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Tytuł:
Quasiclassical Theory of Spin-Valve Magnetoresistance: Role of Spin-Flip Scattering
Autorzy:
Baksalary, O. M.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955445.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Jn
72.15.Gd
Opis:
The Boltzmann kinetic equation is used to analyse the in-plane electronic transport in magnetic multilayers. Both diffuse and electron-momentum-conserving spin-flip scattering processes are included. Numerical results show that the momentum-conserving scattering processes reduce the spin-valve magnetoresistance.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 261-264
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intrinsic Luminescence of the Undoped Glasses of (CaO-Ga$\text{}_{2}$O$\text{}_{3}$-GeO$\text{}_{2}$) System
Autorzy:
Padlyak, B. V.
Bordun, O. M.
Buchynskii, P. P.
Powiązania:
https://bibliotekanauki.pl/articles/2010938.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Ce
78.60.-b
76.30.Mi
Opis:
For the first time the intrinsic luminescence in the undoped (CaO-Ga$\text{}_{2}$O$\text{}_{3}$-GeO$\text{}_{2}$) glasses with different composition has been found and investigated in the 80÷300 K temperature range. The new glasses of high chemical purity and optical quality with stoichiometric composition similar to that in calcium-gallium- germanium garnet (Ca$\text{}_{3}$Ga$\text{}_{2}$Ge$\text{}_{3}$O$\text{}_{12}$), trigonal Ca-gallogermanate (Ca$\text{}_{3}$Ga$\text{}_{2}$Ge$\text{}_{4}$O$\text{}_{14}$), and Ca$\text{}_{3}$Ga$\text{}_{2}$O$\text{}_{6}$ crystals were obtained by the high-temperature synthesis method. The luminescence and photoexcitation spectra analysis, supported by EPR spectroscopy data, yields the following results: (i) the UV-excited non-elementary broad emission band with maxima at roughly 500 nm and 420 nm in the (CaO-Ga$\text{}_{2}$O$\text{}_{3}$-GeO$\text{}_{2}$) glasses is due to recombination of ensemble of the transient hole O$\text{}^{-}$ centres; (ii) the emission bands with maxima at nearly 380 and 710 nm, which were distinctly revealed in glasses with the Ca$\text{}_{3}$Ga$\text{}_{2}$Ge$\text{}_{4}$O$\text{}_{14}$ and Ca$\text{}_{3}$Ga$\text{}_{2}$O$\text{}_{6}$ compositions, are assigned to the luminescence of UV-induced electron centres of two different types. Possible models of the luminescence centres in (CaO-Ga$\text{}_{2}$O$\text{}_{3}$-GeO$\text{}_{2}$) glass network are discussed.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 921-929
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metal Surface Dipole Moment and Work Function in the Linear Potential Model
Autorzy:
Mohammed, A. E.
Ghaly, A. Y.
Frege, O. M.
Powiązania:
https://bibliotekanauki.pl/articles/1891682.pdf
Data publikacji:
1991-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.30.+y
Opis:
Jellium metal surface properties such as the surface dipole barrier and work function are obtained in the linear potential approximation to the effective potential at the surface. The metal surface position and field strength are determined respectively by the requirement of overall charge neutrality and the constraint set on the electrostatic potential by the Budd-Vannimenus theorem. The calculations are primarily analytic and these properties are given in terms of universal functions of the field strength. The results obtained employing the Ceperly-Alder expression for the correlation energy closely approximate those of Lang and Kohn.
Źródło:
Acta Physica Polonica A; 1991, 80, 4; 591-600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrically Detected Magnetic Resonance
Autorzy:
Fedorych, O. M.
Wilamowski, Z.
