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Wyszukujesz frazę "J. M-A." wg kryterium: Autor


Tytuł:
Correlation Functions in the Spin-fermion Model
Autorzy:
Bała, J.
Oleś, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2012895.pdf
Data publikacji:
2000-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
75.10.-b
74.72.-h
79.60.-i
Opis:
We show that the quasiparticle states found in a self-consistent Born approximation for the spin-fermion model which describes CuO$\text{}_{2}$ planes agree well with experimental data in insulating Sr$\text{}_{2}$CuO$\text{}_{2}$Cl$\text{}_{2}$. It is found that the antiferromagnetic correlations are reduced in the neighbourhood of a moving oxygen hole and the correlation functions can exhibit similar dipolar distortions as reported in the context of the t-J model.
Źródło:
Acta Physica Polonica A; 2000, 97, 1; 213-216
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Density Functional Studies of Nonlinear Elastic Properties for Zinc-Blende Nitrides
Autorzy:
Łopuszyński, M.
Majewski, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2047721.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.20.Dc
43.25.+y
62.50.+p
Opis:
In this paper we present a method of calculating third-order elastic constants C$\text{}_{ijk}$ and its application to zinc-blende nitrides AlN, GaN, and InN. Our approach is based on accurate ab initio calculations of both energy and stress as a function of applied strain. Ab initio computations are performed within density functional theory framework. To assess the reliability of the presented method, we compare our theoretical findings for GaAs with experimental results for C$\text{}_{ijk}$ available for this material.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 443-447
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Time Dependent Features of the Two-Colour Light Pulses Propagation in the Sodium Vapour
Autorzy:
Alhasan, A. M.
Fiutak, J.
Powiązania:
https://bibliotekanauki.pl/articles/2044631.pdf
Data publikacji:
2006-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.50.Md
42.65.-k
42.50.Hz
Opis:
The phase and group velocities of the pulsed light are suitably defined and calculated. So are the duration of both pulses, probe and coupling, and their energies as a function of the travelled distance. The time evolution, for a given distance, of the dressed atom state is described by the Liouville-von Neumann equation for the density matrix.
Źródło:
Acta Physica Polonica A; 2006, 109, 2; 143-157
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Origin of Centres Involved in Blue and Orange Luminescence of 6H-SiC
Autorzy:
Wysmołek, A.
Baranowski, J. M.
Kamińska, M.
Powiązania:
https://bibliotekanauki.pl/articles/1934050.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.-m
78.20.-e
78.60.Kn
Opis:
We present new results of luminescence of n-type 6H-SiC crystals. We have found two shallow donors with ionization energies at 60 meV and 140 meV. We have shown that the blue luminescence is not affected by the ionization of the shallower donor and is related to deeper donor which we attribute to N at C-site. We propose that the origin of the more shallower donor at 60 meV is related to carbon vacancy. We have found that the intensity of the orange luminescence increases under infrared illumination. This result confirms that the orange luminescence is due to conduction band-deep centre transitions. We believe that deep centre responsible for the orange luminescence is the silicon vacancy.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 957-960
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Orbit Coupling in Cr$\text{}^{3+}$ Ion in Solid State Materials
Autorzy:
Wojtowicz, A. J.
Grinberg, M.
Łempicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1879947.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
Opis:
In this paper we introduce a new model describing the coupling of $\text{}^{2}$E and $\text{}^{4}$T$\text{}_{2}$ states of octahedrally coordinated Cr$\text{}^{3+}$ ion, which includes spin-orbit and electron-lattice interactions and takes into account the electronic structure of both states. The model is used to calculate doublet lifetime. We have applied this model to the series of Cr$\text{}^{3+}$ doped garnets characterized by the varying crystal field parameter 10 Dq and O$\text{}_{h}$ symmetry of the Cr site and to the kyanite (Al$\text{}_{2}$O$\text{}_{3}$:SiO$\text{}_{2}$), which is the case of different Cr$\text{}^{3+}$ sites in one material, characterized by the relatively large component of the low symmetry crystal field. The agreement with experiment is reasonable.Z
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 235-238
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Field Magnetic Properties of FeCo-Based Alloys
Autorzy:
Hasiak, M.
