Articles de revues : « Diluted spin systems »

1

Bobák, A., et M. Jaščur. « Ferrimagnetism in diluted mixed Ising spin systems ». Physical Review B 51, n^o 17 (1 mai 1995) : 11533–37. http://dx.doi.org/10.1103/physrevb.51.11533.

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Xin, Z. H., G. Z. Wei, G. Z. Wei, T. S. Liu et T. S. Liu. « Thermodynamics of Diluted Mixed Spin Ising Systems ». physica status solidi (b) 209, n^o 1 (septembre 1998) : 145–51. http://dx.doi.org/10.1002/(sici)1521-3951(199809)209:1<145 ::aid-pssb145>3.0.co;2-s.

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Sobotta, G. « Exact treatment of finite diluted spin systems ». Physica A : Statistical Mechanics and its Applications 136, n^o 2-3 (juin 1986) : 475–86. http://dx.doi.org/10.1016/0378-4371(86)90262-1.

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Sobotta, G. « Exact treatment of finite diluted spin systems ». Physica A : Statistical Mechanics and its Applications 136, n^o 2-3 (juin 1986) : 487–94. http://dx.doi.org/10.1016/0378-4371(86)90263-3.

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Sobotta, G. « Exact treatment of finite diluted spin systems ». Physica A : Statistical Mechanics and its Applications 136, n^o 2-3 (juin 1986) : 495–524. http://dx.doi.org/10.1016/0378-4371(86)90264-5.

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Franz, Silvio, Michele Leone et Fabio Lucio Toninelli. « Replica bounds for diluted non-Poissonian spin systems ». Journal of Physics A : Mathematical and General 36, n^o 43 (15 octobre 2003) : 10967–85. http://dx.doi.org/10.1088/0305-4470/36/43/021.

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FRANZ, SILVIO, et FABIO LUCIO TONINELLI. « THE KAC LIMIT FOR DILUTED SPIN GLASSES ». International Journal of Modern Physics B 18, n^o 04n05 (20 février 2004) : 675–79. http://dx.doi.org/10.1142/s021797920402429x.

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We study diluted spin glass models in arbitrary dimension, where each spin interacts with a finite number of other spins chosen at random with a probability decaying to zero over some distance γ-1. For systems with pairwise interactions we show that the infinite-volume free energy converges to that of the mean-field Viana–Bray model,1 in the Kac limit γ→0. For p-spin like models we get only one bound: the free-energy is bounded from above by the one of the mean-field diluted p-spin.

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8

Mauksch, Michael, et Svetlana B. Tsogoeva. « Spin-paired solvated electron couples in alkali–ammonia systems ». Physical Chemistry Chemical Physics 20, n^o 44 (2018) : 27740–44. http://dx.doi.org/10.1039/c8cp05058a.

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Murtazaev, Akai K., A. B. Babaev et G. Ya Aznaurova. « Phase Transitions in 3D Site-Diluted Potts Model with Spin States q=4 ». Solid State Phenomena 168-169 (décembre 2010) : 357–60. http://dx.doi.org/10.4028/www.scientific.net/ssp.168-169.357.

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We study the phase transitions and critical phenomena in 3D site-diluted (with nonmagnetic impurities) Potts model with spin states q=4 by Monte-Carlo method. The systems with linear sizes L=20-32 and spin concentrations p=1.00, 0.90, 0.65 are examined. Using the Binder cumulants method the forth order it is shown that the second-order phase transition is observed in strongly diluted model at spin concentration p=0.65; the pure model (p=1.00) and weakly diluted one (p=0.90) reveals the first-order phase transition. On the basis of finite-size scaling theory the static critical parameters of heat capacity, susceptibility, magnetization, and correlation length exponent are calculated.

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Lelarge, Marc, et Mendes Oulamara. « Replica Bounds by Combinatorial Interpolation for Diluted Spin Systems ». Journal of Statistical Physics 173, n^o 3-4 (3 février 2018) : 917–40. http://dx.doi.org/10.1007/s10955-018-1964-6.

