Critical behavior of the liquid gas transition of 4 He confined in a silica aerogel
arXiv:1506.07750 · doi:10.1007/s10909-012-0740-2
Abstract
We have studied 4 He confined in a 95% porosity silica aerogel in the vicinity of the bulk liquid gas critical point. Both thermodynamic measurements and light scattering experiments were performed to probe the effect of a quenched disorder on the liquid gas transition, in relation with the Random Field Ising Model (RFIM). We find that the hysteresis between condensation and evaporation present at lower temperatures disappears at a temperature T ch between 25 and 30 mK below the critical point. Slow relaxations are observed for temperatures slightly below T ch , indicating that some energy barriers, but not all, can be overcome. Above T ch , no density step is observed along the (reversible) isotherms, showing that the critical behavior of the equilibrium phase transition in presence of disorder, if it exists, is shifted to smaller temperatures, where it cannot be observed due to the impossibility to reach equilibrium. Above T ch , light scattering exhibits a weak maximum close to the pressure where the isotherm slope is maximal. This behavior can be accounted for by a simple model incorporating the compression of 4 He close to the silica strands.
arXiv comment6 pages
References in corpus (11)
- Hysteresis and hierarchies: dynamics of disorder-driven first-order phase transformations
- Capillary condensation in disordered porous materials: hysteresis versus equilibrium behavior
- Critical Exponents of the Three Dimensional Random Field Ising Model
- Critical Exponents of the Three Dimensional Random Field Ising Model
- Local mean-field study of capillary condensation in silica aerogels
- Glassy transition in the three-dimensional random field Ising model
- Elusive Glassy Phase in the Random Field Ising Model
- Helium adsorption in silica aerogel near the liquid-vapor critical point
- Evidence for a disorder driven phase transition in the condensation of 4He in aerogels
- Probing helium interfaces with light scattering : from fluid mechanics to statistical physics
- A temperature-controlled device for volumetric measurements of Helium adsorption in porous media