Weak first order transition in the three-dimensional site-diluted Ising antiferromagnet in a magnetic field

TL;DR

This study uses numerical simulations to investigate the phase transition nature in a 3D site-diluted Ising antiferromagnet under a magnetic field, revealing a crossover from second-order to weak first-order transition at larger system sizes.

Contribution

It demonstrates that the phase transition exhibits a crossover from second-order to weak first-order behavior in large systems, providing new insights into disordered magnetic systems.

Findings

Signals of latent heat appear at large system sizes.

Critical behavior shows a crossover from second-order to first-order.

Proposes 'apparent' critical exponents for disordered first-order transitions.

Abstract

We perform intensive numerical simulations of the three-dimensional site-diluted Ising antiferromagnet in a magnetic field at high values of the external applied field. Even if data for small lattice sizes are compatible with second-order criticality, the critical behavior of the system shows a crossover from second-order to first-order behavior for large system sizes, where signals of latent heat appear. We propose "apparent" critical exponents for the dependence of some observables with the lattice size for a generic (disordered) first-order phase transition.