Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Cx" wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-14 z 14
    Tytuł:
    The Energy Spectrum and Thermodynamics of Spin-1/2 XX Chain with Ising Impurities
    Autorzy:
    Ezerskaya, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/1032134.pdf
    Data publikacji:
    2017-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.40.Cx
    Opis:
    The energy spectrum and peculiarities of field and temperature dependences of the basic thermodynamic characteristics of the finite spin-1/2 XX chain closed by one zz (Ising) bond and open ends XX-chain with two zz-impurities at the both ends have been investigated.
    Źródło:
    Acta Physica Polonica A; 2017, 131, 4; 928-930
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zero Temperature Magnetic Frustration in Nona-Membered s=3/2 Spin Rings with Bond Defect
    Autorzy:
    Antkowiak, M.
    Kozłowski, P.
    Kamieniarz, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1427128.pdf
    Data publikacji:
    2012-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.40.Cx
    75.10.Jm
    Opis:
    Zero-temperature limits of the local and global thermodynamic quantities in the nine-membered antiferromagnetic s=3/2 spin ring are investigated by means of numerical exact diagonalization. An anisotropic Heisenberg model with tunable bond defect reflecting continuously varying topology (from closed to open ring) is exploited. The frustrated and non-frustrated phases are identified in the ground-state phase diagram determined by a bond-defect strength and magnetic field. Near the phase boundaries significance of the thermal fluctuations affecting the estimates of the local magnetic quantities found earlier at T=1 K is revealed. For the global quantities the effects of thermal fluctuations are found much weaker. A sequence of the local magnetic moments is analysed and their experimental verification at the edges of the non-frustrated and within the entire frustrated phase is suggested at sufficiently low temperature.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 5-6; 1102-1104
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    New S=1/2 Alternating Chain Compound - High Pressure Form of (VO)$\text{}_{2}$P$\text{}_{2}$O$\text{}_{7^{-}}$
    Autorzy:
    Azuma, M.
    Saito, T.
    Hiroi, Z.
    Takano, M.
    Narumi, Y.
    Kindo, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/2012882.pdf
    Data publikacji:
    2000-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.40.Cx
    75.50.Ee
    Opis:
    The high-pressure phase of (VO)$\text{}_{2}$P$\text{}_{2}$O$\text{}_{7}$ comprises a unique kind of spin-1/2 Heisenberg alternating antiferromagnetic chain, in contrast with the ambient pressure phase containing two crystallographically different chains. Magnetic susceptibility and high-field magnetization data showed the presence of a single spin gap of 23 (magnetization) ~27 (susceptibility) K, not double as observed for the ambient pressure phase. This result shows that the two kinds of chains of the ambient pressure phase have single, different spin gaps.
    Źródło:
    Acta Physica Polonica A; 2000, 97, 1; 205-208
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Towards Spin-Wave Like Approach to the J-J Heisenberg Antiferromagnet in Terms of Composite Spins
    Autorzy:
    Grzybowski, P.
    Chhajlany, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1810417.pdf
    Data publikacji:
    2009-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.50.Ee
    75.40.Cx
    Opis:
    Conventional spin-wave approach relies on an expansion around a relevant classical (unentangled) ground state or equivalently the ground state in the mean field approximation for the quantum model. However, for systems which may admit valence bond ground states, such as the staggered J-J' Heisenberg antiferromagnet, single site mean field approximation is obviously an incorrect zeroth order approximation. In this paper, we introduce a mean field approximation for clusters consisting of two spins connected by a strong bond in the aforementioned model. We identify the quantum critical point and calculate the ground state magnetization within this cluster mean field approximation in one and two dimensions. Finally, we derive an effective dimer Hamiltonian, in the standard basis operator formalism, which may be a basis for further spin-wave like expansions around the cluster mean field approximation ground state.
    Źródło:
    Acta Physica Polonica A; 2009, 115, 1; 168-170
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Susceptibility Behaviour of CuGeO$\text{}_{3}$: Comparison between Experiment and the Quantum Transfer Matrix Approach
    Autorzy:
    Bieliński, M.