Jantsch, W.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2038127.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Pk
72.25.Rb
73.21.Fg
Opis:
We compare the results of electrically detected magnetic resonance in a 2D electron gas in Si/SiGe quantum wells with transport and magnetic resonance measurements on ferromagnetic Ga$\text{}_{1-x}$Mn$\text{}_{x}$As. The results lead us to the conclusion that observation of electrically detected magnetic resonance is possible only in the case of a slow spin relaxation, where the microwave resonant absorption leads to a noticeable change of spin magnetization.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 591-598
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Resonance Studies of the Origin of Ferromagnetism in Ga$\text{}_{1-x}$Mn$\text{}_{x}$As
Autorzy:
Fedorych, O. M.
Wilamowski, Z.
Potemski, M.
Byszewski, M.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2036029.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
76.30.Fc
75.50.Pp
75.30.Gw
Opis:
Different types of magnetic resonance observed in Ga$\text{}_{1-x}$Mn$\text{}_{x}$As reflect three different magnetic phases: para-, ferro-, and ferrimagnetic. Ferromagnet is characterized by single isotropic resonance line. A complex spectrum in ferrimagnet can be described by g factor equal to 1.44 and a sum of an axial and cubic anisotropy field. The axial field is by an order of magnitude greater than the cubic one. The complex structure of ferrimagnetic resonance is attributed to spin-wave resonance. Quantitative analysis of the dispersion of spin wave shows that the range of exchange coupling is very long, of the order of 25 nm, while spin-wave stiffness and the total exchange field are very small. The exchange field as evaluated from spin wave is by two orders of magnitude smaller than the Zener field corresponding to the critical temperature.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 607-612
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:
Investigation of Effects of Parameters in Element-Free Galerkin Method for Bending Analysis of Mindlin-Reissner Plates
Autorzy:
Bozkurt, Ö.
Barbar, M.
Özbek, Ö.
Powiązania:
https://bibliotekanauki.pl/articles/1401977.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
45.10.-b
Opis:
The element-free Galerkin method is one of the most widely used meshfree method in solid mechanics due to its simplicity and high convergence rate. However, it has some selectable parameters that affect the accuracy and convergence. The parameters can be listed as size of support domain, number of monomials, type of weight function, number of integration points in a background cell and value of penalty coefficient. The effects of these parameters on the accuracy of the element-free Galerkin method solution of the Reissner-Mindlin plate bending are investigated. A number of case studies with regular and irregular node distributions are solved. The displacement and moment values at critical points are compared with exact solutions. It is shown that the selectable parameters have to be carefully selected especially for the analysis of moments.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-208-B-210
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Pulse Duration on Structure and Surface Characteristics of Micro-Arc Oxidation Coatings Formed on Aluminum Alloy
Autorzy:
Yilmaz, M.
Şahin, O.
Powiązania:
https://bibliotekanauki.pl/articles/1186801.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.15.-z
81.16.Pr
Opis:
Micro arc oxidation (MAO) of aluminum alloy samples was studied using bipolar pulses with various pulse durations under constant duty cycle. The processing times were chosen as 20, 30 and 40 minutes. The X-ray diffraction (XRD) technique, scanning electron microscope (SEM), surface roughness measurement (R_a) and indentation tests were employed to investigate the phase distribution, microstructure, surface properties and hardness of the coatings, respectively. By increasing the pulse duration and processing time, coatings with different surface roughness, thickness and hardness were fabricated.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 673-676
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Overlapping Muffin-Tin Approximation
Autorzy:
Zwierzycki, M.
Andersen, O.
