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Wyświetlanie 1-28 z 28
Tytuł:
Te Shallow Donor Solubility Mechanism in GaAs
Autorzy:
Słupiński, T.
Zielińska-Rohozińska, E.
Harasimowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1952703.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
72.80.Ey
Opis:
Results of thermal annealing of extremely highly doped GaAs:Te on room temperature Hall electron concentration and diffuse X-ray scattering are briefly reported. Reversible decrease/increase in electron concentration vs. temperature of annealing perfectly coincides with a strong increase/decrease in diffuse X-ray scattering intensity. An analysis of X-ray results indicates an arising of correlations in impurity positions in crystal lattice points in GaAs:Te solid solution for very high doping level. We give a sketch of a new formal model of tight bond creation between impurity atoms, which can consistently describe our results. The model is free from difficulties in describing annealing results encountered by a widely spread model of charge compensation by native acceptors.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1080-1084
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Relation of the Order-Parameter and Transition Temperature in Ferroelectric Solid Solutions
Autorzy:
Windsch, W.
Braeter, H.
Powiązania:
https://bibliotekanauki.pl/articles/1931631.pdf
Data publikacji:
1994-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
77.80.Bh
Opis:
Within the framework of the model of coupled anharmonic oscillators a ferroelectric solid solution is described with only a few parameters. In high-temperature approximation a linear relation between the square of the order parameter and the transition temperature is obtained. This is illustrated by an application to several modified lead titanate ceramics, the linear relation between transition temperature and tetragonal lattice deformation is verified. For tris-sarcosine calcium chloride (bromide) (TSCC/B) at very low temperatures the expected deviation from the classical behaviour is seen.
Źródło:
Acta Physica Polonica A; 1994, 86, 3; 393-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small Angle X-Rays Scattering Studies of Biomolecules
Autorzy:
Funari, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/2030570.pdf
Data publikacji:
2002-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
87.80.-y
64.75.+g
Opis:
The building units of biological systems, the biomolecules, cannot easily be organized or even classified into defined categories. They can be as simple as water or complex as tintin, a muscle protein extremely large with several thousand atoms. To understand their function, one must know their characteristics, where they occur and what they do. One approach to reach such an ambitious task is to determine their structure, as single molecules or assembled into aggregates. Small angle X-ray scattering is the most important method for this purpose. We present studies carried out on several systems, and aiming at different questions about them. We start with lipids, the main components of the cell membranes. These membranes form the cell boundaries, the moiety required for the so-called membrane proteins, but also influence significantly several aspects of biological activity. More complex systems like a muscle fibre is also presented, showing that changes in the structure are related to the movement mechanism. It becomes easy to conclude that knowing the structures and the changes occurring in them is an important way to understand the function of biomolecules and therefore their role in the life cycle.
Źródło:
Acta Physica Polonica A; 2002, 101, 5; 647-658
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of the Unstable Mixing Region in $Zn_{1-x}Cd_xO$ Ternary Alloys
Autorzy:
Shtepliuk, I.
Powiązania:
https://bibliotekanauki.pl/articles/1399136.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.-g
81.30.-t
81.30.Bx
Opis:
The $Zn_{1-x}Cd_xO$ ternary alloys with a narrow band gap, which are useful for light emitters in the visible wavelengths, are studied with respect to the unsteady region in mixing. This unstable region in mixing is calculated from the free energy of mixing using the strictly regular solution model. The interaction parameter used in this calculation is obtained by means of the valence-force-field model. An influence of the strain energy induced by substrate on the region of the spinodal decomposition for the $Zn_{1-x}Cd_xO$ system is studied and discussed.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 865-868
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Size Distribution of Guinier-Preston Zones in Al-Ag Alloys by Small-Angle X-ray Scattering Method
Autorzy:
Bierska, B.
Pająk, L.
