAg-type structure and in the high-temperature phase. The calculations were performed by first principles full-relativistic full potential local orbital method within the local spin density approximation. The calculations results show the metallic character of GdNiSb compound in the high-temperature phase with hexagonal $AlB_2$-type structure. For the low-temperature phase of the cubic GdNiSb system, they indicate a semiconducting behavior. The density of states below the Fermi level is greater in high-temperature phase than in low-temperature one, the calculated magnetic moment is in good agreement with an available experimental value.
Źródło:
Acta Physica Polonica A; 2011, 119, 3; 405-407
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lanthanide Contraction in $RENi_5$ (RE~=~La, Ce, Nd, Sm, Eu, Gd, Tb,~Yb) Compounds Studied with Band Structure Calculations
Autorzy:
Goraus, J.
Maślankiewicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1426989.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.Mb
71.20.Lp
71.27.+a
31.15.E-
Opis:
Full potential linearized augmented plane wave band structure calculations were performed for hexagonal $RENi_5$ (RE = rare earth) compounds in order to investigate reproducibility of lanthanide contraction by ab initio studies. The a and c parameters were optimised using a paraboloid fit, starting from the same initial values for all compounds studied. The trend in lattice parameters across the RE series obtained from the calculations was found to be in general agreement with experimental data. A comparison of results obtained by generalized gradient approximation and generalized gradient approximation with additional Coulomb correlations calculations is presented for several double counting schemes.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1076-1078
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Foundation for the Hume-Rothery Electron Concentration Rule for Structurally Complex Alloys
Autorzy:
Mizutani, U.
Sato, H.
Inukai, M.
Zijlstra, E.
Powiązania:
https://bibliotekanauki.pl/articles/1382955.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Be
71.20.Lp
71.15.Mb
Opis:
An electron concentration parameter, expressed as the number of itinerant electrons per number of atoms N in a structural unit cell of an alloy, e/uc, is a useful parameter that can be used in interpreting the origin of a band structure pseudogap often evident at the Fermi level for structurally complex metallic alloy phases. It can be expressed in terms of the interference condition e/uc=$π/3[|G|_{c}^2]^{3/2}$, where $|G|_{c}^2$ is the square of the critical reciprocal lattice vector associated with the specific set of lattice planes interfering with electrons at the Fermi level. This parameter is similar to the well-known Hume-Rothery electron concentration parameter e/a, which represents the number of electrons per atom and is linked with e/uc through the relation e/uc = N(e/a). We have demonstrated that certain complex metallic alloy structures appear to be stable at or near certain values of e/a. We show that the e/a=1.60 rule holds for the sub-group of gamma-brasses with space group I4̅3m and Pearson symbol cI52, the e/a=4.34 rule for skutterudite compounds with Im3̅ and cI32, the e/a=2.74 rule for $Al_6TM$ (TM = Mn, Tc, Re, Fe, and Ru) compounds with Cmcm and oC28, the e/a=1.62 rule for the sub-group of the Heusler compounds with Fm3̅m and cF16, and the e/a=2.09 rule for the sub-group of Zintl compounds $MX_1$ (M = Li and Na, $X_1$ = Al, Ga, In, and Tl) with Fd3̅m and cF32. The e/a rule holds in sub-groups of isostructural compounds, regardless of the degree of orbital hybridizations and the polarity involved.
Źródło:
Acta Physica Polonica A; 2014, 126, 2; 531-534
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on mechanical properties of Mn₃Sb intermetallic compound
Autorzy:
Boubaker, O.
Said, B.
