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Wyszukujesz frazę "Demchenko, E." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
XANES Studies of Mn K and $L_{3,2}$ Edges in the (Ga,Mn)As Layers Modified, by High Temperature Annealing
Autorzy:
Wolska, A.
Lawniczak-Jablonska, K.
Klepka, M.
Jakieła, R.
Demchenko, I.
Sadowski, J.
Holub-Krappe, E.
Persson, A.
Arvanitis, D.
Powiązania:
https://bibliotekanauki.pl/articles/1812244.pdf
Data publikacji:
2008-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
75.50.Pp
Opis:
$Ga_{1-x}Mn_xAs$ is commonly considered as a promising material for microelectronic applications utilizing the electron spin. One of the ways that allow increasing the Curie temperature above room temperature is to produce second phase inclusions. In this paper $Ga_{1-x}Mn_xAs$ samples containing precipitations of ferromagnetic MnAs are under consideration. We focus on the atomic and electronic structure around the Mn atoms relating to the cluster formation. The changes in the electronic structure of the Mn, Ga and As atoms in the (Ga,Mn)As layers after high temperature annealing were determined by X-ray absorption near edge spectroscopy. The experimental spectra were compared with the predictions of ab initio full multiple scattering theory using the FEFF 8.4 code. The nominal concentration of the Mn atoms in the investigated samples was 6% and 8%. We do not observe changes in the electronic structure of Ga and As introduced by the presence of the Mn atoms. We find, in contrast, considerable changes in the electronic structure around the Mn atoms. Moreover, for the first time it was possible to indicate the preferred interstitial positions of the Mn atoms.
Źródło:
Acta Physica Polonica A; 2008, 114, 2; 357-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(Eu,Gd)Te - MBE Growth and Characterization
Autorzy:
Dziawa, P.
Taliashvili, B.
Domuchowski, W.
Łusakowska, E.
Arciszewska, M.
Demchenko, I.
Dobrowolski, W.
Dybko, K.
Fedorych, O. M.
Nadolny, A. J.
Osinniy, V.
Petrouchyk, A.
Story, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038228.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
81.15.Hi
Opis:
Monocrystalline thin layers of (Eu,Gd)Te, n-type ferromagnetic semiconductor, were grown by molecular beam epitaxy technique on BaF$\text{}_{2}$ (111) substrates. Reflection high-energy electron diffraction, X-ray diffraction, and atomic force microscopy characterization proved epitaxial mode of growth and high crystal quality of the layers. Magnetic susceptibility and magnetic resonance measurements showed that in (Eu,Gd)Te layers ferromagnetic transition takes place at about 13 K. Electrical characterization carried out by the Hall effect and resistivity measurements revealed very high electron concentration of 10$\text{}^{20}$~cm$\text{}^{-3}$ and sharp maximum of resistivity at transition temperature.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 215-221
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-Ray Absorption Studies of Ge Layers Buried in Silicon Crystal
Autorzy:
Demchenko, I. N.
Ławniczak-Jabłońska, K.
Zhuravlev, K. S.
Piskorska, E.
Nikiforov, A. I.
Welter, E.
Powiązania:
https://bibliotekanauki.pl/articles/2030656.pdf
Data publikacji:
2002-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
78.70.Dm
81.05.Gc
Opis:
Polarization-dependent X-ray absorption spectroscopy was used to study the local microstructure of Ge layers buried in silicon. The layers with thickness from 6 to 20 monolayers of Ge were grown by molecular beam epitaxy on Si substrate and were covered by Si (20 nm). To investigate the morphology of grown structures, X-ray absorption near edge structure and extended X-ray absorption fine structure analysis of the Ge K-edge was done. The performed qualitative analysis proves that X-ray absorption spectra are very sensitive to the local order in the formed structures and are sources of unique information about morphology of the buried Ge layers. Using these techniques we were able to observe the changes in atomic order around the Ge atoms in investigated buried layers and compare the formed atomic order with that in crystalline Ge. A substantial increase in intensity, broadening and chemical shift of the X-ray absorption near edge structure spectrum for 8 ML were observed. It can be related to the increase in density of electron states caused by increase in the localization of the states due to potential appearing at the Ge island boundaries and indicated the formation of quantum dots. The observed in-plane modulations of radial distribution and out-of-plane for different layers were discussed.
Źródło:
Acta Physica Polonica A; 2002, 101, 5; 709-717
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Photoemission Spectroscopy Study on the Contribution of the Yb 4f States to the Electronic Structure of ZnO
Autorzy:
Demchenko, I.
Melikhov, Y.
Konstantynov, P.
Ratajczak, R.
Barcz, A.
Guziewicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/1030972.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.55.hf
74.25.Jb
33.60.+q
Opis:
The electronic structure of Yb implanted ZnO has been studied by the resonant photoemission spectroscopy. The contribution of the Yb 4f partial density of states is predominant at binding energy about 7.5 and ≈11.7 eV below the VB maximum. At photon energy about 182 eV the multiplet structure around 11.7 eV shows the strongest resonance that corresponds to the ¹I multiplet which is almost exclusively responsible for this resonance, while ³H and ³F states are responsible for the resonance around 7.5 eV. It was also found that the Yb 4f partial density of states distribution shows some similarity to Yb₂O₃.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 907-909
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probabilistic approach for the determination of cuts permissible braking modes on the gravity humps
Вероятностный подход к определению допустимых режимов торможения отцепов на сортировочных горках
Autorzy:
Bobrovskyi, V.
Kozachenko, D.
Dorosh, A.
Demchenko, E.
Bolanovska, T.
Kolesnik, A.
Powiązania:
https://bibliotekanauki.pl/articles/374423.pdf
Data publikacji:
2016
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
marshalling yard
freight train
gravity hump
braking mode
brake position
stacja rozrządowa
pociąg towarowy
próg grawitacji
tryb hamowania
pozycja hamowania
Opis:
The paper presents the research results of cuts braking modes on the gravity humps. The objective of this paper is developing the methods for assessment of braking modes of cuts under conditions of fuzziness of their rolling properties, as well as selecting the permissible starting speed range of cuts from retardant positions. As a criterion for assessing the modes of target control of cut rolling speed, it was proposed to use an average gap size on a classification track at the established norms of probable exceeding of permissible speed of cars collision and their stop in retarders. As a criterion for evaluating the modes of interval control of cuts rolling speed, using the risk of their nonseparation on the switches was proposed. Using the simulation modeling and mathematical statistics, the configuration of the range of permissible speed of cuts coming out from retardant positions has been set. The conducted researches allow simplifying the choice of cut braking modes in systems of automatic control of cut rolling speed.
В статье представлены результаты исследований режимов торможе-ния отцепов на сортировочных горках. Целью статьи является разработка методов оценки режимов торможения отцепов в условиях неопределенности их ходовых характеристик, а также поиск области допустимых скоростей выхода отцепов из тормозных позиций. В качестве критерия для оценки режимов прицельного регу-лирования скорости скатывания отцепов предложено использовать среднюю вели-чину окна на сортировочном пути при установленных нормах вероятности превы-шения допустимых скоростей соударения вагонов и остановки их в замедлителях. В качестве критерия для оценки режимов интервального регулирования скорости скатывания отцепов предложено использовать риск их неразделения на стрелках. Спомощью методов имитационного моделирования и математической статистики установлена конфигурация области допустимых споростей выхода отцепов из тор-мозных позиций. Выполненные исследования позволяют упростить решение задачи выбора режимов торможения отцепов в системах автоматического управления скоростью их скатывания.
Źródło:
Transport Problems; 2016, 11, 1; 147-155
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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