Powiązania:
https://bibliotekanauki.pl/articles/2035487.pdf
Data publikacji:
2002-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.Eq
81.40.Cd
64.75.+g
Opis:
Small-angle X-ray scattering method recognised to be very useful in the studies of structural problems of materials inhomogeneous in nanoscale. Studies by small-angle X-ray scattering on the Al-Ag alloys are presented. The size distributions of spherical Guinier-Preston zones were calculated using Vonk's and Glatter's methods. Small-angle X-ray scattering studies were performed on Al-5.0 at.%Ag alloy containing spherical Guinier-Preston zones in theη-state. For this alloy one can assume that scattering particles are of spherical shape, have uniform electron density and scatter independently. Moreover, the size distributions were calculated for Al-1.6 at.%Ag alloy containing Guinier-Preston zones in ε-state (scattering particles with not uniform electron density). Both, Vonk's and Glatter's, methods gave similar size distributions. Profiles of size distributions for Guinier-Preston zones inε-state are more complex in comparison to Guinier-Preston zones inη-state. It is connected with a complex structure of Guinier-Preston zones in ε-state. A modification of the structure model of Guinier-Preston zones inε-state is proposed.
Źródło:
Acta Physica Polonica A; 2002, 102, 2; 227-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Casimir Force between Nanoparticles Immersed in a Crosslinked Polymer Blend
Autorzy:
El Fassi, S.
Benhamou, M.
Boughou, M.
Kaidi, H.
El Yaznasni, M.
Ridouane, H.
Powiązania:
https://bibliotekanauki.pl/articles/1535673.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.25.Hq
64.75.+g
82.70.Gg
Opis:
We consider a crosslinked polymer blend made of two polymers of different chemical nature. We suppose that such a system incorporates small colloidal particles, which prefer to be attracted by one polymer, close to the spinodal temperature. This is the so-called critical adsorption. As assumption, the particle diameter, $d_0$, is considered to be small enough in comparison with the size of microdomains (mesh size) ξ* ~ $an^{1//2}$, with a - the monomer size and n - the number of monomers between consecutive crosslinks. The critical fluctuations of the crosslinked polymer mixture induce a pair-potential between particles located in the non-preferred phase. The purpose is the determination of the Casimir pair-potential, $U_2 (r)$, as a function of the interparticle distance r. To achieve calculations, use is made of an extended de Gennes field theory that takes into account the colloid-polymer interactions. Within the framework of this theory, we first show that the pair-particle is attractive. Second, we find for this potential the exact form: $U_2(r)//k_{B}T = - A_{H}(d_0//r)^2 exp(-r//ξ*) - B_{H}(d_0//r)^4 exp(-2r//ξ*)$, with the known universal amplitudes $A_{H}$ > 0 and $B_{H}$ > 0 (the Hamaker constants). This expression clearly shows that the pair-potential differs from its homologue with no crosslinks only by the two exponential factors exp(-r/ξ*) and exp(-2r/ξ*). The main conclusion is that the presence of reticulations reduces substantially the Casimir effect in crosslinked polymer blends.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 606-612
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoelectron Emission Microscopy and its Application to the Study of Polymer Surfaces
Autorzy:
Cossy-Favre, A.
Diaz, J.
Anders, S.
Padmore, H.
Liu, Y.
Samant, M.
Stöhr, J.
Brown, H.
Russell, T. P.
Powiązania:
https://bibliotekanauki.pl/articles/1964108.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.Ms
73.61.Ph
64.75.+g
Opis:
The X-ray photoelectron emission microscopy at the Advanced Light Source has a spatial resolution of 0.2 microns at an accelerating voltage of 12 kV. The tunability of the photon energy is used to provide chemical state information using near edge X-ray absorption fine structure spectroscopy on the sub-micrometer scale. The homogeneity of thin films of polymer blends was studied for various film thicknesses. The polystyrene/polyvinylmethylether film of 194 Å showed protrusions of 2-3 μm diameter with an enriched polystyrene content while the polystyrene/polystyreneacrylonitrile 504 Å thick films showed 5-6 μm segregated regions without any topological structure.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 923-927
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Copper Deficiency - a Crystallochemical Nature of Ce-Doped Gd$\text{}_{2}$CuO$\text{}_{4}$ Phase. Part II
Autorzy:
Horyń, R.
Bukowska, E.
Sikora, A.
Wołcyrz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2041471.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
Two samples of nominal composition Gd$\text{}_{1.80}$Ce$\text{}_{0.15}$CuO$\text{}_{4.0}$ and Gd$\text{}_{1.85}$Ce$\text{}_{0.15}$CuO$\text{}_{4.075}$ were subjected for a long-term treatment in air at 1100°C, comprised with a precise control of their weights vs. time of the treatment applied. The gravimetric analysis and the iodometric titration, both showed a deficiency on Cu-site, steadily increasing vs. time with a slight tendency to a saturation. The X-ray analysis of the resulting products showed that even after 272 h of sintering, the samples remained single phase of the "214" structure type. Refinement of their crystal structures as well as density measurements, both allowed confirming Cu deficient structure constitution of these samples. Results of dc-magnetization measurements, performed prior to reduction of the sample's overall oxygen content, did not show any sign of superconductivity down to 4.2 K. These preliminary results indicate that copper deficiency, developing during synthesis, may occur to be a decisive factor for the reported lack of superconductivity in Ce-doped Gd$\text{}_{2}$CuO$\text{}_{4}$ phase. Oxygen content reduction and further tests on the samples obtained are in progress.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 733-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Relations in Gd$\text{}_{2}$O$\text{}_{3}$-CeO$\text{}_{2}$-CuO System at 980°C. Part I
Autorzy:
Horyń, R.
Sikora, A.
Bukowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2041467.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
Phase equilibria in Gd$\text{}_{2}$O$\text{}_{3}$-CeO$\text{}_{2}$-CuO system were studied based on samples obtained from appropriate mixtures of the starting components, prepared by a conventional solid state reaction in air. The phase relations prevalent in this system have been deduced based on X-ray diffraction of well-equilibrated samples. An isothermal cross-section diagram through the system at 980°C is presented and chemical constitution of the Ce-doped Gd$\text{}_{2}$CuO$\text{}_{4}$ phase is proposed.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 727-731
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Small-Angle Scattering of Synchrotron Radiation for Studying Solid State and Biological Systems
Autorzy:
Fratzl, P.
Powiązania:
https://bibliotekanauki.pl/articles/1920835.pdf
Data publikacji:
1992-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.Lx
64.75.+g
81.30.Mh
87.22.Bt
Opis:
The principles of small-angle X-ray scattering are briefly reviewed with emphasis on the particular advantages of the use of synchrotron radiation. The application of the technique is illustrated by several examples concerning precipitates in alloys, internal oxidation, porous materials, as well as the structure of bone.
Źródło:
Acta Physica Polonica A; 1992, 82, 1; 121-136
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase and Structural Study of Self-Doped La$\text{}_{1-x-y}$Ca$\text{}_{x}$Ø$\text{}_{y}$MnO$\text{}_{3+δ}$
Autorzy:
Figueiras, F.
Araújo, J. P.
Amaral, V. S.
Tavares, P. B.
Lopes, A. B.
Vieira, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2037125.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.75.+g
81.40.Rs
75.50.-y
72.20.My
Opis:
To understand the combined effect of divalent ion and A-site vacancy (Ø) self-doping, beyond the binary La$\text{}_{1-x}$MnO$\text{}_{3}$ system, polycrystalline La$\text{}_{1-x-y}$Ca$\text{}_{x}$Ø$\text{}_{y}$MnO$\text{}_{3+δ}$ samples were studied. Samples with Ca substitution and excess Mn in the range x<0.33 and y<0.45, respectively, were prepared by standard solid-state reactions. Structural and phase analysis of the samples were done by X-ray diffraction and transmission electron microscopy. The manganite structure in this composition range includes rhombic and orthorhombic phases. Most samples contain the hausmanite phase (Mn$\text{}_{3}$O$\text{}_{4}$) coexisting with the manganite phase. A small amount of perovskite related AMn$\text{}_{7}$O$\text{}_{12}$ (A=La,Ca) structure near the hausmanite-manganite boundary is also found in samples treated in oxygen atmosphere. The calculated vacancy content accommodated in the manganite phase can be higher than 1/8, the reported limit for La$\text{}_{1-x}$MnO$\text{}_{3}$, which is confirmed in our x=0 sample. For the compositions studied, a ferromagnetic metallic behavior below T$\text{}_{C}$ is found, confirming the stability of the Mn sublattice, and near the optimum stoichiometric ((x=0. 33, y=0) system, a net A-site vacancy content (up to y=0.2) does not degrade the magnetic and electric properties.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 173-182
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SrLaGaO$\text{}_{4}$-SrLaAlO$\text{}_{4}$ Solid Solutions - Substrate Materials with Tuneable Lattice Parameter for Various HTSC Compounds
Autorzy:
Berkowski, M.