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Babaev, Albert Babaevich, et Akai Kurbanovich Murtazaev. « DISTRIBUTION OF THERMODYNAMIC PARAMETERS IN THE DISCRETE DISORDERED POTT’S MODEL. RESULTS OF COMPUTER SIMULATION ». Herald of Omsk University 25, n^o 1 (21 mai 2020) : 7–12. http://dx.doi.org/10.24147/1812-3996.2020.25(1).7-12.

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Using the Monte Carlo method, we study the distribution of thermodynamic parameters in a strongly disordered Potts model with the number of spin states q = 4. For this model, relative dispersions of magnetization Rm and susceptibility R are calculated. It is shown that in this model, the relative dispersions of Rm and R lead to nonzero values, which in-dicates poor self-averaging for magnetization and susceptibility in a strongly diluted mod-el. Averaging the thermodynamic parameters in a strongly diluted regime over an ensem-ble of disordered spin systems with different disorder implementations requires a signifi-cant increase in the number of disordered impurity configurations. Computer simulation was performed for spin systems with periodic boundary conditions at a spin concentration of p = 0.65. Systems with linear dimensions L  L  L= N, L = 60 were investigated.

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12

Walton, D. « Relaxation and aging in lattice glasses ». Canadian Journal of Physics 73, n^o 11-12 (1 novembre 1995) : 805–9. http://dx.doi.org/10.1139/p95-117.

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A sequential relaxation model for the susceptibility of site-diluted Ising systems is described. It is shown that the model, which yields an excellent fit to experimental results for the real part of the ac susceptibility of the site-diluted two-dimensional Ising spin glass, Fe0.4Mg0.6Cl2, predicts a change in susceptibility with time during aging that is confirmed by experiments on other spin glasses and the orientational glass KBr0.5CN0.5.

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13

GNANASEKAR, K., et K. NAVANEETHAKRISHNAN. « SPIN POLARON IN A QUANTUM DOT OF THE DILUTED MAGNETIC SEMICONDUCTORS ». Modern Physics Letters B 18, n^o 10 (20 avril 2004) : 419–26. http://dx.doi.org/10.1142/s0217984904006962.

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Theoretical investigations of spin polaron in a quantum dot in the "spin doping" superlattice systems Cd 1 - X in Mn X in Te/Cd 1 - X out Mn X out Te are presented. We estimated the donor ionization energy by variational technique and the spin polaronic shift using the mean field theory with modified Brillouin function. Our results show that significant enhancement of donor ionization energy and spin polaronic shift occur in a dot when compared to a quantum well, wire and bulk systems.

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Prudnikov, Vladimir V., Pavel V. Prudnikov, Evgenii A. Pospelov et Petr N. Malyarenko. « Peculiarities of Non-Equilibrium Critical Behavior for 3D Diluted Ising Model with Evolution from Low-Temperature Initial State ». Materials Science Forum 845 (mars 2016) : 85–88. http://dx.doi.org/10.4028/www.scientific.net/msf.845.85.

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The Monte Carlo description of aging properties in nonequilibrium critical behaviour of 3D site-diluted Ising model is considered with evolution from ordered initial state with wide range of spin concentrations. At first, it was shown, that pinning of domain walls on defects leeds to a sharp change of aging properties in diluted systems in comparison with pure system. Therefore, the asymptotic value of the fluctuation-dissipative relation becomes equal to null for diluted systems, while for pure system = 0.784(5).

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15

Bobák, A., et M. Jurcisin. « Ferrimagnetism in Diluted Mixed Spin-1/2 and Spin-3/2 Ising Systems ». Le Journal de Physique IV 07, n^o C1 (mars 1997) : C1–179—C1–180. http://dx.doi.org/10.1051/jp4:1997165.

