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Wyszukujesz frazę "64.60.i" wg kryterium: Temat


Tytuł:
Nonclassical Critical Behaviour and Low Temperature Anomalies in Ferroelectric DMACA as Described by Many-Sublattice Model
Autorzy:
Gałązka, M.
Zieliński, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399033.pdf
Data publikacji:
2013-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.10.+h
64.60.-i
64.60.Cn
Opis:
A model based on the crystallographic data on dimethylammonium nonachlorodiantimonate (DMACA) is constructed. Gradual orientational ordering of three inequivalent sublattices of the dimethylammonium cations is shown to be at the origin of the anomalous behaviour of the spontaneous polarisation in this material. A quantitative comparison with the experimental data reveals a temperature dependence of a coupling between two sublattices and a strong deformability of the underlying structure.
Źródło:
Acta Physica Polonica A; 2013, 124, 6; 1013-1019
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Melting of Two-Dimensional Monolayer Films
Autorzy:
Patrykiejew, A.
Zientarski, T.
Binder, K.
Powiązania:
https://bibliotekanauki.pl/articles/1945440.pdf
Data publikacji:
1996-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.65.-i
64.60.-i
Opis:
The melting of two-dimensional films formed on the (100) fcc crystal is studied by Monte Carlo simulation. The results obtained suggest that in systems with only weakly corrugated surface potential, exhibiting the hexagonal close packed solid structure, the melting transition is followed by the Ising-type transition as predicted by the theory of Nelson and Halperin. In the case of highly corrugated surface potential, the film forms registered structure which disorders gradually as the temperature is raised.
Źródło:
Acta Physica Polonica A; 1996, 89, 5-6; 735-742
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Embedded Atom Method for Theoretical Strength and Stability of Some fcc Metals
Autorzy:
Öztekin Çiftci, Y.
Çolakoğlu, K.
Powiązania:
https://bibliotekanauki.pl/articles/2028900.pdf
Data publikacji:
2001-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
62.20.-x
Opis:
The structural phase transformation and theoretical strength of fcc metals Ni, Cu, Ag, Al, Au, and Pt under [100] uniaxial loading are studied by using analytical embedded-atom-potential method. In the present calculations the stress-free bcc phase is found unstable and fcc phase is found to be stable. The obtained energy differences of fcc-bcc phases are comparable with those found by the first-principles calculations and experiments for all metals considered. The present pair potential in the embedded-atom method is used for the first time for this purpose. Theoretical lattice parameters, volumes, and energies of the bcc and fcc structures for each metal at zero pressure are calculated and compared with the available experimental values. Third-order elastic constants and pressure-volume curves for studied metals are also investigated and found generally good agreement with experiments.
Źródło:
Acta Physica Polonica A; 2001, 100, 4; 539-551
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic Waves Generation in $Ni_{2.14}Mn_{0.81}GaFe_{0.05}$ Heusler Alloy at Structural Phase Transition
Autorzy:
Bychkov, I.
Kuzmin, D.
Kalenov, D.
Kamantsev, A.
Koledov, V.
Kuchin, D.
Shavrov, V.
Powiązania:
https://bibliotekanauki.pl/articles/1387405.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
75.50.Cc
Opis:
Electromagnetic waves generated by the Heusler alloy $Ni_{2.14}Mn_{0.81}GaFe_{0.05}$ at structural phase transition was detected in the frequency range of 28-32 GHz. Influence of the kinetics of phase transitions on the nature of the sample millimeter radiation was studied as well. It has been observed that the contribution of the intrinsic radiation increases with increasing of the heating/cooling rate. The possible mechanisms and theory of such effect is discussed. It is shown that the maximum radiation intensity should be emitted in direction perpendicular to the movement of interphase boundary.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 588-590
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Behaviors of Phase Diagrams of Ising Model with Competing Ternary and Binary Interactions on a Cayley Tree of Arbitrary Order
Autorzy:
Akin, H.
Ganikhodjaev, N.
Uguz, S.
Temir, S.
Powiązania:
https://bibliotekanauki.pl/articles/1490877.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.De
Opis:
An Ising model with competing interactions has recently been studied extensively because of the appearance of nontrivial magnetic orderings. In this paper, we study the phase diagrams for the Ising model on a Cayley tree with competing nearest-neighbor interactions J and ternary prolonged interactions $J_{t_{p}}$ on a Cayley tree of arbitrary order k and compare with the phase diagrams obtained in Uguz et al. and Vannimenus results for the Ising model on a Cayley tree with competing nearest-neighbor interactions J and ternary prolonged interactions $J_{p}$. For some values of k, we obtain phase diagrams of the model. We clarify the role of order k of the Cayley tree. We also plot the variation of the wave vector with temperature.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 104-107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Competing Interactions on a Cayley Tree-Like Lattice: Pentagonal Chandelier
Autorzy:
Uguz, S.
Ganikhodjaev, N.
Akin, H.
Temir, S.