Fink-Finowicki, J.
Mojaiskaia, E.
Powiązania:
https://bibliotekanauki.pl/articles/1964363.pdf
Data publikacji:
1997-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.-d
81.10.Fq
61.50.Νw
64.75.+g
Opis:
The increase in Τ$\text{}_{c}$ for high temperature superconductors can be realized, among others, by appropriate substrate/film combinations. SrLaGaO$\text{}_{4}$-SrLaΑlO$\text{}_{4}$ solid solutions were grown by the Czochralski method. The already achieved results allow to obtain single crystals of SrLaΑl$\text{}_{1-x}$Ga$\text{}_{x}$O$\text{}_{4}$ with lattice constant a in the range from 0.3754 to 0.3775 nm, and SrLaGa$\text{}_{1-x}$Αl$\text{}_{x}$O$\text{}_{4}$ crystals with lattice constant a in the range from 0.3843 to 0.3826 nm. Electron-probe microanalysis along obtained single crystals was used for determination of segregation coefficient between aluminum and gallium ions.
Źródło:
Acta Physica Polonica A; 1997, 92, 1; 182-186
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Optical Characterisation of Hydrogenated Soda-Lime Silicate Glasses Doped with Silver and Copper
Autorzy:
Suszyńska, M.
Krajczyk, L.
Macalik, B.
Powiązania:
https://bibliotekanauki.pl/articles/2037038.pdf
Data publikacji:
2003-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Fs
64.75.+g
68.37.Lp
78.20.-e
78.40.Ha
Opis:
The results of comparative studies of the effect of hydrogenation upon structural and optical properties of the commercial soda-lime silicate glasses doped either with monovalent silver or copper have been presented. The samples were characterised by means of the scanning and transmission electron microscopy and the UV-VIS-IR absorption spectroscopy. It has been shown that the annealing of suitably ion-exchanged specimens in gaseous hydrogen atmosphere could be considered as an effective procedure for obtaining composite materials of expected properties correlated with the induced changes of the morphology of both the glassy matrix and the dopant.
Źródło:
Acta Physica Polonica A; 2003, 104, 6; 559-569
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Requirement for and Use of Coated P92 Steel for Enhanced Structural Integrity at High Temperature
Autorzy:
Hoey, T.
Chen, R.
McCartney, D.
Sun, W.
Mansfield, J.
Barnard, P.
Foster, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402066.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.15.Pq
68.37.-d
61.05.-a
64.75.-g
Opis:
To achieve climate change targets and to improve the efficiency of fossil fuel power plant the temperature and pressure of operation must be increased. With steam temperatures predicted to rise by 50-100 K in the next 30 years, this presents a number of material challenges, not least for the ferritic steels used for steam pipework. Currently the best in class ferritic steel for power plant steam pipework is P92, a 9-12% Cr advanced martensitic steel that was developed for its superior high temperature creep resistance. This paper will give a brief overview of P92 microstructure, composition and metallurgy and identify experimentally and computationally some key features of the material. As well as failure by creep, P92 at high temperature also suffers from steam oxidation damage. Recent literature suggests that coatings applied to P92 are a very promising solution. A short review of previous work on steam oxidation resistant coatings for P92 is included. A novel Co-Cr-C coating that has not previously been explored for this application is described. Experimental and computational characterisation is included.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 514-519
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Phase Decomposition on Magnetic Structure of $Cu_{0.4}Mn_{0.3}Ni_{0.3}$ Alloy
Autorzy:
Świderska, K.
