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Wyszukujesz frazę "63.50.+x" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
Lattice Dynamics of Metallic Glass Ca$\text{}_{70}$Mg$\text{}_{30}$ on the Model of Bhatia and Singh
Autorzy:
Shukla, M. M.
Campanha, J. R.
Powiązania:
https://bibliotekanauki.pl/articles/1992705.pdf
Data publikacji:
1998-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.50.+x
Opis:
The lattice dynamical studies of the metallic glass Ca$\text{}_{70}$Mg$\text{}_{30}$ by Bhatia and Singh on their model contained two shortcomings, firstly the electron-ion interaction matrix was wrong and secondly, the numerical value of the bulk modulus of the electron gas was accepted arbitrarily. By modifying the electron-ion dynamical matrix and determining all the model parameters from the experimental data, we made a fresh study of the lattice dynamics of Ca$\text{}_{70}$Mg$\text{}_{30}$ and compared it to the earlier studies of Bhatia and Singh and also with experimental phonons.
Źródło:
Acta Physica Polonica A; 1998, 94, 4; 655-660
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon Dispersion in Amorphous Ni-Alloys
Autorzy:
Vora, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047350.pdf
Data publikacji:
2007-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.50.+x
65.60.+a
Opis:
The well-known model potential is used to investigate the longitudinal and transverse phonon dispersion curves for six Ni-based binary amorphous alloys, viz. Ni$\text{}_{31}$Dy$\text{}_{69}$, Ni$\text{}_{33}$Y$\text{}_{67}$, Ni$\text{}_{36}$Zr$\text{}_{64}$, Ni$\text{}_{50}$Zr$\text{}_{50}$, Ni$\text{}_{60}$ Nb$\text{}_{40}$, and Ni$\text{}_{81}$B$\text{}_{19}$. The thermodynamic and elastic properties are also computed from the elastic limits of the phonon dispersion curves. The theoretical approach given by Hubbard-Beeby is used in the present study to compute the phonon dispersion curves. Five local field correction functions proposed by Hartree, Taylor, Ichimaru-Utsumi, Farid et al. and Sarkar et al. are employed to see the effect of exchange and correlation in the aforesaid properties.
Źródło:
Acta Physica Polonica A; 2007, 111, 6; 859-871
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Spectra of In$\text{}_{0.30}$Se$\text{}_{0.70}$ Amorphous Films
Autorzy:
Weszka, J.
Daniel, Ph.
Burian, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2014453.pdf
Data publikacji:
2000-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Jv
63.50.+x
Opis:
Amorphous films of In$\text{}_{0.30}$Se$\text{}_{0.70}$ alloy thermally evaporated from one source onto borosilicate glass substrates were studied by Raman scattering at 300K and 10K. The Raman scattering spectra excited with 488 and 457.9nm laser lines were recorded in a quasi-rectangular geometry with the use of a single channel spectrometer. All the Raman scattering spectra reveal a continuum spreading from the Rayleigh line up to about 250cm$\text{}^{-1}$ and rather featureless background due to second-order processes beyond it. The room temperature spectra show a strong feature at about 143cm$\text{}^{-1}$ that is lacking in the spectra taken at 10K and, instead, a weak band at about 125cm$\text{}^{-1}$ is observed. The Raman scattering spectra recorded at both temperatures appear to be dependent on the excitation line within the 40-50cm$\text{}^{-1}$ range. The feature at about 143cm$\text{}^{-1}$ is attributed to Se chain modes while a weaker band at about 125cm$\text{}^{-1}$ observed at low temperature is due to Se$\text{}_{8}$ ring molecules. The dynamics of the In$\text{}_{0.30}$ Se$\text{}_{0.70}$ films is treated in terms of a continuous random network composed of rather strongly interconnected InSe$\text{}_{4}$ tetrahedral clusters.
Źródło:
Acta Physica Polonica A; 2000, 98, 5; 619-623
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering of Lattice Waves in Planar Surface with Grafted Adatomic Chains
Autorzy:
Aouchiche, H.