Miglierini, M.
Łukiewska, A.
Kaleta, J.
Zbroszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1378307.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.80.+y
75.50.Kj
75.60.Lr
71.55.Jv
Opis:
Low field magnetic properties of amorphous $(Fe_{x}Co_{1})_{76}Mo_{8}Cu_{1}B_{15}$ alloys (x=3, 6 and 9) were characterized by magnetic after-effect and initial magnetic susceptibility. Activation energies and pre-exponential factors of the Arrhenius law that were derived from the disaccommodation curves are of about 1.188 eV and $10^{-15}$ s, respectively. Local magnetic arrangement was investigated by $\text{}^{57}Fe$ Mössbauer spectrometry. The average hyperfine magnetic field decreases with increasing Fe/Co ratio due to smaller relative contribution of cobalt. The overall magnetic parameters of the alloy prove its good soft magnetic properties with an application potential.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 118-119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Secondary Electroluminescence on Cathodoluminescence and Other Luminescence Measurements
Autorzy:
Pluska, M.
Czerwinski, A.
Szerling, A.
Ratajczak, J.
Kątcki, J.
Powiązania:
https://bibliotekanauki.pl/articles/1198425.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Hk
85.30.De
61.72.-y
68.37.Hk
Opis:
Cathodoluminescence and photoluminescence measurements are commonly accepted as revealing local properties of a specimen region excited by a beam of electrons or photons. However, in the presence of a strong electric field (e.g. a junction) an electron (or light/laser) beam-induced current is generated, which spreads over the structure. A secondary non-local electroluminescence, generated by this current and detected together with the expected luminescence signal, may strongly distort measurement results. This was confirmed by cathodoluminescence measurements on test structures prepared by focused ion beam on AlGaAs/GaAs/InGaAs laser heterostructures. Methods for minimizing the distortion of measured luminescence signals are presented.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 1027-1032
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of Nanoelectronic-Structure Defect Detection by Cathodoluminescence on Electron Beam Current
Autorzy:
Pluska, M.
Czerwinski, A.
Ratajczak, J.
Szerling, A.
Kątcki, J.
Powiązania:
https://bibliotekanauki.pl/articles/1807514.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Hk
85.30.De
61.72.-y
Opis:
The dependence of defect detection by cathodoluminescence in a scanning electron microscope on the electron beam current is considered. The examined specimens are AlGaAs/GaAs laser heterostructures with InGaAs quantum well. It is shown that for low electron beam currents, which are typically used, the uniform cathodoluminescence is observed, while for the increasing high electron beam current the oval defects become more and more visible. The influence of electrical properties of the structure on the luminescence detection is explained.
Źródło:
Acta Physica Polonica A; 2009, 116, S; S-86-S-88
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo Simulations of Ferromagnetic Nanocomposites
Autorzy:
Woińska, M.
Majhofer, A.
Gosk, J.
Szczytko, J.
Powiązania:
https://bibliotekanauki.pl/articles/1403635.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Mg
75.50.Tt
75.75.-c
Opis:
We present results of Monte Carlo simulations of a model system of Co nanoparticles in an external magnetic field. In our simulations we take into account the interaction with the external magnetic field, the energy of crystallographic anisotropy and the dipole-dipole interactions between single domain nanoparticles. We apply the standard Metropolis algorithm to a cluster of 27 randomly distributed superparamagnetic Co nanoparticles. We investigate the dependence of blocking temperature $T_{B}$ on particle and cluster size.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1019-1021
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue Characteristics of Laser Welded DC06EK and DP600MC Steel Sheets
Autorzy:
Mihaliková, M.
Lišková, A.
Hagarová, M.