Jankowska-Kisielińska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1385743.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.F-
64.75.-g
75.40.-s
75.47.Np
75.50.Ee
81.40.Rs
Opis:
The purpose of present investigation was to study the effects of phase decomposition of the $Cu_{0.4}Mn_{0.3}Ni_{0.3}$ alloy on its magnetic ordering. The single-crystal sample was examined by elastic neutron scattering before and after five subsequent annealing runs. The results indicate that in small fraction of the quenched sample volume there are two types of antiferromagnetic order: one of them AF1 of the long range, the other one of the short range. Ageing induces phase decomposition which yields disappearance of AF1 long range order and increase of the volume of new ordered phase. The results of the investigations of the aged sample indicate that regions of new tetragonal phase exhibit antiferromagnetic ordering with magnetic moments of Mn atoms arranged as in the pure compound MnNi but with unequal domain distribution. The intensity of magnetic component of super-structure reflections increases with the duration of ageing at lower rate than component due to atomic order.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 394-396
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective Field Methods for Magnetic Systems
Autorzy:
Kamieniarz, G.
Dekeyser, R.
Musiał, G.
Powiązania:
https://bibliotekanauki.pl/articles/1930600.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.Cn
64.60.Fr
05.50.+q
75.10.Dg
75.10.Hk
75.10.Jm
75.40.Cx
75.40.Mg
Opis:
The self-consistency conditions inherent in the mean-field approximation are extended to take into account some pair correlations. Ii is shown that this extension is systematically improvable and applicable to the spin systems with short-range interactions in the entire temperature region. With two correlations included and the renormalization-group ideas implemented, the critical properties of the Ising model are satisfactorily revealed. Moreover, the improved estimates of the thermodynamical quantities for the quantum linear XY model from the finite-size calculations are found down to very low temperatures.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 413-417
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Test of Molecular-Field Renormalization Group
Autorzy:
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1964785.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Mg
75.10.Im
64.60.Ak
Opis:
A new transfer matrix approach has been worked out to test the predictions of the molecular-field renormalization group for square Ising clusters with a linear size up to L ≤ 11. The convergence of the finite-size critical couplings towards the exact value for the molecular-field renormalization group is shown and the limit of the ratio y$\text{}_{h}$/y$\text{}_{t}$ consistent with the corresponding universal value is revealed.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 423-426
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Miscibility of Perylene Derivatives with Fatty Acid in Two-Dimensional Binary Mixture
Autorzy:
Makowiecki, J.
Martynski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1203963.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.18.-g
68.47.Pe
64.75.Jk
64.75.St
Opis:
Two component mixtures of a fluorescent perylene dye (derivative of 3,4,9,10-perylenetetracarboxylic acid) with arachidic acid in the whole range of mole fraction have been investigated in form of molecular monolayers at the air-water interface at different pH of the water subphase. Miscibility of the components in the Langmuir monolayers have been examined for pH 3 and pH 13 of the subphase. Using the Langmuir-Blodgett technique the monolayers were transferred onto freshly cleaved mica sheets and morphology of the films was analyzed using atomic force microscopy working in tapping mode. Investigation of the components miscibility in monolayers, determined by mean molecular area and surface pressure analysis reveals different behavior of the mixtures depending on pH of the subphase. Atomic force microscopy morphology images of the Langmuir-Blodgett films strongly support conclusion about the components mixing and coverage of the mica surface. It has been found that onto acidic subphases components are only miscible in vestigial form, whereas on alkaline the miscibility is strongly affected by the dye concentration.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 757-762
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Effects and Critical Behavior in Low-Dimensional Spin-1/2 Systems
Autorzy:
Kamieniarz, G.
Musial, G.
Dębski, L.
Bieliński, M.
Dekeyser, R.
