Equilibrium phase transitions in a porous medium

Article

关键词: DILUTE ISING-MODEL;    RANDOM-FIELD TRANSITION;    SIZE-SCALING ANALYSIS;    CRITICAL-BEHAVIOR;    BINARY-LIQUID;    SPIN SYSTEMS;    MONTE-CARLO;    HE-3-HE-4 MIXTURE;    QUENCHED DISORDER;    FORM-FACTOR;   

DOI  :  10.1103/PhysRevB.53.148

来源: SCIE

【 摘 要 】

Static critical phenomena of a three-dimensional Ising model confined in a porous medium made by spinodal decomposition have been studied using large-scale Monte Carlo simulations. We thus examine the influence of the geometry of Vycor-like materials on phase transitions. No surface interactions (preference of the Vycor-like material for one phase above the other) are taken into account. We find that the critical temperature depends on the average pore size D as T-c(D)=T-c((infinity))-c/D. The critical exponents are independent of pore size: we find nu=0.8+/-0.1, gamma=1.41-0.1, beta=0.65+/-0.13. No divergence is observed for the specific heat, indicating alpha less than or equal to 0. All data for all pore sizes can be collapsed well with the scaling function for the magnetic susceptibility chi L(-gamma/nu) = <(chi)over tilde>(tL(1/nu)), where t=T/T-c(D)-1. These critical phenomena are consistent with those computed for the randomly site-diluted Ising model. Experimental realizations of our numerical experiments are discussed.

【 授权许可】

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