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Jonker, B. T., X. Liu, W. C. Chou, A. Petrou, J. Warnock, J. J. Krebs et G. A. Prinz. « Spin separation in diluted magnetic semiconductor quantum well systems (invited) ». Journal of Applied Physics 69, n^o 8 (15 avril 1991) : 6097–102. http://dx.doi.org/10.1063/1.347779.

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Kalashnikov, Ivan A., et Pavel V. Prudnikov. « Field-Theory Description of Nonequilibrium Critical Dynamics for Spin Systems ». Solid State Phenomena 190 (juin 2012) : 23–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.23.

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Renormalization-group approach is applied to investigate the short-time nonequilibriumcritical behavior of pure and diluted spin systems with nonmagnetic point-like impurities.The dissipative relaxation dynamics with non-conserved order parameter is considered. For thefirst time the description of the order parameter growth induced by the initial nonequilibriumstate of system is carried out at fixed dimension d = 3 without use of ε-expansion.

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Cieplak, Marta Z., Tomasz R. Gawron et Marek Cieplak. « Dynamics of diluted antiferromagnetic Ising spin systems on the fcc lattice ». Physical Review B 39, n^o 10 (1 avril 1989) : 6757–64. http://dx.doi.org/10.1103/physrevb.39.6757.

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Tang, Guixin, et Wolfgang Nolting. « Effects of dilution and disorder on magnetism in diluted spin systems ». physica status solidi (b) 244, n^o 2 (février 2007) : 735–47. http://dx.doi.org/10.1002/pssb.200642322.

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Murtazaev, A. K., et A. B. Babaev. « Investigation of Phase Transitions in the Site-Diluted Three-Dimensional Potts Model ». Solid State Phenomena 190 (juin 2012) : 687–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.687.

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The phase transitions and critical phenomena in three-dimensional (3D) site-diluted 3-and 4-state Potts models is investigated by Monte-Carlo method based on the highly efficient Wolff algorithm. The systems with linear sizesL=20-44 at spin concentrationsp=1.00, 0.95, 0.90, 0.80, 0.70, 0.65 are explored. The second-order phase transition is shown to occur in the three-dimensional 3-state Potts model with nonmagnetic impurities. In the 4-state Potts model there are observed first-order phase transitions in weakly diluted state, when the model is strongly diluted the first-order phase transitions change to the second-order one. On the basis of the finite-size scaling theory static critical exponents of specific heatα, susceptibilityγ, magnetizationβ, and exponent of correlation radiusνfor the systems under study are calculated.

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Бабаев, А. Б., А. К. Муртазаев, Г. Я. Атаева, Т. Р. Ризванова et М. Р. Джамалудинов. « Компьютерное моделирование критического поведения двумерной слаборазбавленной антиферромагнитной модели Поттса на треугольной решетке ». Физика твердого тела 60, n^o 6 (2018) : 1169. http://dx.doi.org/10.21883/ftt.2018.06.45995.07m.

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AbstractThe critical behavior of a two-dimensional weakly diluted antiferromagnetic Potts model with spin states q = 3 on a triangular lattice is computationally simulated. The systems with periodic boundary conditions were calculated, when spin concentrations p were 1.0 and 0.9. Systems with linear dimensions L × L = N and L = 9–144 were considered. Static critical exponents of heat capacity α, the susceptibility γ, the order parameter β, and critical exponent ν for a correlation radius are calculated based on a theory of finite-dimensional scaling.

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22

SOUMA, SATOFUMI, SEUNG JOO LEE et TAE WON KANG. « NUMERICAL STUDY OF FERROMAGNETISM IN DILUTED MAGNETIC SEMICONDUCTOR QUANTUM-WELLS ». International Journal of Modern Physics B 19, n^o 19 (30 juillet 2005) : 3151–60. http://dx.doi.org/10.1142/s0217979205031973.

