Quasi-wetting and morphological phase transitions in confined far-from-equilibrium magnetic thin films

TL;DR

This paper investigates the complex phase transitions in confined, far-from-equilibrium magnetic thin films, revealing a rich phase diagram with multiple transitions influenced by finite-size effects and nonequilibrium dynamics.

Contribution

It introduces a detailed study of quasi-wetting and morphological transitions in nonequilibrium magnetic films, highlighting differences from equilibrium behavior and mapping a complex phase diagram.

Findings

Identification of a quasi-wetting transition between localized and delocalized interfaces.

Discovery of eight distinct phases in finite systems due to nonequilibrium effects.

Collapse of the ordered phase in the thermodynamic limit, leaving only two phases in the disordered regime.

Abstract

The growth of confined magnetic films with ferromagnetic interactions between nearest-neighbor spins is studied in a stripped $(1+1)-$dimensional rectangular geometry. Magnetic films are grown irreversibly by adding spins at the boundaries of the growing interface. A competing situation with two opposite short range surface magnetic fields of the same magnitude is analyzed. Due to the antisymmetric condition considered, an interface between domains with spins having opposite orientations develops along the growing direction. Such interface undergoes a localization-delocalization transition that is identified as a quasi-wetting transition, in qualitative agreement with observations performed under equilibrium conditions. In addition, the film also exhibits a growing interface that undergoes morphological transitions in the growth mode. It is shown that, as a consequence of the nonequilibrium nature of the investigated model, the subtle interplay between finite-size effects, wetting, and interface growth mechanisms leads to more rich and complex physical features than in the equilibrium counterpart. Indeed, a phase diagram that exhibits eight distinct regions is evaluated and discussed. In the thermodynamic limit, the whole ordered phase (which contains the quasi-wetting transition) collapses, while within the disordered phase, standard extrapolation procedures show that only two regions are present in the phase diagram of the infinite system.