Kaddouri, A.
Powiązania:
https://bibliotekanauki.pl/articles/2038175.pdf
Data publikacji:
2004-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.+w
63.50.+x
63.20.Mt
Opis:
In the present work the scattering properties of a monolayer atomic lattice with grafted adatomic chains are investigated. In the case of two grafted lines, separated by a fixed distance, the localized states induced by the defect are determined. The transmission spectra are also obtained for various distances between the two chains and for additional chains regularly spaced. On the one hand, some Fabry-Perot oscillations are observed; their number is directly related to the number of adatomic lines. On the other hand, Fano resonances due to interaction between the localized states and the continuum are obtained. When the mass value of the adatom decreases, it is shown that the resonances move towards high frequencies in agreement with the harmonic oscillator frequency. Another novelty in this work consists of the observation of zeros of transmission in the spectra.
Źródło:
Acta Physica Polonica A; 2004, 106, 1; 25-37
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Damage Assessment in Low Doses $\text{}^{30}Si^{+}$-Implanted GaAs
Autorzy:
Desnica Franković, D.
Desnica, V.
Furić, K.
Powiązania:
https://bibliotekanauki.pl/articles/1807802.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Ly
61.72.Vv
63.50.+x
Opis:
Ion implantation is a widely used technique in device technology, and becoming even more important as the size of devices decreases. The studies of damage and introduced defects have been extensive and, although the overall development and annealing of the implantation damage is relatively well understood, many details remain unclear. Especially, not enough attention has been paid to the effects of very low doses, which are particularly important in controlling the threshold voltage of transistors in the fabrication of GaAs integrated circuits. The reason might be that the induced changes were very often below the detectivity limits of standard methods. In this work, we present the disorder analysis, conducted on GaAs implanted with low ion doses. Czochralski grown, undoped, (100) oriented GaAs samples were implanted with 100 keV $\text{}^{30}Si^{+}$ ions, doses ranging from 3×$10^{11}//cm^{2}$-3×$10^{13}//cm^{2}$, at 21°C. The damage assessment was done by applying Raman scattering and Rutherford backscattering ion channeling (RBS), linked by the inter-cascade distance model and the results were then compared with the results of photoacoustic displacement technique. We have shown that Raman scattering is very sensitive method even if applied on samples implanted with very low doses. Furthermore, the equivalency between the Raman scattering and Rutherford backscattering damage assessment, previously established for high doses via the inter-cascade distance model, proved equally valid also for very low implantation doses, where implanted ions create disordered cascades that are far apart, and most of the layer is still undamaged.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 42-46
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Spectroscopic Evidence of a Coherent Room Temperature Hybrid Structure of $BaTiO_3$ Single Crystal
Autorzy:
Liarokapis, E.
Antonakos, A.
Kojima, A.
Yoshimura, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1807818.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.-j
77.80.Dj
63.50.-x
Opis:
Recently, a precession X-ray study has discovered that ferroelectric $BaTiO_3$ single crystals have a coherent hybrid structure that consists of tetragonal and monoclinic lattices that share the (101) face of the tetragonal [11, 12]. Microscopic observations attest that the single crystal has two kinds of stripes (dark and white regions). Raman spectra of all sides of the cubic crystal have been collected at several scattering configurations. Two kinds of domains have been observed by the Raman measurements within the stripes, which are identified as light and dark spots under the optical microscope. The spectra structures and line widths are strongly affected when the laser direction is parallel to the b-axes and the polarization parallel to the a- or c-axes of the 90° domain (ac-side). It appears that there is a symmetry reduction and disorder, which affects the Raman active phonons. The results are in agreement with the coexistence of the two (tetragonal and monoclinic) lattices.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 68-71
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth-Selective Study of Surface Crystallization in NANOPERM-Type Alloys
Autorzy:
Miglierini, M.
Hatala, T.
Bujdoš, M.