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We study the ferromagnetism in III-V diluted magnetic semiconductor (DMS) quantum-wells theoretically and numerically taking into account the occupation of multiple subbands by holes in quantum wells. Starting from the mean-field theory of carrier-induced ferromagnetism in III-V DMS along with the exchange-correlation interaction of holes within the local spin density approximation, we found that the ferromagnetic transition temperature Tc of DMS quantum-wells exhibits step-function-like dependence on the hole density, reflecting the quasi-two-dimensional nature of systems. Moreover, the temperature dependence of the spin polarization shows quite distinct characteristics depending on the hole density.

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Aoyama, Yoshio, et Motoyuki Tanaka. « On Phase Transitions of Diluted Ising Spin Systems with Spatially Anisotropic Interactions ». Journal of the Physical Society of Japan 65, n^o 12 (15 décembre 1996) : 4094–95. http://dx.doi.org/10.1143/jpsj.65.4094.

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Xin, Z. H., G. Z. Wei et T. S. Liu. « Magnetic properties of ground state in diluted mixed-spin Ising ferrimagnetic systems ». Journal of Magnetism and Magnetic Materials 176, n^o 2-3 (décembre 1997) : 206–12. http://dx.doi.org/10.1016/s0304-8853(97)00544-1.

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Isoda, Makoto, et Shigeyoshi Mori. « Order by disorder in diluted two-dimensional extended antiferromagnetic Ising spin systems ». Journal of Magnetism and Magnetic Materials 310, n^o 2 (mars 2007) : e429-e431. http://dx.doi.org/10.1016/j.jmmm.2006.10.439.

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Chakraborty, Akash, et Georges Bouzerar. « Long wavelength spin dynamics in diluted magnetic systems : Scaling of magnon lifetime ». Journal of Magnetism and Magnetic Materials 381 (mai 2015) : 50–55. http://dx.doi.org/10.1016/j.jmmm.2014.12.064.

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Bhagat, S. M., et H. A. Sayadian. « Magnetic resonance in random spin systems : Diluted magnetic semiconductors, universal temperature dependence ». Journal of Magnetism and Magnetic Materials 61, n^o 1-2 (septembre 1986) : 151–61. http://dx.doi.org/10.1016/0304-8853(86)90077-6.

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Affes, Karim, Yogendra Singh et Kamel Boukheddaden. « Electro-Elastic Modeling of Thermal Spin Transition in Diluted Spin-Crossover Single Crystals ». International Journal of Molecular Sciences 23, n^o 22 (10 novembre 2022) : 13854. http://dx.doi.org/10.3390/ijms232213854.

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Spin-crossover solids have been studied for many years for their promising applications as optical switches and reversible high-density memories for information storage. This study reports the effect of random metal dilution on the thermal and structural properties of a spin-crossover single crystal. The analysis is performed on a 2D rectangular lattice using an electro-elastic model. The lattice is made of sites that can switch thermally between the low-spin and high-spin states, accompanied by local volume changes. The model is solved by Monte Carlo simulations, running on the spin states and atomic positions of this compressible 2D lattice. A detailed analysis of metal dilution on the magneto-structural properties allows us to address the following issues: (i) at low dilution rates, the transition is of the first order; (ii) increasing the concentration of dopant results in a decrease in cooperativity and leads to gradual transformations above a threshold concentration, while incomplete spin transitions are obtained for big dopant sizes. The effects of the metal dilution on the spatiotemporal aspects of the spin transition along the thermal transition and on the low-temperature relaxation of the photo-induced metastable high-spin states are also studied. Significant changes in the organization of the spin states are observed for the thermal transition, where the single-domain nucleation caused by the long-range elastic interactions is replaced by a multi-droplet nucleation. As to the issue of the relaxation curves: their shape transforms from a sigmoidal shape, characteristic of strong cooperative systems, into stretched exponentials for high dilution rates, which is the signature of a disordered system.

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Turek, Ilja, K. Carva et J. Kudrnovsky. « Transport Properties of (Ga,Mn)As Diluted Magnetic Semiconductors in the Bulk and in Layered Systems ». Advances in Science and Technology 52 (octobre 2006) : 1–10. http://dx.doi.org/10.4028/www.scientific.net/ast.52.1.

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Transport properties of systems based on diluted magnetic semiconductors (Ga,Mn)As are investigated theoretically by means of the Kubo linear response theory. The underlying electronic structure is obtained within the local spin-density approximation using the scalarrelativistic tight-binding linear muffin-tin orbital (TB-LMTO) method. The effect of substitutional randomness on the electronic structure and on the transport properties is systematically described in the coherent potential approximation (CPA). The quantities studied include the residual resistivities of the bulk alloys as well as conductances of epitaxial trilayers Cr/(Ga,Mn)As/Cr (001) in the current-perpendicular-to-plane (CPP) orientation. The results witness that various compensating defects such as As antisite atoms and Mn interstitials have much stronger detrimental effect on the spin polarization of the CPP conductances as compared to their influence on the spin polarization of the bulk conductivities.

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Murtazaev, A. K., et A. B. Babaev. « Computer Simulation of the Phase Transitions in Three-Dimensional Weakly Diluted Spin Systems ». Journal of Surface Investigation : X-ray, Synchrotron and Neutron Techniques 16, n^o 2 (avril 2022) : 221–25. http://dx.doi.org/10.1134/s1027451022030156.

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Pérez-Merchancano, S. T., H. Paredes Gutiérrez et G. E. Marques. « Spin transport properties in double-barrier systems with diluted magnetic semiconductor doped layers ». Microelectronics Journal 39, n^o 11 (novembre 2008) : 1339–40. http://dx.doi.org/10.1016/j.mejo.2008.01.081.

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Henner, E. K., et V. K. Henner. « About the velocity of establishment of quasi-equilibrium in magnetically diluted spin-systems ». Physics Letters A 127, n^o 6-7 (mars 1988) : 322–24. http://dx.doi.org/10.1016/0375-9601(88)90577-4.

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EBERT, H., H. AKAI, H. MARUYAMA, A. KOIZUMI, H. YAMAZAKI et G. SCHÜTZ. « THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE MAGNETIC X-RAY DICHROISM IN DILUTED AND CONCENTRATED TRANSITION METAL ALLOYS ». International Journal of Modern Physics B 07, n^o 01n03 (janvier 1993) : 750–55. http://dx.doi.org/10.1142/s021797929300158x.

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By combining the Coherent Potential Approximation with the spin polarized relativistic Korringa-Kohn-Rostoker method of band structure calculation it got possible to describe the electronic structure of disordered magnetic alloys in a fully relativistic way. This new development allowed us to extend our theoretical description of the magnetic X-ray dichroism (MXD), which is based on the spin polarized relativistic Green's function formalism, to deal not only with pure and impurity systems but also with this interesting class of materials. We demonstrate this by calculations of K- and L-edge MXD spectra in the alloy systems FexCo1−x, CoxPt1−x and FexPt1−x, which are found in a very satisfying agreement with corresponding experimental data. In addition the relationship of the integrated MXD-spectra with the calculated spin magnetic moments is discussed in short.

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Jin, C. Q. « Using Pressure Effects to Create New Emergent Materials by Design ». MRS Advances 2, n^o 48 (2017) : 2587–96. http://dx.doi.org/10.1557/adv.2017.495.

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ABSTRACTNew emergent materials of novel electromagnetic properties are discussed, based primarily on our recent works. The use of pressure effects in terms of self oxidization, inner compression and pure doping in discovering new emergent materials is highlighted. Materials addressed include (I) new correlated oxides such as high-Tc cuprate superconductors; (II) new intermetallic materials such as diluted magnetic semiconductors with independent spin & charge doping; the “111” type iron based superconducting systems; (III) compounds with strong spin orbit coupling, such as itinerant ferromagnetic ruthenates etc.