    Renard, J.-P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2013702.pdf
    Data publikacji:
    2000-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.40.Cx
    75.40.Mg
    Opis:
    Thermodynamical properties of one-dimensional S=1/2 Heisenberg model with dimerized nearest- and uniform next-nearest-neighbour interactions are studied by the numerically exact quantum transfer matrix method and the results are applied to CuGeO$\text{}_{3}$. Suzuki-Trotter formula is used to obtain a classical system with spin σ=3/2 and effective interactions between nearest-neigbours only. Magnetic susceptibility curve is calculated and compared with new experimental results performed in a wide temperature range, revealing the presence of frustration in the model proposed for CuGeO$\text{}_{3}$.
    Źródło:
    Acta Physica Polonica A; 2000, 97, 5; 851-854
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transfer-Matrix Simulations of Linear Magnetic Systems
    Autorzy:
    Matysiak, R.
    Caramico D'Auria, A.
    Esposito, F.
    Esposito, U.
    Powiązania:
    https://bibliotekanauki.pl/articles/2013975.pdf
    Data publikacji:
    2000-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.40.Cx
    75.40.Mg
    Opis:
    The quantum transfer-matrix method was applied to study the finite-temperature static properties of the spin S=1 antiferromagnetic Heisenberg chains in a wide range of the single-ion anisotropy and temperatures. The high-resolution quantum transfer-matrix simulation data are obtained for the zero-field susceptibility, specific heat as well as for the field-dependent magnetization. The microscopic parameters of a number of real quasi-one-dimensional compounds are found from fitting procedures, some theoretical approaches are numerically verified and an extension of the technique to a non-uniform bond alternating molecular magnets is also put forward.
    Źródło:
    Acta Physica Polonica A; 2000, 97, 5; 959-962
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Some Mesoscopic Rings: Exact Simulations and Experiment
    Autorzy:
    Kamieniarz, G.
    Matysiak, R.
    Caramico D'Auria, A.
    Esposito, F.
    Benelli, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/2014557.pdf
    Data publikacji:
    2000-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.40.Mg
    75.40.Cx
    75.10.Jm
    Opis:
    A numerical transfer-matrix approach and an exact diagonalization technique exploiting the point-group symmetry are worked out in the framework of quantum statistical mechanics and group theory for finite rings. They are applied to spin models of the high nuclearity cyclic clusters [Mn(hfac)$\text{}_{2}$NITPh]$\text{}_{6}$ and Ni$\text{}_{12}$(O$\text{}_{2}$CMe)$\text{}_{12}$(chp)$\text{}_{12}$(H$\text{}_{2}$O)$\text{}_{6}$(THF)$\text{}_{6}$. The microscopic parameters of both molecules (J/k$\text{}_{B}$=350±10 K and J/k$\text{}_{B}$=8.5 K±0.5, g=2.23±0.01, respectively) are then obtained from a fit of the theoretical susceptibility curves to the experimental results which are supplemented for Ni$\text{}_{12}$ by new low-temperature measurements.
    Źródło:
    Acta Physica Polonica A; 2000, 98, 6; 721-727
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal Entanglement and Quantum Non-Locality along the Stepwise Magnetization Curve of the Spin-1/2 Ising-Heisenberg Trimerized Chain
    Autorzy:
    Strečka, J.
    Pavličko, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1032512.pdf
    Data publikacji:
    2017-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Pq
    75.10.Jm
    75.40.Cx
    75.60.Ej
    Opis:
    The spin-1/2 Ising-Heisenberg trimerized chain in a magnetic field is revisited with the aim to explore the quantum entanglement and non-locality within the exactly solved spin system, which exhibits in a low-temperature magnetization curve two intermediate plateaux at zero and one-third of the saturation magnetization. The ground-state phase diagram involves two quantum (antiferromagnetic, ferrimagnetic I) and two classical (ferrimagnetic II, saturated paramagnetic) phases. We have rigorously calculated the concurrence and Bell function in order to quantify the quantum entanglement and non-locality at zero as well as non-zero temperatures. It is demonstrated that the entanglement can be thermally induced also above the classical ground states unlike the quantum non-locality, which means that the thermal entanglement is indispensable for a violation of the locality principle.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 1; 167-169
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Field-Dependent Specific Heat and Energy Gap in the $Yb_4As_3$ Compound
    Autorzy:
    Matysiak, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1534925.pdf
    Data publikacji:
    2010-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.40.Cx
    75.40.Mg
    71.55.Ak
    Opis:
    We report the low-temperature specific-heat simulation results and reanalyzed measurement data on polydomain $Yb_4As_3$ in magnetic fields B = 0 and 6 T. The data considered here are independent and supplement those considered earlier. A quantitative agreement has again been achieved between the magnetic experimental specific-heat data and the numerical results obtained by the quantum transfer-matrix simulation technique, yielding a new evidence in favour of the Heisenberg model of the antiferromagnetic spin S = 1/2 chain with the value of the exchange integral $J//k_{B}$ = - 28 K. The finite-size quantum transfer matrix approximants have been extrapolated exploiting the procedure developed previously. On the basis of the data in magnetic field and using the corresponding density-matrix renormalization group results, the energy-gap size Δ has been estimated for the applied magnetic field B = 6 T, leading to the experimental verification in the extended region of the scaling law Δ ∿ $B^{2//3}$ following from the sine-Gordon model.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 5; 969-970
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Low-Temperature Thermodynamics of Spin-1/2 Orthogonal-Dimer Chain with Ising and Heisenberg Interactions
    Autorzy:
    Verkholyak, T.