Powiązania:
https://bibliotekanauki.pl/articles/1810287.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.-m
71.15.Ap
Opis:
We present the formalism and demonstrate the use of the overlapping muffin-tin approximation. This fits a full potential to a superposition of spherically symmetric short-ranged potential wells plus a constant. For one-electron potentials of this form, the standard multiple-scattering methods can solve Schrödingers' equation correctly to 1st order in the potential overlap. Choosing an augmented-plane-wave method as the source of the full potential, we illustrate the procedure for diamond-structured Si. First, we compare the potential in the Si-centered overlapping muffin-tin approximation with the full potential, and then compare the corresponding overlapping muffin-tin approximation N-th order muffin-tin orbital and full-potential linear augmented plane wave band structures. We find that the two latter agree qualitatively for a wide range of overlaps and that the valence bands have a root mean squared deviation of 20 meV/electron for 30% radial overlap. Smaller overlaps give worse potentials and larger overlaps give larger 2nd-order errors of the multiple-scattering method. To further remove the mean error of the bands for small overlaps is simple.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 64-68
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Conductivity in Open Cylindrical Two-Barrier Symmetric Resonance Tunnel Structure
Autorzy:
Tkach, M.
Makhanets, O.
Seti, Ju.
Dovganiuk, M.
Voitsekhivska, O.
Powiązania:
https://bibliotekanauki.pl/articles/1537805.pdf
Data publikacji:
2010-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.Hb
73.21.La
73.40.Gk
Opis:
The theory of resonance energies and widths of electron quasi-stationary states and electronic conductivity in open cylindrical two-barrier symmetric resonance tunnel structure is developed. The complete Schrodinger equation is solved within the model of effective masses for rectangular potential wells and barriers. Interaction between electrons and electromagnetic field was taken into account using the approximation of the small signal. The calculations of spectral parameters are performed for $In_{0.53}Ga_{0.47}As$/$In_{0.52}Al_{0.48}As$ resonance tunnel structure. The dependences of conductivity on the energy of mono-energy electrons beam falling at the system and electromagnetic field energy absorbed or emitted by the system are obtained and analyzed. The relation between experimentally measured parameters of conductivity and resonance widths of electron quasi-stationary states in open resonance tunnel structure is established.
Źródło:
Acta Physica Polonica A; 2010, 117, 6; 965-970
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Boronizing on the Oxidation Resistance of 316L Stainless Steel
Autorzy:
Khenifer, M.
Allaoui, O.
Taouti, M.
Powiązania:
https://bibliotekanauki.pl/articles/1031181.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
316L stainless steel
boronizing
high temperature oxidation
oxidation kinetics
rate constant
Opis:
The effect of boronizing treatment on oxidation at high temperature on 316L stainless steel was studied at 850, 900, 950, and 1000°C in air, for holding times between 0.25 and 24 h. The oxidation resistance of unboronized and boronized specimens was studied isothermally by thermogravimetric analyzer. The oxidation rate constant represented as a parabolic rate constant K_{p} was evaluated. Optical microscopy, X-ray diffraction, and the scanning electron microscopy were used for surface characterizations. The experimental results show that boronized coating increases the resistance of stainless steel 316l about twice and prevents oxygen from penetrating into the stainless steel substrate at the temperatures between 850 and 1000°C.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 518-520
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excitation Functions of Neutron Induced Nuclear Reactions for ⁵⁹Co Nucleus using Different Level Density Models
Autorzy:
Korkmaz, M.
Yigit, M.
Agar, O.
Powiązania:
https://bibliotekanauki.pl/articles/1031325.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
21.10.Ma
Opis:
Cobalt alloys have been used in nuclear reactor design because these alloys have favourable mechanical properties at high temperatures. In this work, the nuclear cross section data of ⁵⁹Co(n,2n)⁵⁸Co, ⁵⁹Co(n,3n)⁵⁷Co, ⁵⁹Co(n,4n)⁵⁶Co, ⁵⁹Co(n,np)⁵⁸Fe, ⁵⁹Co(n,t)⁵⁷Fe, ⁵⁹Co(n,³He)⁵⁷Mn and ⁵⁹Co(n,2nα)⁵⁴Mn reactions were obtained by using TALYS 1.8 and ALICE/ASH codes. Effects on the cross section data of nuclear level density models in the calculations were investigated. In addition, the obtained results of the cross section calculations are discussed and compared with the measured values from the literature.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 670-673
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical determination of casting-mold interfacial heat transfer coefficient in the high pressure die casting of A-360 aluminum alloy
Autorzy:
Koru, M.