Cervová, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032913.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
automotive steel
laser welding
fatigue
microhardness
Opis:
Welding of different types of steel is fundamental proces for the production of car bodies. Fatigue degradation is still a significant factor in long-term use. Current trends welding and combinations of different types of steel are used. The specific form of the course of fatigue in the welded joints is followed. Test samples loaded fatigue tests, microscopic and scanning electron microscopy analysis of welded joints of steel type IF (DC06EK) and DP (DP600MC) are done. The resulting values of endurance tests are graphically processed by the Wöhler curve.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1347-1350
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoneutralization of the Fe$\text{}^{3+}$ Centers in the ZnSe Crystals Heavily Doped with Iron
Autorzy:
Lubomirska-Wittlin, A.
Szadkowski, A. J.
Demianiuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1886786.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.40.+w
71.55.Gs
Opis:
Photoconductivity and optical quenching of the photoconductivity were measured. The photoneutralization of the Fe$\text{}^{3+}$ centres has been found to occur for photon energies down to 0.8 eV (i.e. the threshold can not be at 1.1 eV, as often quoted). The conclusion from our previous paper that the lattice relaxation energy is small, has been confirmed. It has to be smaller than 0.1 eV.
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 337-340
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Transfer, Fluorescence and Scintillation Processes in Cerium-Doped RE$\text{}^{3+}$ AlO$\text{}_{3}$ Fast Scintillators
Autorzy:
Mares, J. A.
Nikl, M.
Powiązania:
https://bibliotekanauki.pl/articles/1945462.pdf
Data publikacji:
1996-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.-m
78.60.-b
Opis:
Modern applications of scintillators in medical imaging of human body (Positron Emission Tomography - PET scanning, γ-cameras and other X-ray tomographies) require improved or even quite new scintillators which should be characterized by (i) fast response, (ii) high density and (iii) high light yield. At present time new scintillating crystals are investigated, mainly those having perovskite lattice structure of the formula RE$\text{}^{3+}$ AlO$\text{}_{3}$:Ce where RE $\text{}^{3+}$ = Y$\text{}^{3+}$, Gd$\text{}^{3+}$ and Lu$\text{}^{3+}$. Here, we will present the newest data with summarising properties of these types of scintillators including the mixed ones. Energy transfer processes between Ce$\text{}^{3+}$ main centres and Ce$\text{}^{3+}$ multisites are discussed together with their mechanisms including processes between Ce $\text{}^{3+}$ and Gd$\text{}^{3+}$ ions. Finally, the characteristic properties of scintillating crystals based on perovskite structure are reviewed.
Źródło:
Acta Physica Polonica A; 1996, 90, 1; 45-54
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mixed Valence Quasiparticles in CuO$\text{}_{2}$ Planes
Autorzy:
Bała, J.
Oleś, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/1955491.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Jb
75.30.Ds
75.10.Lp
Opis:
The motion of a single hole doped to a CuO$\text{}_{2}$ plane of a high temperature superconductor is described by a spin-fermion model which treats explicitly the hybridization with the upper Hubbard band. One finds that sectors of Zhang-Rice bound states coexist with reasonably damped oxygen and copper-like quasiparticles, with a considerable transfer of the spectral weight to the upper Hubbard band. The oxygen states have small dispersions and can be identified in the angle-resolved photoemission experiments for Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8}$.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 333-336
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of two-stage magnetic Barkhausen noise measurement method at power line frequency
Autorzy:
Pal'a, J.
Šoka, M.
Powiązania:
https://bibliotekanauki.pl/articles/1070541.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Rs
75.60.Ej
Opis:
The aim of the paper was to study the features of measurement of the magnetic Barkhausen noise by the new two-stage method in the high excitation frequency region (power line frequency). The magnetic Barkhausen noise was investigated on grain oriented Fe-3%Si steel subjected to different heat treatment. By application of an air coil on the output of the power amplifier we were able to linearize the excitation field. At the same time, the air coil suppressed the unwanted noise from the output of the power amplifier. We have found that the two-stage method is able to reveal a peak of the power spectrum even if it is located at low frequency, in contrast to the classical one-stage method. Further, we successfully applied a model of the power spectrum to the real magnetic Barkhausen noise obtained from the two-stage measurement.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 383-387
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

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