Temat: 61.72.J- - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Precipitation Effects in Mg-Zn Alloys Studied by Positron Annihilation and Hardness Testing
Autorzy:: Hruška, P.
Čížek, J.
Vlček, M.
Melikhova, O.
Procházka, I.
Tematy:: 78.70.Bj
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1196079.pdf Link otwiera się w nowym oknie
Opis:: In the present work positron annihilation spectroscopy combined with Vickers hardness testing were employed in order to investigate precipitation effects in Mg-Zn alloys. It was found that incoherent precipitates of a metastable Zn-rich phase formed in the samples isochronally annealed above 200C cause hardening of the alloy.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Investigation of Precipitation Effects in Mg-Tb and Mg-Tb-Nd Alloys
Autorzy:: Vlček, M.
Čížek, J.
Melikhova, O.
Hruška, P.
Procházka, I.
Tematy:: 78.70.Bj
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1196115.pdf Link otwiera się w nowym oknie
Opis:: Investigation of precipitation effects in solution treated Mg-Tb and Mg-Tb-Nd alloy was performed. Solution treated alloys were compared with samples deformed by high pressure torsion to examine influence of deformation on precipitation effects. Dislocations present in samples processed by high pressure torsion can serve as diffusion channels for atoms and also as nucleation sites for precipitates. Therefore precipitation of some phases in high pressure torsion deformed samples was observed at lower temperatures than in solution treated ones.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Defects Studies of ZnO Single Crystals Prepared by Various Techniques
Autorzy:: Lukáč, F.
Čížek, J.
Procházka, I.
Melikhova, O.
Anwand, W.
Brauer, G.
Tematy:: 78.70.Bj
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1196118.pdf Link otwiera się w nowym oknie
Opis:: The aim of the present work was a comparison of defects in ZnO crystals grown by various techniques available nowadays, namely hydrothermal growth, pressurized melt, Bridgman method growth and vapor phase growth. Positron annihilation spectroscopy was employed as a principal tool for characterization of defects in ZnO crystals grown by above mentioned various techniques. ZnO crystals can be divided into two groups: (i) hydrothermal grown crystals, which exhibit positron lifetime of 179-182 ps and (ii) ZnO crystals grown by the other techniques (pressurized melt, Bridgman method, vapor phase growth) which are characterized by the lower lifetimes falling in the range of 160-173 ps. Comparison of experimental data with ab initio theoretical calculations revealed that HT grown ZnO crystals contains Zn vacancies associated with hydrogen atom in a bond-centered site. On the other hand, ZnO crystals prepared by other techniques contain most probably stacking faults created by stresses induced by temperature gradients in the melt.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Investigation of Carrier Recombination in Si Heavily Irradiated by Neutrons
Autorzy:: Gaubas, E.
Kadys, A.
Uleckas, A.
Vaitkus, J.
Tematy:: 61.72.J-
61.82.Fk
72.40.+w; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1813194.pdf Link otwiera się w nowym oknie
Opis:: Variations of recombination lifetime, with fluence of the reactor neutrons from $10^{12}$ to $3×10^{16} n//cm^2$, in the magnetic field applied Czochralski grown Si samples are examined by the contactless transient techniques of the microwave probed photoconductivity and dynamic gratings. A nearly linear decrease in lifetime from few microseconds to about 200 ps within the examined range of neutron irradiation fluences was obtained. This dependence persists under relatively low (≤80°C) temperature heat treatments. Also, cross-sectional scans of lifetime depth-profiles were examined, which show rather high homogeneity of lifetime values within wafer thickness.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Nanoscale deformation of GaAs affected by silicon doping
Autorzy:: Majtyka, A.
Nowak, R.
Chrobak, D.
Tematy:: 64.70.kg
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1112264.pdf Link otwiera się w nowym oknie
Opis:: Effect of silicon doping on the elastic-plastic transition of GaAs crystal is demonstrated by results of nanoindentations and ab initio simulations. The performed experiments show that an increase of silicon concentration causes a decrease of the contact pressure at the onset of permanent nanodeformation of GaAs crystal. Ab initio calculations demonstrate that presence of Si atoms in the crystal lattice suppresses the shear modulus as well as the pressure of equilibrium between zinc-blende and rock-salt phases of GaAs. Furthermore, it is argued that the effect of dislocations pinning to Si dopants is essential for clarification of GaAs yielding.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Point Defects in Magnesium Aluminates Spinel Ceramics Doped with Lithium Fluoride
Autorzy:: Gritsyna, V.
Kazarinov, Yu.
Moskvitin, A.
Reimanis, I.