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TODO, S., K. KATO, H. TAKAYAMA, K. HARADA, N. KAWASHIMA et S. MIYASHITA. « QUANTUM MONTE CARLO STUDY OF SITE-DILUTED HEISENBERG ANTIFERROMAGNET ON A SQUARE LATTICE ». International Journal of Modern Physics C 10, n^o 08 (décembre 1999) : 1399–407. http://dx.doi.org/10.1142/s0129183199001170.

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Ground-state phase transition of site-diluted Heisenberg antiferromagnets on a square lattice is studied. By using the continuous-time loop algorithm, we perform large-scale quantum Monte Carlo simulation on large systems at quite low temperatures. It is found that the critical concentration of magnetic sites is independent of the spin size S, and equal to the classical percolation threshold. However, the existence of quantum fluctuations makes the critical exponents deviate from those of the classical percolation transition. It is found that the transition is not universal, i.e., the critical exponents depend on the spin size S.

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Assefa, Gezahegn. « Electric Field Controlled Itinerant Carrier Spin Polarization in Ferromagnetic Semiconductors ». Advances in Condensed Matter Physics 2021 (12 juillet 2021) : 1–5. http://dx.doi.org/10.1155/2021/6663876.

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Electric field control of magnetic properties has been achieved across a number of different material systems. In diluted magnetic semiconductors (DMSs), ferromagnetic metals, multiferroics, etc., electrical manipulation of magnetism has been observed. Here, we study the effect of an electric field on the carrier spin polarization in DMSs ( GaAsMn ); in particular, emphasis is given to spin-dependent transport phenomena. In our system, the interaction between the carriers and the localized spins in the presence of electric field is taken as the main interaction. Our results show that the electric field plays a major role on the spin polarization of carriers in the system. This is important for spintronics application.

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HOANG, ANH-TUAN. « CURIE TEMPERATURE OF THE TWO-BAND MODEL FOR DILUTED MAGNETIC SEMICONDUCTORS IN COHERENT POTENTIAL APPROXIMATION ». Modern Physics Letters B 23, n^o 26 (20 octobre 2009) : 3171–77. http://dx.doi.org/10.1142/s021798490902120x.

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Coherent potential approximation (CPA) is extended to a two-band model for diluted magnetic semiconductors (DMS). The magnetic transition temperature Tc as a function of magnetic coupling constants, hopping parameters and carrier densities is calculated by minimizing the free energy of the coupled carrier-localized spin system. It is shown that Tc can be substantially raised by considering multiband systems.

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Coey, J. M. D. « Noncollinear spin structures ». Canadian Journal of Physics 65, n^o 10 (1 octobre 1987) : 1210–32. http://dx.doi.org/10.1139/p87-197.

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A survey of experimental results on noncollinear spin structures in crystalline and amorphous ionic materials is given. The occurrence of coherent helical, triangular, and canted structures in pure crystals is related to the presence of competing interactions: topologically frustrated antiferromagnetic superexchange, positive and negative exchange coupling with different shells of neighbours, symmetric and antisymmetric exchange, or exchange and single-ion anisotropy. These ideas are extended to crystal surfaces, disordered crystals, mixed crystals, amorphous compounds, and complex multicomponent glasses. Random noncollinear structures found in all these materials are due to randomly competing interactions. A distinction is made between isotropic random structures, where spin correlations are very short-ranged in all directions, and those structures where comparatively long-range longitudinal ferro-, antiferro-, or ferrimagnetic correlations coexist with transverse spin freezing having correlations only on the scale of nearest neighbour distances. A generalized magnetic phase diagram for diluted random magnets is presented. It is emphasized that important aspects of those systems now known as "reentrant spin glasses" had already been described in diamagnetically substituted ferrites many years previously.

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Szałowski, Karol, et Tadeusz Balcerzak. « Critical Temperature of Site-Diluted Spin-1/2 Systems with Long-Range Ferromagnetic Interactions ». Journal of the Physical Society of Japan 83, n^o 4 (15 avril 2014) : 044002. http://dx.doi.org/10.7566/jpsj.83.044002.

