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Wyszukujesz frazę "71.70.-d" wg kryterium: Temat


Tytuł:
2D Angular Correlation of Annihilation Radiation: Current Trends and Future Possibilities
Autorzy:
West, R. N.
Powiązania:
https://bibliotekanauki.pl/articles/1933550.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.28.+d
71.25.Ηc
78.70.Bj
Opis:
Recent improvements in two-dimensional angular correlation measurement and analysis techniques have greatly increased the power of the method to image the Fermi surfaces of electronically complex systems. That, and the further and dramatic improvement that must result when the present radioisotope positron sources are replaced by intense monoenergetic positron beams are discussed and illustrated.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 249-256
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Band Edge Energies Pinning in Magnetic Field in Semimagnetic $Cd_{0.7}Mn_{0.3}Te$
Autorzy:
Barauskaitė, L.
Brazis, R.
Ivanov, V.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1492778.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
75.50.Pp
71.70.-d
Opis:
Results of $Cd_{0.7}Mn_{0.3}Te$ magneto-photoluminescence investigations are analyzed. Photoluminescence was measured in a Voigt geometry at the temperature of 1.6 K. Two models describing radiative transition energy are compared with the experimental results of $Cd_{0.7}Mn_{0.3}Te$ luminescence. The energy of recombination transition, employing the complete form of band states splitting description (term due to the Landau splitting included), shows deviation from experiment at B > 2 T. Two possible reasons of discrepancies from the experiment - exchange interaction constants dependence on magnetic field or band edge energies pinning in magnetic field - are discussed. Band edge energies pinning in magnetic field is related to the hybridization of Mn 3 $d^{5}$ levels with the band states of the host. We determine the corrected values of exchange interaction constants $(N_0 α -N_0 β//3)$ at magnetic fields B < 5 T.
Źródło:
Acta Physica Polonica A; 2011, 120, 6; 1056-1060
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal-Field Origin of the Giant Magnetocrystalline Anisotropy of PrRu$\text{}_{2}$Si$\text{}_{2}$
Autorzy:
Michalski, R.
Ropka, Z.
Radwański, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/2013368.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.-d
71.20.Eh
Opis:
PrRu$\text{}_{2}$Si$\text{}_{2}$ shows ferromagnetism below 14 K with the ordered moment of 2.7μ$\text{}_{B}$. It exhibits an enormous magnetic anisotropy at 4.2 K with the anisotropy field of about 400 T. We have attrributed the magnetism of PrRu$\text{}_{2}$Si$\text{}_{2}$ to the Pr$\text{}^{3+}$ ions. Thus we performed calculations of the fine electronic structure of the Pr$\text{}^{3+}$ ion in the tetragonal symmetry, relevant to PrRu$\text{}_{2}$Si$\text{}_{2}$, taking into account crystal-field and inter-site exchange interactions. Our calculations reproduce well the zero-temperature moment, the single-crystalline magnetization curves, and giant anisotropy field as 400 T. The magnetocrystalline-anisotropy energy K$\text{}_{1}$ of 59 J/cm$\text{}^{3}$ is the largest known anisotropy - the anisotropy energy of the Nd$\text{}_{2}$Fe$\text{}_{14}$B supermagnet amounts to 12.5 J/cm$\text{}^{3}$ only. Unfortunately, this giant anisotropy is confined to low temperatures only which prohibits its technical applications in the permanent-magnet industry.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 767-770
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Double Reflection of Electron Spin in Semiconductors
Autorzy:
Dargys, A.
Powiązania:
https://bibliotekanauki.pl/articles/1505522.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.75.-d
72.25.Dc
71.70.Ej
03.65.Fd
Opis:
Reflection of spin-polarized electron from a potential barrier in bulk semiconductor in the presence of spin-orbit interaction is considered. The spin-orbit interaction brings about double electron reflection at oblique incidence of electronic beam onto the barrier. The competition between the Rashba and Dresselhaus spin-orbit mechanisms during double reflection is discussed. The problem was solved within the Clifford algebra framework, which allows one to describe the spin in a real Euclidean $ℰ_3$ space rather than in an abstract Hilbert space.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 161-163
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Zinc-Blende Zn$\text{}_{0.5}$Co$\text{}_{0.5}$Se: Theoretical Study
Autorzy:
Hołda, A.
Markowski, R.
Dębowska, D.
Kisiel, A.
Zimnal-Starnawska, M.
Piacentini, M.
Zema, N.
Lama, F.
Powiązania:
https://bibliotekanauki.pl/articles/1950806.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.20.Cf
71.70.-d
Opis:
In this paper we present partial densities of states for spin-polarized antiferromagnetic phase of Zn$\text{}_{0.5}$Co$\text{}_{0.5}$Se as well as schematic layouts of the bands, obtained using the ab initio self-consistent semi-relativistic linear muffin tin orbital method. We also present, from theoretical point of view, the analysis of influence of the transition metal cobalt on the electronic structure of a pure ZnSe.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 817-820
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Zinc-Blende Zn$\text{}_{0.5}$V$\text{}_{0.5}$Se: Theoretical Study
Autorzy:
Markowski, R.
Hołda, A.
Dębowska, D.
Kisiel, A.
Zimnal-Starnawska, M.
Piacentini, M.
Zema, N.
Lama, F.
Powiązania:
https://bibliotekanauki.pl/articles/1934068.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.70.-d
71.20.Cf
Opis:
In this paper we present a comprehensive study of electronic structure of Zn$\text{}_{0.5}$V$\text{}_{0.5}$Se from the theoretical point of view. Partial and total density of states for spin-polarized antiferromagnetic phase of Zn$\text{}_{0.5}$V$\text{}_{0.5}$Se as well as schematic layouts of the bands have been obtained using the ab initio self-consistent semirelativistic linear muffin-tin orbital method.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 1023-1027
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Charge Model for $Fe^{3+}:LiAl_{5}O_{8}$
Autorzy:
Vaida, M.
Avram, C.
Powiązania:
https://bibliotekanauki.pl/articles/1791224.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
78.20.Bh
34.20.Cf
71.70.-d
Opis:
The aim of this paper is the theoretical investigation of $Fe^{3+}$ doped in the ordered phase of $LiAl_{5}O_8$. We used the shell model and pair potential approximation to optimize the geometric structure of $LiAl_{5}O_{8}$. This approach enables the modeling of the crystal field parameters of $LiAl_{5}O_8$ and then calculates the energy levels scheme of $Fe^{3+}$ ions doped in tetrahedral sites in the title crystal. Consistent crystal field analysis and the energy level splittings for $LiAl_{5}O_{8}$ doped with $Fe^{3+}$ ions was performed in the frame of the exchange charge model of crystal field. The comparison of the theoretically obtained results for energy levels with the experimental data, yields satisfactory agreement and confirms the validity of the exchange charge model.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 541-543
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Interaction as a Source of Real Space Pairing in High Temperature Superconductors and Heavy Fermions: a Brief Overview
Autorzy:
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1860823.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.28.+d
75.10.Lp
74.70.Vy
Opis:
We characterize the principal difference between the pairing induced by the kinetic exchange interactions for the Fermi-liquid and spin-liquid phases. In the case of hybridized electrons the Kondo-exchange induced pairing is invoked, whereas for a single narrow-band case kinetic exchange is responsible for the spin singlet pairing. The former interaction is applied to heavy-fermion systems, whereas the latter is employed to the high temperature superconductors. The current situation concerning the applicability of our theoretical models is briefly and critically assessed.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 39-52
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Capacity Studies of $NdNi_4Si$ Compound
Autorzy:
Falkowski, M.
Reiffers, M.
Zapotoková, M.
Kowalczyk, A.
Toliński, T.
Gažo, E.
Powiązania:
https://bibliotekanauki.pl/articles/1810401.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.De
65.40.gd
71.20.Eh
71.70.-d
Opis:
The study of the heat capacity of the intermetallic compound $NdNi_{4}Si$ including the effect of the magnetic field is reported. This compound crystallizes in the hexagonal $CaCu_5$-type structure, space group P6/mmm. $NdNi_{4}Si$ is ferromagnetic with $T_C$ = 8 K and the saturation magnetic moment of 1.5 $μ_{B}$/f.u. at 4.2 K (in H = 9 T). The heat capacity was analyzed considering the electronic contribution, the Schottky anomaly, and the lattice contributions in the frames of the Debye model. The scheme of the energy levels created by the crystal electric field split is determined from the Schottky contribution to the specific heat. $NdNi_{4}Si$ was characterized by the electronic heat capacity coefficient γ = 85 mJ/(mol $K^2$) and the Debye temperature $Θp_D$ = 325 K.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 126-128
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hot Carrier Effects in Optically Detected Cyclotron Resonance Studies of III-V Semiconductors
Autorzy:
Karpińska, K.
Dedulewicz, S.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1920978.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.+z
72.70.+m
76.90.+d
Opis:
The mechanisms of irregular photoluminescence intensity oscillations, as observed in optically detected cyclotron resonance experiments, are discussed. Two possible scenarios are analyzed, both requiring impact ionization of the center(s) by electric field accelerated free carriers. The first assumes coexistence of dielectric and energy relaxation processes. The second assumes a subsequent impact ionization of two different centers.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 623-626
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact Ionization Driven Chaotic Photoluminescence Oscillations in Ga$\text{}_{0.47}$In$\text{}_{0.53}$As
Autorzy:
Godlewski, M.