Tematy:: 81.05.Je
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1550494.pdf Link otwiera się w nowym oknie
Opis:: The nature and topological distribution of optical centers within various regions of hot pressed disks of transparent magnesium aluminates spinel ceramics doped with LiF were studied. In the optical absorption spectra of this type of ceramic, bands were revealed at 4.75 eV and 5.3 eV, which were identified with $F^{+}-$ and F-centers, respectively. Because both bands are formed by anionic vacancies which captured one or two electrons, the topological distribution of anionic vacancies was determined. The band at 5.65 eV was also found which is tentatively identified with complex centers of anionic vacancies that capture fluorine ions and electrons. Using X-ray irradiation the variety of absorption bands of hole centers related to cationic vacancies was established. The spatial distribution of cationic vacancies within the ceramic disk was also determined.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Study of Oxide-Dispersion-Strengthened Ferritic Steels after Ion Implantation
Autorzy:: Simeg Veternikova, J.
Korhonen, E.
Skarba, M.
Degmova, J.
Sabelova, V.
Sojak, S.
Slugen, V.
Tematy:: 61.72.-y
68.55.Ln
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1336688.pdf Link otwiera się w nowym oknie
Opis:: This paper is focused on four different commercial oxide-dispersion-strengthened ferritic steels (MA 956, ODM 751, MA 957 and ODS Eurofer) with different chromium content and the change of their microstructure after helium ion implantation. The samples were implanted with kinetic energy of ions up to 500 keV and the implantation depth was up to 1.2 μm. The implantation was performed at Institute of Nuclear and Physical Engineering, Slovak University of Technology in Bratislava. The samples were observed prior and after the implantation by positron Doppler broadening spectroscopy with slow positron beam (energy up to 36 keV) which is one of the most suitable techniques due to its sensitivity to surface and subsurface layers up to 1.6 μm. The results showed visible change of defect presence in all samples and defect depth profiles are in a good accordance with SRIM software calculations displaying the Bragg peak. According to measured data, ODS Eurofer (9% Cr) seems to be the most radiation resistant from the group of all investigated steels and MA 956 (20% Cr) as the most radiation affected steel.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Comparison of Grain Boundary Structure in Metals and Semiconductors as Probed by Positrons
Autorzy:: Kuriplach, J.
Tematy:: 71.60.+z
61.72.Mm
61.72.J-
78.70.Bj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1196087.pdf Link otwiera się w nowym oknie
Opis:: Vacancy behavior and positron trapping at selected grain boundaries in iron, nickel, and zirconia are investigated theoretically. It is found that the grain boundary vacancy loses its free volume in metals at moderate temperatures whereas it is kept up to very high temperatures in zirconia. The consequences of these findings for positron annihilation studies of nanocrystalline materials are discussed.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 9.

Tytuł:: Induced Absorption in Gadolinium Gallium Garnet Irradiated by High Energy $\text{}^{235}U$ Ions
Autorzy:: Potera, P.
Ubizskii, S.
Sugak, D.
Schwartz, K.
Tematy:: 61.72.jn
81.40.Wx
61.80.Ba
61.80.Jh
61.72.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1550538.pdf Link otwiera się w nowym oknie
Opis:: The present work is devoted to investigation of optical absorption in pure $Gd_{3}Ga_{5}O_{12}$ (GGG) single crystals in the spectral range 0.2-1.1 μm induced under influence of the $\text{}^{235}U$ ions irradiation with energy 2640 MeV and a fluence $10^{9}-10^{11} cm^{-2}$. The induced absorption for $10^{9} cm^{-2}$ is caused by recharging of point defects, both growth ones and impurities. After irradiation by $\text{}^{235}U$ ions with fluences starting from $3 \times 10^{9} cm^{-2}$ the absorption rise is probably caused by contribution of the lattice destroying as a result of heavy ion bombardment as well as radiation displacement defects.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Native Deep-Level Defects in MBE-Grown p-Type CdTe
Autorzy:: Olender, K.
Wosiński, T.
Mąkosa, A.
Dłużewski, P.
Kolkovsky, V.
Karczewski, G.
Tematy:: 71.55.Gs
68.37.Lp
61.72.J-
61.72.Lk; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1492964.pdf Link otwiera się w nowym oknie
Opis:: Deep-level transient spectroscopy was used to study the defect levels in p-type CdTe layers grown by the molecular-beam epitaxy technique on lattice-mismatched GaAs substrates. In our measurements we have observed five hole traps. Two of the traps, displaying exponential capture kinetics, have been assigned to native point defects, the Cd vacancy and a complex formed of Cd vacancy and Te antisite, produced in the CdTe layers during their growth. The other two traps have been attributed to electronic states of threading dislocations on the ground of their logarithmic capture kinetics. The last trap, which was observed only when the investigated space charge region was close to the metal-semiconductor interface, has been ascribed to surface states.
Dostawca treści:: Biblioteka Nauki

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