Serçe, O.
Powiązania:
https://bibliotekanauki.pl/articles/1061546.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
47.11.Bc
47.27.ek
44.10.+i
Opis:
Although die casting is a near net shape manufacturing process, it mainly involves a thermal process. Therefore, in order to produce high quality parts, it is important to determine casting-mold interfacial heat transfer coefficient and heat flux. In this paper the effects of different injection parameters (second phase velocity, injection pressure, pouring and die temperature) on heat flux and interfacial heat transfer coefficient were investigated experimentally and numerically. Experiments were performed in cylindrical geometry using a cast aluminum alloy A360 against H13 steel mold. Selected injection parameters were 1.7-2.5 m/s for second phase velocity, 100-200 bar for third phase pressure, 983-1053 K for pouring temperature and 373, 433, 493, 553 K for the die temperature. These parameters were used for both non-vacuum and vacuum conditions in the cavity of the mold. The effects of the application under vacuum conditions were also studied. Temperatures were measured as functions of time, using 18 thermocouples, which were mounted at different depths of casting and mold material. Measured and calculated temperature values are found compatible. Interfacial heat transfer coefficient h and heat flux q depending on the experimentally measured temperature values were calculated with finite difference method using explicit technique in C# programming language. In addition to experiments, Flow-3D software simulations were performed using the same parameters. Interfacial heat transfer coefficient and heat flux results obtained from Flow-3D are also presented in the study. Interfacial heat transfer coefficient has decreased as a result of increasing of temperature of mold and pouring. In addition, interfacial heat transfer coefficient values have increased slightly with the increase of injection speed and pressure. It was observed that the values of interfacial heat transfer coefficient and heat flux have also increased when vacuum was applied inside the cavity of the mold. When all injection parameters are considered, it is seen that the interfacial heat transfer coefficient varies between 92-117 kW/m² K.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 453-458
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solid-state NMR study of poly(3-hydroxybutyrate) and Ecoflex reser blends
Autorzy:
Hutníková, M.
Fričová, O.
Powiązania:
https://bibliotekanauki.pl/articles/1070537.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.35.Lr
82.56.Na
Opis:
Biodegradable blends of poly(3-hydroxybutyrate) and aromatic-aliphatic co-polyester Ecoflex® were studied by means of basic solid-state NMR techniques. ^{13}C NMR spectra pointed at existence of individual components in blends, however, existence of regions in which components affect each other was also deduced from changes of shape of some spectral lines. Analysis of proton spin-lattice relaxation process in laboratory frame running in blends with different fractions of components revealed poor miscibility of these polymers. The domain size of components was calculated based on the values of spin-lattice relaxation times in laboratory frame. Spin-lattice relaxation process in the rotating frame of Ecoflex® proton spin system was only slightly influenced by the blending. Incompatibility of these polymers was confirmed by all realized experiments.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 388-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Resonant Dynamic Magnetization Distribution in Ferromagnetic Thin Film with the Antidot
Autorzy:
Busel, O.
Zelent, M.
Gorobets, O.
Gorobets, Yu.
Krawczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030769.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Ds
75.70.-i
75.78.-n
Opis:
The influence of homogeneous dynamic microwave magnetic field applied to the permalloy (Py) thin film with a single circular antidot on the magnetization dynamics was theoretically investigated. It was considered that the Py film is saturated by the external constant magnetic field along the direction perpendicular to the film plane. The linearized Landau-Lifshitz equation was applied in order to create an analytical model of small deviations from the equilibrium values of the magnetization and magnetic field. Conditions of the local ferromagnetic resonances were defined and the dependency of resonance frequency on the magnetic field magnitude was visualized. The model has shown that the amplitude of the resonant magnetization oscillations is localized near the antidot edge and their position is dependent on the frequency.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 492-494
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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