    Strečka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1199501.pdf
    Data publikacji:
    2014-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.10.Pq
    75.30.Gw
    75.40.Cx
    Opis:
    We consider an exactly solvable version of the quantum spin-1/2 orthogonal-dimer chain with the Heisenberg intra-dimer and Ising inter-dimer couplings. The investigated quantum spin system exhibits at zero temperature fractional plateaux at 1/4 and 1/2 of the saturation magnetization and it has a highly degenerate ground state at critical fields where the magnetization jumps. We study the field dependence of the specific heat at low temperature. The lattice-gas description is formulated in a vicinity of critical fields to explain the low-temperature behaviour of specific heat.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 1; 22-23
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Anisotropy, Geometric Structure and Frustration Effects in Molecule-Based Nanomagnets
    Autorzy:
    Kamieniarz, G.
    Kozłowski, P.
    Antkowiak, M.
    Sobczak, P.
    Ślusarski, T.
    Tomecka, D.
    Barasiński, A.
    Brzostowski, B.
    Drzewiński, A.
    Bieńko, A.
    Mroziński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1426672.pdf
    Data publikacji:
    2012-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.Xx
    75.10.Jm
    75.10.Pq
    75.40.Cx
    Opis:
    In this paper we review our results of comprehensive study of molecular nanomagnets recently synthesized in the form of the chromium-based molecules and bimetallic copper-containing chains as well as we present some new findings. We focus on effects of anisotropy, geometry and frustration appearing in various thermodynamic properties of the nanoscale magnets which are described by Heisenberg-like spin models and simulated by accurate numerical methods. We show that bond-dependent exchange anisotropy is needed to model magnetic torque in the Cd-doped chromium ring. We argue that only in the limit of infinite rings (n → ∞) frustration can be considered as the opposite to bipartiteness in the odd numbered (3 ≤ n ≤ 9) s = 3/2 quantum spin rings. We analyse the influence of exchange interactions and anisotropy on magnetic susceptibility of bimetallic (S = 3/2, s = 1/2) chains composed of Cu ions linked to different 3d ions by fitting experimental data. We reach the remarkable consistency of the density functional theory estimates of the magnetic couplings in $Cr_8$ molecule and provide strong support to the spin models exploited in the literature.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 5-6; 992-998
    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:
    Magnetization Process and Adiabatic Demagnetization of the Antiferromagnetic Spin-1/2 Heisenberg Cubic Cluster
    Autorzy:
    Strečka, J.
    Čisárová, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1366469.pdf
    Data publikacji:
    2014-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.10.Jm
    75.30.Sg
    75.40.Cx
    75.50.Ee
    75.60.Ej
    Opis:
    A full energy spectrum of the spin-1/2 Heisenberg cubic cluster is used to investigate a low-temperature magnetization process and adiabatic demagnetization of this zero-dimensional 2×2×2 quantum spin system. It is shown that the antiferromagnetic spin-1/2 Heisenberg cube exhibits at low enough temperatures a stepwise magnetization curve with four intermediate plateaux at zero, one quarter, one half, and three quarters of the saturation magnetization. We have also found the enhanced magnetocaloric effect close to level-crossing fields that determine transitions between the intermediate plateaux.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 1; 26-27
    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
      Wyświetlanie 1-14 z 14

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies