Metamagnets in uniform and random fields

TL;DR

This paper investigates the phase behavior of a two-sublattice Ising metamagnet under uniform and random fields, revealing how the distribution of random fields influences the phase diagrams, especially with Gaussian randomness resembling dilute systems.

Contribution

It introduces a mean-field analysis of a metamagnet model considering both uniform and Gaussian-distributed random fields, highlighting the impact of randomness on phase diagram features.

Findings

Phase diagrams depend significantly on the random field distribution.

Gaussian random fields produce behavior similar to dilute Ising systems.

Qualitative features vary notably between uniform and random field cases.

Abstract

We study a two-sublattice Ising metamagnet with nearest and next-nearest-neighbor interactions, in both uniform and random fields. Using a mean-field approximation, we show that the qualitative features of the phase diagrams are significantly dependent on the distribution of the random fields. In particular, for a Gaussian distribution of random fields, the behavior of the model is qualitatively similar to a dilute Ising metamagnet in a uniform field.