Powiązania:
https://bibliotekanauki.pl/articles/1964803.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Mg
64.60.-i
75.10.Hk
75.10.Jm
Opis:
The critical coupling and spontaneous magnetization curve for the 2D-Ising model are calculated using the effective-field method with correlations. An application of the method to the quantum S=1/2 1D-Heisenberg model is presented and reliable low-temperature estimates of the specific heat are evaluated.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 445-447
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of the 3D Ising Model at Criticality
Autorzy:
Blöte, H. W. J.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1930588.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.Fr
75.40.Mg
64.60.Ak
Opis:
We present some new finite-size results for the Binder cumulant that we obtained by means of a transfer-matrix perturbation expansion and by the cluster Monte Carlo methods - the Swendsen-Wang and Wolff algorithms and the largest-cluster method. A finite-size scaling analysis taking into account a correction to scaling locates the critical coupling at Kc = 0.221649(4).
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 395-398
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Behaviour of Some 2D Lattice Models
Autorzy:
Kamieniarz, G.
Blöte, H. W.J.
Dekeyser, R.
Powiązania:
https://bibliotekanauki.pl/articles/1930586.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.Cn
64.60.Ak
64.60.Fr
75.40.Mg
Opis:
The density series of the non-interacting hard-square lattice gas model are reanalyzed by the ratio, Dlog Padé and differential approximant methods. The problem of poor consistency between series and other results is resolved. Transfer matrix calculations are performed, implementing both finite-size scaling and conformal invariance. Very accurate estimates of the critical exponents y$\text{}_{t}$, and y$\text{}_{h}$ are obtained in agreement with Ising universality. Furthermore, an improvement of the value of the critical density ρ$\text{}_{c}$ is found. In addition, the universal critical-point ratios of the square of the second and the fourth moment of the magnetization for ferromagnetic Ising models on the square and on the triangular lattice with periodic boundary conditions are reported.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 389-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved Phase Diagrams of Ashkin-Teller Model
Autorzy:
Pawlicki, P.
Kamieniarz, G.
Kozlowski, P.
Dekeyser, R.
Rogiers, J.
Powiązania:
https://bibliotekanauki.pl/articles/1964805.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Mg
75.10.Hk
64.60.Ak
Opis:
The phase diagram of the Askhin-Teller model in two dimensions is determined. Numerical calculations are performed for the simple square L × L lattice using transfer matrix technique. Exploiting finite-size scaling all unknown critical lines were obtained with good accuracy. An extended version of the Ashkin-Teller model is also considered within the molecular field renormalization group method and the critical surface for three-parameter odd-parity Hamiltonian is calculated.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 453-456
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo Study of Phase Separation in Magnetic Insulators
Autorzy:
Murawski, S.
Kapcia, K.
Pawłowski, G.
Robaszkiewicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1385243.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
75.10.-b
75.30.Fv
64.75.Gh
71.10.Hf
Opis:
In this work we focus on the study of phase separation in the zero-bandwidth extended Hubbard with nearest-neighbors intersite Ising-like magnetic interactions J and on-site Coulomb interactions U. The system has been analyzed by means of the Monte Carlo simulations (in the grand canonical ensemble) on two-dimensional square lattice (with N = L × L = 400 sites) and the results for U/(4J) = 2 as a function of chemical potential and electron concentration have been obtained. Depending on the values of interaction parameters the system exhibits homogeneous (anti-)ferromagnetic or non-ordered phase as well as phase separation state. Transitions between homogeneous phases (i.e. antiferromagnetic-non-ordered transitions) can be of first or second order and the tricritical point is also present on the phase diagrams. The electron compressibility K is an indicator of the phase separation and that quantity is of particular interest of this paper.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 281-283
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Direct Simulations of the Quantum Model for CsNiF$\text{}_{3}$
Autorzy:
Caramico D'Auria, A.
Esposito, F.
Esposito, U.
Kamieniarz, G.
Dekeyser, R.
Powiązania:
https://bibliotekanauki.pl/articles/1930597.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.Cn
75.10.Dg
75.10.Jm
75.40.Cx
75.40.Mg
Opis:
We address the problem of reliability of a finite-chain technique for CsNiF$\text{}_{3}$. We investigate the effect of the boundary conditions, completely neglected so far, and apply a new extrapolation procedure appropriate for quantities showing non-monotonic behaviour. From a detailed analysis of the specific heat existing theoretical estimates for the model parameters are discriminated and a strong evidence for the reliability of the direct finite-chain technique predictions is presented.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 409-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulations of Linear S=1 Ferro- and Antiferromagnets
Autorzy:
Kamieniarz, G.