Powiązania:
https://bibliotekanauki.pl/articles/1068548.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
62.20.-x
31.15.A-
Opis:
In this work, ab initio calculation has been performed to investigate the structural, elastic and mechanical properties of Mn₃Sb intermetallic compound, based on density functional theory plane-wave pseudo potential method within local density approximation and generalized gradient approximation. The calculated structural parameter in both approximations of Mn₃Sb compound is consistent with the experimental data. The elastic constants were determined from a linear fit of the calculated stress-strain function according to the Hooke law. From the elastic constants, the bulk modulus B, shear modulus G, the Young modulus E, the Poisson ratio σ , anisotropy factor A and the ratio B/G for Mn₃Sb compound are obtained. This is the first quantitative theoretical prediction of these properties.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 33-35
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Local Environment on the Magnetic Properties of the Ordered Fe$\text{}_{1-x}$Al$\text{}_{x}$ Alloy
Autorzy:
Deniszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/2013232.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.La
71.15.Fv
71.20.Lp
75.50.Bb
75.30.-m
Opis:
The electronic and magnetic properties of the ordered binary Fe$\text{}_{1-x}$Al$\text{}_{x}$ alloy with the B2 crystal structure were calculated for Al concentrations x=0.1875-0.5 using the supercell structure. The calculations showed that for increasing Al contents the average magnetization of Fe$\text{}_{1-x}$Al$\text{}_{x}$ falls down rapidly. Upon lowering the unit cell volume, almost all configurations of compositions with x ≥ 0.25 show the abrupt change of magnetic state from the high moment magnetic state to the low moment magnetic state with the moment reduction 0.6-0.8 μ$\text{}_{B}$ per atom. The configurations were found for which the low moment magnetic state solutions with the antiferromagnetic alignment of magnetic moments of Fe atoms at antisite positions are stable.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 583-586
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyperfine Interactions of $\text{}^{57}Fe$ in #Pt_3Fe# - Ab Initio and Mössbauer Effect Studies
Autorzy:
Deniszczyk, J.
Satuła, D.
Waliszewski, J.
Rećko, K.
Olszewski, W.
Parzych, G.
Szymański, K.
Powiązania:
https://bibliotekanauki.pl/articles/1810456.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.Ap
71.15.Nc
71.20.-b
71.20.Be
71.20.Lp
75.50.Bb
76.80.+y
Opis:
The Mössbauer effect and ab initio investigations of an electric field gradient at $\text{}^{57}Fe$ nuclei in $Pt_3Fe$ compound are presented. It is shown that nonzero $\text{}^{57}Fe$ electric field gradient exists in the cubic $Pt_3Fe$. Ab initio study of $Pt_3Fe$ in antiferromagnetic state confirms the presence of electric field gradient at $\text{}^{57}Fe$ nuclei. Lattice, local valence electron (3d, 4p) and weakly bound 3p core electron contributions to electric field gradient are separated out and discussed in the context of the electronic structure changes upon the antiferromagnetic phase transition.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 197-199
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Order on the Structural and Magnetic Properties of Fe-X (X=Al, Si) Alloys with B2 Structure
Autorzy:
Deniszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/2014406.pdf
Data publikacji:
2000-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
71.15.La
75.50.Bb
75.30.-m
71.15.Fv
Opis:
Previous ab initio super-cell calculations of the magnetic properties of the ordered Fe$\text{}_{1-x}$Al$\text{}_{x}$ alloy in the B2 structure are extended to include the disordered state of the alloy and completed with the calculations for ordered and disordered Fe$\text{}_{1-x}$Si$\text{}_{x}$ alloys. The configurations of the Fe atoms in the anti-site (AS) positions of Fe-X super-cell with the antiferromagnetic order were found. The ground state of Fe$\text{}_{1-x}$Al$\text{}_{x}$ with x≃ 0.3 shows the antiferromagnetic order of the Fe-AS magnetic moments. The concentration dependence of the equilibrium lattice parameter and magnetic moment of Fe$\text{}_{1-x}$X$\text{}_{x}$ in the ordered and disordered state differ qualitatively.
Źródło:
Acta Physica Polonica A; 2000, 98, 5; 543-546
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic structure and X-Ray magnetic circular dichroism in Sm-doped Bi₂Se₃
Autorzy:
Antonov, V.
Bekenov, L.
Uba, S.
Ernst, A.
Powiązania:
https://bibliotekanauki.pl/articles/1048353.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Cc
71.20.Lp
71.15.Rf
Opis:
We studied the structural, electronic, and magnetic properties of Sm-doped Bi₂Se₃ using a GGA approximation in a frame of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. The X-ray absorption spectra (XAS) and X-ray magnetic circular dichroism at the Sm M_{4,5} edges were investigated theoretically from first principles. The calculated results are in good agreement with experimental data. The complex fine structure of the Sm M_{4,5} XAS in Sm-doped Bi₂Se₃ was found to be not compatible with a pure Sm³⁺ valency state. The interpretation demands mixed valent states.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 453-455
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic States of $UNi_2$ from Photoemission Spectroscopy
Autorzy:
Zalecki, R.
