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The effect of a surface on the dynamic and thermodynamic properties of S=1 Heisenberg ferromagnet with biquadratic exchange

Pavkov, M; Škrinjar, M; Kapor, D; Stojanović, S - In: Physica A: Statistical Mechanics and its Applications 280 (2000) 3, pp. 465-483

Properties of semi-infinite (S=1) Heisenberg ferromagnet with biquadratic exchange were studied in terms of surface exchange (ε=IS/I) and biquadratic coupling (a). It was shown that a strict correlation exists, depending on ε, between the type of surface spin waves (acoustic or optical) and...

Persistent link: https://www.econbiz.de/10011057055

Quantum Monte-Carlo study of the Heisenberg chain with long-range ferromagnetic interactions

Vassiliev, O.N; Rojdestvenski, I.V; Cottam, M.G - In: Physica A: Statistical Mechanics and its Applications 294 (2001) 1, pp. 139-154

Thermodynamic properties of the Heisenberg ferromagnetic chain are investigated using the Handscomb quantum Monte-Carlo method. The spin–spin interaction is long-range with the spin coupling parameter depending as r−p on the distance r between spins. Parameter p is in the range 1p⩽4. The...

Persistent link: https://www.econbiz.de/10011062847

Mean-field renormalization group for the q-state clock spin-glass model

Chen, Shyh-Tzer - In: Physica A: Statistical Mechanics and its Applications 229 (1996) 2, pp. 181-187

= 4 clock, the transition from paramagnet to spin glass is an anisotropic spin-glass phase. However, for q ⩾ 5 clock, the … result of anisotropic spin-glass phase depends on the temperature and the distribution of random coupling. While the …

Persistent link: https://www.econbiz.de/10011059561

A new anisotropic continuum model for traffic flow

Gupta, A.K.; Katiyar, V.K. - In: Physica A: Statistical Mechanics and its Applications 368 (2006) 2, pp. 551-559

headway in terms of the density. The new model contains an additional speed gradient term (Anisotropic term) in comparison to … the Berg's model [Berg et al., Phys. Rev. E 61(2) (2000) 1056]. This anisotropic term guarantees the property that the … (1995) 277]. In our general model, a traffic dependent anisotropic factor controls the non-isotropic character and diffusive …

Persistent link: https://www.econbiz.de/10011061570

Percolation exponents and threshold in two nearly ideal anisotropic continuum systems

Wu, Junjie; McLachlan, D.S. - In: Physica A: Statistical Mechanics and its Applications 241 (1997) 1, pp. 360-366

Compressed discs made from graphite and, its mechanical but not electrical isomorph, boron nitride, as well as graphite-boron nitride powders, undergoing compression, are nearly ideal continuum percolation systems; as the ratio of their conductivities is 10−18 and the scatter of the...

Persistent link: https://www.econbiz.de/10011062748

Time-convolutionless mode-coupling theory near the glass transition—A recursion formula and its asymptotic solutions

Tokuyama, Michio - In: Physica A: Statistical Mechanics and its Applications 430 (2015) C, pp. 156-170

The time-convolutionless mode-coupling theory (TMCT) equation for the intermediate scattering function fα(q,t) derived recently by the present author is analyzed mathematically and numerically, where α=c stands for a collective case and α=s for a self case. All the mathematical formulations...

Persistent link: https://www.econbiz.de/10011264568

Correlation identities and rigorous upper bounds on the critical temperature for the spin-1 Blume–Capel model on a Kagome lattice

Santos, Jander P.; Sá Barreto, F.C. - In: Physica A: Statistical Mechanics and its Applications 421 (2015) C, pp. 548-561

Spin correlation identities for the Blume–Capel model on Kagome lattice are derived and combined with rigorous correlation inequalities lead to upper bounds on the critical temperature. From the spin correlation identities the mean field approximation and the effective field approximation...

Persistent link: https://www.econbiz.de/10011193985

The ferromagnet spin-1/2 Ising superlattice in a transverse field

Dujardin, F.; Stébé, B.; Ainane, A.; Saber, M. - In: Physica A: Statistical Mechanics and its Applications 269 (1999) 2, pp. 322-328

The phase transitions of a ferromagnet spin-1/2 Ising superlattice consisting of two different materials are examined using the effective field theory. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell, exchange interactions in...

Persistent link: https://www.econbiz.de/10010873441

Magnetic properties of a mixed spin- 1/2 and spin- 3/2 transverse Ising model in a longitudinal magnetic field

Liang, Ya-Qiu; Wei, Guo-Zhu; Ma, Feng-Cai; Song, Guo-Li - In: Physica A: Statistical Mechanics and its Applications 387 (2008) 18, pp. 4513-4518

The mixed spin- 1/2 and spin- 3/2 transverse Ising model in a longitudinal magnetic field is studied within the framework of the effective-field theory with correlations. In this approach the effective-field equations are derived by using a probability distribution method based on the...

Persistent link: https://www.econbiz.de/10010873853

The site-diluted spin-12 Ising film

Saber, A.; Ainane, A.; Dujardin, F.; Saber, M.; Stébé, B. - In: Physica A: Statistical Mechanics and its Applications 269 (1999) 2, pp. 329-343

The phase transitions of a diluted spin-12 Ising film are examined using the framework of the effective field theory with a probability distribution technique that accounts for the single-site spin correlations. The critical temperature Tc/J of the system is calculated as a function of the...

Persistent link: https://www.econbiz.de/10011057074