Matysiak, R.
Caramico D'Auria, A.
Esposito, F.
Esposito, U.
Powiązania:
https://bibliotekanauki.pl/articles/1964696.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
75.10.Hk
75.40.Mg
Opis:
The finite-temperature static properties of the spin S=1 antiferromagnetic Heisenberg chains are extensively simulated using the quantum transfer matrix method. The zero-field susceptibility and specific heat as well as the field-dependent magnetization data are evaluated to select the microscopic parameters of a number of real quasi-one-dimensional compounds and to verify some theoretical approaches.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 387-389
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Properties of Two-Dimensional Extended Repulsive Hubbard Model with Intersite Magnetic Interactions - A Monte Carlo Study
Autorzy:
Murawski, S.
Kapcia, K.
Pawłowski, G.
Robaszkiewicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1374074.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
75.10.-b
75.30.Fv
64.75.Gh
71.10.Hf
Opis:
In this paper the two-dimensional extended Hubbard model with intersite magnetic Ising-like interaction in the atomic limit is analyzed by means of the classical Monte Carlo method in the grand canonical ensemble. Such an effective simple model could describe behavior of insulating (anti)ferromagnets. In the model considered the Coulomb interaction (U) is on-site and the magnetic interactions in z-direction (J>0, antiferromagnetic) are restricted to nearest-neighbors. Simulations of the model have been performed on a square lattice consisting of N=L× L=400 sites (L=20) in order to obtain the full phase diagram for U/(4J)=1. Results obtained for on-site repulsion (U>0) show that, apart from homogeneous non-ordered (NO) and ordered magnetic (antiferromagnetic, AF) phases, there is also a region of phase separation (PS: AF/NO) occurrence. We present a phase diagram as well as some thermodynamic properties of the model for the case of U/(4J)=1 (and arbitrary chemical potential and arbitrary electron concentration). The AF-NO transition can be second-order as well as first-order and the tricritical point occurs on the diagram.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-110-A-114
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Behaviour of the Mean-Field Ferromagnet $Cu_{1.02}[Cr_{1.77}Ti_{0.24}]Se_4$
Autorzy:
Krok-Kowalski, J.
Władarz, G.
Rduch, P.
Malicka, E.
Groń, T.
Guzik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1409626.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.50.Dd
64.60.Ht
Opis:
Magnetization, M, and susceptibility, χ, measurements showed both strong lowering of magnetic moment in comparison with $CuCr_2Se_4$ matrix and zero-field-cooling-field-cooling susceptibility splitting characteristic for the spin-glass behaviour. Isothermal magnetization curves, M(H), easy saturate and large values both of the Curie $T_{C}$=253 K and Curie-Weiss θ=283.5 K temperatures indicate the ferromagnetic order which coexists with the spin-glass state. The critical behaviour investigated around the paramagnetic-ferromagnetic phase transition revealed that the values of critical exponents are close to those predicted by the mean field model for long-range magnetic interactions.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1102-1104
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Phase Diagram of the Zero-Bandwidth Extended Hubbard Model with Intersite Magnetic Interactions for Strong On-Site Repulsion Limit
Autorzy:
Murawski, S.
Kapcia, K.
Pawłowski, G.
Robaszkiewicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1426734.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
75.30.Fv
64.75.Gh
71.10.Hf
Opis:
In this report we have analyzed a simple effective model for a description of magnetically ordered insulators. The Hamiltonian considered consists of the effective on-site interaction (U) and the intersite Ising-like magnetic exchange interaction (J) between nearest neighbors. For the first time the phase diagrams of this model have been determined within Monte Carlo simulation on 2D-square lattice. They have been compared with results obtained within variational approach, which treats the on-site term exactly and the intersite interactions within mean-field approximation. We show within both approaches that, depending on the values of interaction parameters and the electron concentration, the system can exhibit not only homogeneous phases: (anti-)ferromagnetic (F) and nonordered (NO), but also phase separated states (PS: F-NO).
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1035-1037
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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