Fronc, K.
Gajewska, M.
Chen, W.M.
Monemar, B.
Powiązania:
https://bibliotekanauki.pl/articles/1888119.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.+z
72.70.+m
76.90.+d
Opis:
A new application of the Optically Detected Cyclotron Resonance (ODCR) is presented. We report impact ionization studies of bound exciton: (BE) and shallow donor related recombination processes in Ga$\text{}_{0.47}$In$\text{}_{0.53}$As. An appearance of chaotic oscillations in photoluminescence (PL) intensity is observed under condition of impact ionization of deeper donors.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 271-274
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Indications for Diamagnetic Shift in the Ground State of Boron in Silicon
Autorzy:
Stöhr, M.
Chroboczek, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/1891427.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Ht
71.70.-d
72.20.-i
Opis:
Indications for the observation of the diamagnetic shrinkage of the boron acceptor wave function (WF) in Si are reported. Uniaxial stress (X) was used to split the ground state (GS) of the boron acceptor into two energy levels with spatially complementary WF. The magnetic field selectively induces a shrinking of one of the two WF, depending on whether it is applied parallel or perpendicular to the X axis. As a result, the hopping transitions between lower and higher energy levels are redistributed, leading to significant changes in the activation energy ε$\text{}_{3}$. This effect was borne out by experiment.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 465-468
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Mixed Valence State of $Sm_{1-x}B_{6}$ and $Sm_{1-x}La_{x}B_{6}$ by XANES
Autorzy:
Gabáni, S.
Flachbart, K.
Bednarčík, J.
Welter, E.
Filipov, V.
Shitsevalova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1371509.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
71.28.+d
71.27.+a
Opis:
We investigated the valence states of samarium ions in Sm deficient $Sm_{1-x}B_{6}$ (x=0.03, 0.05, 0.08, 0.1 and 0.2) sintered samples, in single crystalline solid solutions $Sm_{1-x}La_{x}B_{6}$ (x=0.16, 0.28, 0.4, 0.55 and 0.7) as well as in a $SmB_{6}$ single crystal by X-ray absorption near edge structure (XANES) between 4.2 and 300 K. It was shown that the mixed valence state $v_{Sm}$ of Sm-ions ($v_{Sm}$ ≈ 2.51 for $SmB_{6}$ at 4.2 K) in deficient samples is changed but maintained up to a concentration of 20% of vacancies and up to a concentration of 70% in samples doped with trivalent La-ions, and that in both cases it increases with temperature. On the other hand, the value of $v_{Sm}$ increases with increasing vacancy level, whereas it decreases with increasing $La^{3+}$ substitution. The obtained dependences of Sm-valence in $SmB_{6}$ on vacancy as well as on $La^{3+}$ ion concentration are in good agreement with susceptibility measurements and exact numerical calculation of the spinless Falicov-Kimball model in two dimensions.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 338-339
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Iron Impurity Related Optical Transitions in HgSe:Fe
Autorzy:
Szuszkiewicz, W.
Julien, C.
Balkanski, M.
Arciszewska, M.
Witkowska, B.
Mycielski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1891323.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Fr
71.70.-d
78.50.Ge
Opis:
Fe$\text{}^{2+}$ crystal field transitions and the heavy hole valence band to the Fe level transitions (e + Fe$\text{}^{3+}$ → Fe$\text{}^{2+}$) have been observed and discussed for HgSe doped with iron.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 437-440
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Specific Heat of Pb$\text{}_{1-x}$Eu$\text{}_{x}$Te
Autorzy:
Górska, M.
Łusakowski, A.
Jędrzejczak, A.
Gołacki, Z.
Anderson, J. R.
Balci, H.
Powiązania:
https://bibliotekanauki.pl/articles/2038143.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.-d
75.40.Cx
Opis:
The temperature dependence of the magnetic specific heat was studied experimentally and theoretically in the semimagnetic semiconductor Pb$\text{}_{1-x}$Eu$\text{}_{x}$Te for x=0.027 and x=0.073, over the temperature range from 0.5 K to 15 K, in magnetic fields up to 2 T. In zero magnetic field at about 2 K there was a broad maximum in the magnetic specific heat, which was much higher than that predicted by the model of superexchange interaction between nearest neighbors; the maximum values increased with magnetic field. The experimental data were analyzed in the framework of a model which takes into account the spin splitting of the ground state of a single Eu2+ ion in the presence of local lattice distortions in the Pb$\text{}_{1-x}$Eu$\text{}_{x}$Te mixed crystal. The model describes well the experimental data, especially for lower x-values, where the contribution from singlets dominates.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 631-636
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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