Accelerated inertial regime in the spinodal decomposition of magnetic fluids

Soft Matter. 2023 Mar 29;19(13):2370-2376. doi: 10.1039/d3sm00285c.

Abstract

Furukawa predicted that at late times, the domain growth in binary fluids scales as (t) ∼ t2/3, and the growth is driven by fluid inertia. The inertial growth regime has been highly elusive in molecular dynamics (MD) simulations. We perform coarsening studies of the (d = 3) Stockmayer (SM) model comprising of magnetic dipoles that interact via long-range dipolar interactions as well as the usual Lennard-Jones (LJ) potential. This fascinating polar fluid exhibits a gas-liquid phase coexistence, and magnetic order even in the absence of an external field. From comprehensive MD simulations, we observe the inertial scaling [(t) ∼ t2/3] in the SM fluid for an extended time window. Intriguingly, the fluid inertia is overwhelming from the outset - our simulations do not show the early diffusive regime [(t) ∼ t1/3] and the intermediate viscous regime [(t) ∼ t] prevalent in LJ fluids.