Powiązania:
https://bibliotekanauki.pl/articles/1490904.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.De
Opis:
Different types of lattice spin systems with competing interactions have rich and interesting phase diagrams. In this study we present some new results for such systems involving the Ising spin system (i.e. σ = ± 1) using a generalization of the Cayley tree-like lattice approximation. We study the phase diagrams for the Ising model on a Cayley tree-like lattice, a new lattice type called pentagonal chandelier, with competing nearest-neighbor interactions $J_1$, prolonged next-nearest-neighbor interactions $J_{p}$ and one-level next-nearest-neighbor senary interactions $J_{l_1}^{(6)}$. The colored phase diagrams contain some multicritical Lifshitz points that are at nonzero temperature and many modulated new phases. We also investigate the variation of the wave vector with temperature in the modulated phase and the Lyapunov exponent associated with the trajectory of the system.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 114-118
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature and Pressure Dependence of the Linewidth for an Internal Mode in the Solid Phases of Benzene
Autorzy:
Yurtseven, H.
Şenol, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399290.pdf
Data publikacji:
2013-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
05.70.Fh
Opis:
The pressure dependence of the Raman linewidths for the $ν_1$ breathing mode is analyzed using the experimental data from the literature for the solid phases (I, II, III and III') in benzene. Increase (I, III and III') and decrease (II) in the Raman linewidths are described by a power-law analysis with the critical exponent β. The β values we find, which characterize the phase transition are in favour of the first order among those phases considered in benzene. The temperature and pressure dependence of the frequencies and linewidths of various Raman modes can be analyzed using a power-law formula, as studied here for the solid phases (I, II, III and III') in benzene when the experimental data are available in the literature.
Źródło:
Acta Physica Polonica A; 2013, 124, 4; 698-701
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Transition in Quasi-Two-Dimensional Horizontally Driven Granular System
Autorzy:
Shah, S.
Li, Y.
Khan, W.
Din, N.
Chand, R.
Powiązania:
https://bibliotekanauki.pl/articles/1489921.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Rm
64.60.-i
Opis:
In an experimental setup, consisting of quasi-two-dimensional square cell, the motion of monodisperse spherical steel balls is studied. The cell is vibrated horizontally to eradicate the compaction of balls due to gravity. By raising the number density of the steel balls, the dilute fluid has been gradually alternated into dense fluid. The temperature of granular media, along the driven and transverse directions, has been found to be anisotropic. Transition from granular gas to the liquid-like fluid has been observed. The radial distribution function of the balls in the cell is investigated for the authentication of the structural changes. Furthermore, the fast Fourier transformation for the 2D system is carried out to confirm these changes.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 699-702
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR Study of Monoclinic RbD$\text{}_{2}$PO$\text{}_{4}$ Monocrystal Doped with Cr$\text{}^{5+}$ Ion
Autorzy:
Waplak, S.
Shuvalov, L. A.
Powiązania:
https://bibliotekanauki.pl/articles/1932129.pdf
Data publikacji:
1995-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.-v
64.60.-i
Opis:
Deuterated monoclinic RbD$\text{}_{2}$PO$\text{}_{4}$ (DRDP) doped with chromium Cr$\text{}^{5+}$ is studied by EPR in 90 K to 400 K temperature range. EPR reveals two types of paramagnetic centers: single Cr$\text{}^{5+}$ (S = 1/2) complex and Cr$\text{}^{5+}$-Cr$\text{}^{5+}$ coupled pairs with effective spin S = 1. The EPR line splitting of single Cr$\text{}^{5+}$ complex in DRDP versus temperature agrees with the unit cell multiplication. The splitting of EPR line of pair spectrum appears at T* = 160 K, far below the phase transition temperatures and is due to the anisotropy of the exchange interaction. The clustering effect in the low-dimensional DRDP is suggested.
Źródło:
Acta Physica Polonica A; 1995, 87, 3; 643-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applications of Density Matrix Renormalization Group to Problems in Magnetism
Autorzy:
Gehring, G. A.
Bursill, R. J.
Xiang, T.
Powiązania:
https://bibliotekanauki.pl/articles/1953163.pdf
Data publikacji:
1997-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
11.10.Gh
Opis:
The application of real space renormalization group methods to quantum lattice models has become a topic of great interest following the development of the density matrix renormalization group by White. This method has been used to find the ground and low-lying excited state energies and wave functions of quantum spin models in which the form of the ground state is not clear, for instance because the interactions are frustrated. It has also been applied to fermion problems where the tendency for localization due to the strong Coulomb repulsion is opposed by the lowering of the kinetic energy which occurs as a result of electron transfer. The approach is particularly suitable for one-, or quasi-one-dimensional problems. The method involves truncating the Hilbert space in a systematic and optimised manner. Results for the ground state energy are thus variational bounds. The results for low-lying energies and correlation functions for one-dimensional systems have unprecedented accuracy and the method has become the method of choice for solving one-dimensional quantum spin problems. We review the method and results obtained for the spin-1 chain with biquadratic exchange as well as the spin-1/2 model with competing nearest and next nearest neighbour exchange will be described. More recently, the density matrix renormalization group has been applied to reformulate the coupling constant renormalization group approach which is appropriate for the study of critical properties. This approach has been applied to the anisotropic spin-1/2 Heisenberg chain. Finally, we discuss recent work which has borne promising applications in two dimensions - the Ising model and the two-dimensional Hubbard model.
Źródło:
Acta Physica Polonica A; 1997, 91, 1; 105-119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PIPT from the Beginning to Future
Autorzy:
Cailleau, H.
Luty, T.
Koshihara, S.
Servol, M.
Lorenc, M.
Buron-Le Cointe, M.
Collet, E.
Powiązania:
https://bibliotekanauki.pl/articles/1489952.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
64.70.K-
78.47.D-
Opis:
The birth of the field of photoinduced phase transitions was strongly influenced by the conceptual viewpoint expressed by Professor Y. Toyozawa on the condensation of relaxed excitons. Since this first period, twenty years ago, this young field has been expanding rapidly along a diversity of directions. Nowadays, it goes hand in hand with the challenges of today's science: emergence, nonlinearity, coherence, far away from equilibrium, for example. The control of the functionality of a material via photoexcited states poses many new fundamental questions. Some of them will be overviewed: (i) the nature of the control parameters and the nature of the relevant collective variables, especially the order parameters, which characterize the evolution of the system, (ii) the difference between photoinduced transformations under continuous light irradiation and those resulting from an ultrashort laser pulse, (iii) the physical mechanisms of ultrafast photoinduced phase transitions from the formation and proliferation of phototransformed entities to the softening of a collective mode.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 297-306
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phenomenological Versus Microscopic Interpretation of Incommensurate Systems -BCCD and the ANNNI-Model
Autorzy:
Schaack, G.
Powiązania:
https://bibliotekanauki.pl/articles/1929174.pdf
Data publikacji:
1993-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
64.70.Rh
77.80.Bh
Opis:
Phenomenological and microscopic models to treat modulated crystal structures are reviewed. Their applicability to interpret the specific phase diagram of betaine-calciumchloride-dihydrate (BCCD), which is of the "incomplete devils,s staircase" type, is critically discussed. Some experimental observations, which emphasize the fractal topology of the BCCD phase diagram, have been compiled. They support the preference of microscopic approaches as the ANNNI-model over the classic Landau theory for this specific case.
Źródło:
Acta Physica Polonica A; 1993, 83, 4; 451-462
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rayleigh Scattering of Mössbauer Radiation Method Used in Dynamics Studies of Condensed Matter
Autorzy:
Enescu, S.
Bibicu, I.
Powiązania:
https://bibliotekanauki.pl/articles/2042086.pdf
Data publikacji:
2005-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.45.+x
64.60.-i
64.70.Rh
Opis:
The Rayleigh scatte ring of the Mössbauer radiation is a less common technique used in the study of the properties of condensed matter. The detection of the scattered radiation via the nuclear resonance absorption, with an energy resolution of the order of 10$\text{}^{-8}$ eV makes this technique very sensitive to dynamics changes. The results of our studies by the Rayleigh scattering of the Mössbauer radiation on pyrolytic graphite (C) and rubidium tetrachlorozincate (Rb$\text{}_{2}$ZnCl$\text{}_{4}$) are reported. The contribution of the coherent inelastic scattering to the total intensity in C(002) is presented like a consequence of the coupling motions of C atoms in the hexagonal plane. The normal-incommensurate phase transition in Rb$\text{}_{2}$ZnCl$\text{}_{4}$ is discussed in connection with the photon-phonon interaction.
Źródło:
Acta Physica Polonica A; 2005, 107, 3; 479-489
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Gibbs Measures of the Potts Model with Three Competing Interactions on Cayley Tree of Order 3
Autorzy:
Akin, H.
Saygılı, H.
Powiązania:
https://bibliotekanauki.pl/articles/1186977.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
75.10.Hk
64.60.De
Opis:
In this paper, we consider the Potts model with competing interactions on the Cayley tree of order three. We give the Potts model on the Cayley tree and its recursion relation. We construct the Gibbs states corresponding to the model by using Markov random field method. We calculate the critical curve, such that there is a phase transition for the model. We show that there are phase transition of the model for some given parameters. We extend the results obtained by Akin and Temir (Condensed Matt. Phys. 14, 23003 (2011)).
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 845-848
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Description of Extreme Gibbs Measures for the Ising Model with Three Interactions
Autorzy:
Akin, H.
Ganikhodjaev, N.
Temir, S.
Uguz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1400048.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
64.60.-i
64.60.De
75.10.Hk
Opis:
In this paper, we consider an Ising model with three competing interactions (nearest neighbor, next-nearest neighbor, and ternary prolonged neighbor) on the Cayley tree of order two, investigated by Ganikhodjaev et al. We study translation-invariant Gibbs measures of the Ising model with these competing interactions. Also, we investigate the set of the extreme Gibbs measures called Markov random fields with memory 2 of the model.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 484-487
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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