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 (Formula presented)(D)=(Formula presented)(∞)-c/D. The critical exponents are independent of pore size: we find ν=0.8±0.1, γ=1.4±0.1, β=0.65±0.13. No divergence is observed for the specific heat, indicating α≤0. All data for all pore sizes can be collapsed well with the scaling function for the magnetic susceptibility χ(Formula presented)=χ̃((Formula presented)), where t=T/(Formula presented)(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.
|Original language||English (US)|
|Number of pages||11|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1996|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics