The influence of long-range correlated defects on critical ultrasound propagation in solids

The effect of long-range correlated quenched structural defects on the critical ultrasound attenuation and sound velocity dispersion is studied for three-dimensional Ising-like systems. A field-theoretical description of the dynamic critical effects of ultrasound propagation in solids is performed with allowance for both fluctuation and relaxation attenuation mechanisms. The temperature and frequency dependences of the dynamical scaling functions of the ultrasound critical characteristics are calculated in a two-loop approximation for different values of the correlation parameter $a$ of the Weinrib-Halperin model with long-range correlated defects. The asymptotic behavior of the dynamical scaling functions in hydrodynamic and critical regions is separated. The influence of long-range correlated disorder on the asymptotic behavior of the critical ultrasonic anomalies is discussed.Comment: 12 RevTeX pages, 3 figure

Non-equilibrium critical behavior of thin Ising films

In this paper we study the non-equilibrium properties of Ising ferromagnetic films using Monte Carlo simulations by short-time dynamic method. We have found thickness dependency of critical exponents z, theta and b/n. Ageing effects were observed in non-equilibrium critical behavior. Former was carried out both from high-temperature and low-temperature initial states. A characteristic time of relaxation, which diverges at a transition temperature in the thermodynamic limit, is obtained as a function of the system size and waiting time

Non-equilibrium critical behavior of Heisenberg thin films

In this work we study the non-equilibrium properties of Heisenberg ferromagnetic films using Monte Carlo simulations by short-time dynamic method. By exploring the short-time scaling dynamics, we have found thickness dependency of critical exponents z, θ′ and β/v for ferromagnetic thin film. For calculating the critical exponents of ferromagnetic films we considered systems with linear size L = 128 and layers number N = 2; 4; 6; 10. Starting from initial configurations, the system was updated with Metropolis algorithm at the critical temperature

Non-equilibrium critical behavior of Heisenberg thin films

In this work we study the non-equilibrium properties of Heisenberg ferromagnetic films using Monte Carlo simulations by short-time dynamic method. By exploring the short-time scaling dynamics, we have found thickness dependency of critical exponents z, θ′ and β/v for ferromagnetic thin film. For calculating the critical exponents of ferromagnetic films we considered systems with linear size L = 128 and layers number N = 2; 4; 6; 10. Starting from initial configurations, the system was updated with Metropolis algorithm at the critical temperature

Non-equilibrium critical behavior of thin Ising films

In this paper we study the non-equilibrium properties of Ising ferromagnetic films using Monte Carlo simulations by short-time dynamic method. We have found thickness dependency of critical exponents z, theta and b/n. Ageing effects were observed in non-equilibrium critical behavior. Former was carried out both from high-temperature and low-temperature initial states. A characteristic time of relaxation, which diverges at a transition temperature in the thermodynamic limit, is obtained as a function of the system size and waiting time

Исследование неравновесной релаксации модели Гейзенберга с дальнодействующей корреляцией дефектов

Monte Carlo simulations of the short-time dynamic behavior are reported for three-dimensional Heisen- berg model with long-range correlated disorder at criticality, in the case corresponding to linear defects. Former was carried out both from high-temperature and low-temperature initial states. The static and dynamic critical exponents are determined for systems starting from different initial state. The obtained values of the exponents demonstrated a strong influence of long-range correlated quenched defects on the critical behavior of the systems described by the many-component order parameter.Было проведено компьютерное моделирование методами Монте-Карло для трехмерной модели Гейзенберга с дальнодействующей корреляцией дефектов вблизи критической точки в случае, соответствующем линейным дефектам. Моделирование проводилось как из высокотемпературного так и из низкотемпературного начального состояния. Статические и динамические критические индексы были рассчитаны для систем из различных начальных состояний. Полученные значения показателей демонстрируют сильное влияние дальнодействующей корреляции вмороженных дефектов структуры на критическое поведение систем с многокомпонентным параметром порядк