Kołodziejczyk, A.
Kim-Ngan, N.
Adamska, A.
Kowalczyk, A.
Toliński, T.
Mihalik, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813761.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
79.60.Bm
71.15.Ap
Opis:
We measured the angle-resolved ultraviolet and X-ray photoemission spectra of $UNi_2$ single crystal. The valence band angle-resolved ultraviolet photoemission spectra were compared to the accessible band structure calculations. For $UNi_2$ the lowest binding energy strong emission at about -0.1 eV comes from U 5f states and overlaps with the Fermi edge. A small feature at -0.6 eV was ascribed also to U 5f electrons with more localised character. The higher-energy two-peak structure at about -1.2 eV and -2.1 eV comes from Ni 3d states. X-ray photoemission spectroscopy shows the standard two-line spin-orbit splitting of the Ni 2p states and of the U 4f states. Some hybridisation of the Ni 3d and U 5f state was observed in the spectra. The pronounced satellites to the Ni 2p and 3p states, associated with the on-site Coulomb repulsion and other electron correlation energies, were observed.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 407-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetism and Crystal Field in PrCuAl₃ and NdCuAl₃
Autorzy:
Novák, P.
Diviš, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032630.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.Mb
71.20.Lp
71.70.Ch
Opis:
During the last five years we developed method to calculate crystal field and magnetism of rare-earth ions in solids. The method is fully ab initio with the exception of a single parameter which adjust the position of f states relative to other valence states and it was successfully applied in insulating systems. In this contribution the method is used to explain multiplet splitting and magnetism in PrCuAl₃ and NdCuAl₃ intermetallics. For the Nd compound the agreement between theory and experiment is good, while for the PrCuAl₃ the agreement is less satisfactory which can be due to the more delocalized 4f electrons of Pr³⁺ comparing to Nd³⁺ ion.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 964-966
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic structure, optical and magneto-optical properties and X-Ray magnetic circular dichroism in hybrid heterostructures Sr₂CrReO₆/BaTiO₃
Autorzy:
Antonov, V.
Bekenov, L.
Uba, S.
Bonda, A.
Uba, L.
Powiązania:
https://bibliotekanauki.pl/articles/1048500.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Cc
71.20.Lp
71.15.Rf
Opis:
We report on the electronic structure of hybrid heterostructure combined the ferromagnetic double perovskite Sr₂CrReO₆ (SCRO) and ferroelectric BaTiO₃ (BTO) calculated in the GGA approach using the fully relativistic spin-polarized Dirac LMTO method. The optical and MO properties as well as the X-ray absorption spectra and X-ray magnetic circular dichroism at the Ti, Ba, and Re L_{2,3} edges and O K edges of the SCRO/BTO heterostructures were investigated theoretically from the first principles. It was shown that the calculations reproduce well available experimental spectra and allow to explain the microscopic origin of the SCRO/BTO heterostructures optical, MO and XMCD spectra.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 456-458
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Materials of RMn$\text{}_{2}$Ge$\text{}_{2}$ Type for Thermomagnetic Devices
Autorzy:
Markin, P. E.
Zemlyanskii, S. V.
Baranov, N. V.
Powiązania:
https://bibliotekanauki.pl/articles/1964624.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
72.15.Jf
75.30.Gw
Opis:
The new type of the working media for thermomagnetic devices is proposed: the intermetallic compounds which have large magnetocrystalline anisotropy and exhibit the spontaneous phase transition from the antiferromagnetic (AF) to ferromagnetic (F) state when the temperature increases above the critical value T$\text{}_{t}$. Moreover, the anisotropy in AF state in the fields below the critical AF-F transition field must be much lower than in the F state. In the present paper the Gd$\text{}_{0.6}$Sm$\text{}_{0.4}$Mn$\text{}_{2}$Ge$\text{}_{2}$ compound belonging to the tetragonal RMn$\text{}_{2}$Ge$\text{}_{2}$ system is investigated. This compound has the critical temperature T$\text{}_{t}$ = 280 K. The thermomagnetic cycle can be realized on the AF-F-AF transition near T$\text{}_{t2}$. The interval of the working temperatures can be shifted with the change of the Gd and Sm concentration.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 327-330
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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