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Бабаев, А. Б., et А. К. Муртазаев. « Фазовые переходы в низкоразмерных неупорядоченных моделях Поттса ». Физика твердого тела 62, n^o 5 (2020) : 757. http://dx.doi.org/10.21883/ftt.2020.05.49241.17m.

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Abstract The Monte Carlo method is used to study phase transitions in disordered two-dimensional Potts models in which disorder is realized as nonmagnetic impurities. The temperature dependences of the thermodynamic parameters have been calculated for specific heat C , susceptibility χ, and fourth-order Binder cumulants in the dependence on spin concentration p . The calculations have been performed for the system with periodic boundary conditions. The systems with linear sizes L × L = N , L = 20–160 are considered. The incorporation of nonmagnetic impurities to a spin system is shown to possibly lead to a change of the first-order phase transition to a second-order phase transition. The problem of the universality classes of the critical behavior of low-dimensional diluted systems is discussed.

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Муртазаев, А. К., et А. Б. Бабаев. « Фазовые переходы в трехмерной слабо разбавленной модели Поттса с q=5 ». Физика твердого тела 63, n^o 10 (2021) : 1644. http://dx.doi.org/10.21883/ftt.2021.10.51417.047.

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The study of phase transitions in a three-dimensional weakly diluted 5-state Potts model is carried out by computer modeling. Systems with linear sizes L × L × L = N, L = 10 ÷ 40 at a spin concentration p = 1.00, 0.90 are considered. The obtained numerical data indicate that the introduction of an insignificant disorder in the form of non-magnetic impurities (p = 0.90) in the three-dimensional 5 - state Potts model is not essential for a phase transition of the first order.

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Муртазаев, А. К., А. Б. Бабаев et Г. Я. Атаева. « Фазовые переходы в двумерной слабо разбавленной пятивершинной модели Поттса ». Физика твердого тела 62, n^o 7 (2020) : 1088. http://dx.doi.org/10.21883/ftt.2020.07.49478.051.

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Computer simulation was used to study phase transitions in the two-dimensional weakly diluted Potts model on a square lattice at q=5. Systems with linear dimensions L×L=N, L=10-120 are considered. Based on fourth-order Binder cumulants, it was shown that the introduction of nonmagnetic impurities into the spin system described by the two-dimensional Potts model with q=5 leads to a change in the first-order phase transition to the second-order phase transition.

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Vakilov, Andrey N. « Zeros of Partition Function and Critical Exponents of the 3D Diluted Ising Model ». Materials Science Forum 845 (mars 2016) : 150–53. http://dx.doi.org/10.4028/www.scientific.net/msf.845.150.

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We used a Monte Carlo simulation of the structurally disordered three dimensional Ising model. For the systems with spin concentrations p = 0.95 ,0.8, 0.6 and 0.5 we calculated the correlation-length critical exponent ν by finite-size scaling. Extrapolations to the thermodynamic limit yield ν(0.95) = 0.705(5) ,ν(0.8) = 0.711(6),ν(0.6) = 0.736(6) and ν(0.5) = 0.744(6). These results are compatible with some previous estimates from a variety of sources. The analysis of the results demonstrates the nonuniversality of the critical behavior in the disordered Ising model.

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Bouzerar, G. « Magnetic spin excitations in diluted ferromagnetic systems : The case of Ga 1−x Mn x As ». Europhysics Letters (EPL) 79, n^o 5 (3 août 2007) : 57007. http://dx.doi.org/10.1209/0295-5075/79/57007.

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Eggenkamp, P. J. T., H. J. M. Swagten, T. Story, V. I. Litvinov, C. H. W. Swüste et W. J. M. de Jonge. « Calculations of the ferromagnet-to-spin-glass transition in diluted magnetic systems with an RKKY interaction ». Physical Review B 51, n^o 21 (1 juin 1995) : 15250–59. http://dx.doi.org/10.1103/physrevb.51.15250.