Powiązania:
https://bibliotekanauki.pl/articles/1382582.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.80.+y
75.70.i
71.55.Jv
65.80.-g
63.22.-m
63.50.-x
Opis:
Evolution of structure and magnetic order is studied in the $\text{}^{57}Fe_{81}Mo_{8}Cu_{1}B_{10}$ alloy by conversion electron and conversion X-ray $\text{}^{57}Fe$ Mössbauer spectrometry. Surface features exhibit differences at both sides of ribbon-shaped samples with respect to the screening depth. In the as-quenched state, traces of magnetite (in addition to bcc-Fe) are revealed only at the wheel side of the ribbon to the depth of about 200 nm. It is present also after annealing up to 510 °C, then it disappears. In deeper regions (down to 1 μm), magnetite is less abundant. At the air side, only bcc-Fe is detected, though the progress of crystallization is more pronounced here than at the wheel side. Vibration properties of the bulk of amorphous and nanocrystalline samples are obtained from experiments of nuclear inelastic scattering of synchrotron radiation using partial densities of phonon states.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 56-57
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Hot Implantation on Residual Radiation Damage in Silicon Carbide
Autorzy:
Rawski, M.
Żuk, J.
Kulik, M.
Droździel, A.
Lin, L.
Prucnal, S.
Pyszniak, K.
Turek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1504145.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.U-
78.30.-j
61.05.Np
63.50.-x
79.20.Rf
81.70.Fy
Opis:
Remarkable thermomechanical and electrical properties of silicon carbide (SiC) make this material very attractive for high-temperature, high-power, and high-frequency applications. Because of very low values of diffusion coefficient of most impurities in SiC, ion implantation is the best method to selectively introduce dopants over well-defined depths in SiC. Aluminium is commonly used for creating p-type regions in SiC. However, post-implantation radiation damage, which strongly deteriorates required electric properties of the implanted layers, is difficult to anneal even at high temperatures because of remaining residual damage. Therefore implantation at elevated target temperatures (hot implantation) is nowadays an accepted method to decrease the level of the residual radiation damage by avoiding ion beam-induced amorphization. The main objective of this study is to compare the results of the Rutherford backscattering spectroscopy with channeling and micro-Raman spectroscopy investigations of room temperature and 500°C $Al^{+}$ ion implantation-induced damage in 6H-SiC and its removal by high temperature (up to 1600°C) thermal annealing.
Źródło:
Acta Physica Polonica A; 2011, 120, 1; 192-195
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-Principles Study of the Structural, Elastic, and Mechanical Properties of $Ni_3Ga$ Compound under Pressure
Autorzy:
Boucetta, S.
Zegrar, F.
Powiązania:
https://bibliotekanauki.pl/articles/1206272.pdf
Data publikacji:
2014-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.dk
62.20.de
62.20.-x
62.50.-p
Opis:
There was employed the density functional theory plane-wave pseudopotential method with local density approximation and generalized gradient approximation to investigate the structural, elastic and mechanical properties of the intermetallic compound $Ni_3Ga$. The calculated equilibrium lattice constant and bulk modulus are in good agreement with the experimental values. The elastic constants were determined from a linear fit of the calculated stress-strain function according to Hooke's law. From the elastic constants, the bulk modulus B, anisotropy factor A, shear modulus G, Young's modulus E and Poisson's ratio υ for $Ni_3Ga$ compound are obtained. Our results for the bulk modulus B, anisotropy factor A, shear modulus G, Young's modulus E and Poisson's ratio υ are consistent with the experimental values. The sound velocities and the Debye temperature are also predicted from elastic constants. The dependences of the elastic and mechanical properties of $Ni_3Ga$ compound on pressure were investigated for the first time. It was found that the cubic $Ni_3Ga$ compound is mechanically stable according to the elastic stability criteria and it is not elastically isotropic. By analyzing the ratio B/G, it was concluded that $Ni_3Ga$ compound is ductile in nature.
Źródło:
Acta Physica Polonica A; 2014, 125, 1; 54-59
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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