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de Albuquerque, Douglas F. « Study of universality class for site-bond correlated diluted spin systems in the n-vector model ». Journal of Magnetism and Magnetic Materials 219, n^o 3 (septembre 2000) : 349–54. http://dx.doi.org/10.1016/s0304-8853(00)00423-6.

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Lahiouel, R., R. M. Galera, A. P. Murani, J. Pierre et E. Siaud. « Ground state properties, anisotropy and spin relaxation in diluted Kondo systems Y1-x Ce x Zn ». Zeitschrift f�r Physik B Condensed Matter 62, n^o 4 (décembre 1986) : 457–62. http://dx.doi.org/10.1007/bf01303577.

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Budrin, K. S., Yu D. Panov, A. S. Moskvin et A. A. Chikov. « Unconventional phase separation in the model 2D spin-pseudospin system ». EPJ Web of Conferences 185 (2018) : 11006. http://dx.doi.org/10.1051/epjconf/201818511006.

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The competition of charge and spin orderings is a challenging problem for strongly correlated systems, in particular, for high-Tc cuprates. We addressed a simplified static 2D spin-pseudospin model which takes into account both conventional spin exchange coupling and the on-site and inter-site charge correlations. Classical Monte-Carlo calculations for large square lattices show that homogeneous ground state antiferromagnetic solutions found in a mean-field approximation are unstable with respect to phase separation into the charge and spin subsystems behaving like immiscible quantum liquids. In this case, with lowering of a temperature one can observe two sequential phase transitions: first, antiferromagnetic ordering in the spin subsystem diluted by randomly distributed charges, then, the charge condensation in the charge droplets. The inhomogeneous droplet phase reduces the energy of the system and changes the diagram of the ground states. On the other hand, the ground state energy of charge-ordered state in a mean-field approximation exactly matches the numerical Monte-Carlo calculations. The doped charges in this case are distributed randomly over a system in the whole temperature range. Various thermodynamic properties of the 2D spin-pseudospin system are studied by Monte-Carlo simulation.

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Мустафаева, С. Н., М. М. Асадов, С. С. Гусейнова, Н. З. Гасанов et В. Ф. Лукичев. « Ab initio расчеты электронных свойств, частотная дисперсия диэлектрических коэффициентов и край оптического поглощения монокристаллов TlInS-=SUB=-2-=/SUB=-<Sn&gt ; ». Физика твердого тела 64, n^o 6 (2022) : 628. http://dx.doi.org/10.21883/ftt.2022.06.52388.299.

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The method of computer simulation was used to study phase transitions in a two-dimensional site-diluted 3-state Potts model. Systems with linear dimensions L×L=N, L=10÷160 at spin concentrations p=1.00, 0.80 are considered. The obtained numerical data indicate that in the pure 3-state Potts model on a square lattice, a second-order phase transition is observed in accordance with the theory. The introduction of disorder in the form of non-magnetic impurities (p=0.80) in the Potts model with q=3 preserves the second-order phase transition.

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Murtazaev A. K., Babaev A. B., Ataeva G. Ya. et Babaev M. A. « Phase transitions in the diluted 2D three-state Potts model on a square lattice ». Physics of the Solid State 64, n^o 6 (2022) : 628. http://dx.doi.org/10.21883/pss.2022.06.53824.285.

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The computer simulation method was used to study phase transitions in a two-dimensional site-diluted 3-state Potts model. Systems with linear dimensions Lx L=N, L=10/160 at a spin concentration p=1.00, 0.80 are considered. The numerical data obtained indicate that in a pure 3-state Potts model on a square lattice, a phase transition of the second order is observed in accordance with the theory. The introduction of disorder in the form of non-magnetic impurities (p=0.80) in the 3-state Potts model preserves the phase transition of the second order. Keywords: Potts model, Monte Carlo method, thermodynamic parameters, disorder.

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