Inverse freezing in the Ghatak-Sherrington model with a random field

TL;DR

This paper investigates how a random magnetic field influences inverse freezing phenomena in the Ghatak-Sherrington spin glass model, revealing that increasing the field suppresses the first-order transition associated with inverse freezing.

Contribution

It introduces the effect of a random magnetic field into the Ghatak-Sherrington model to study inverse freezing under non-frustrating disorder conditions.

Findings

Random magnetic field suppresses the inverse freezing transition.

First-order transition diminishes with increasing field strength.

Inverse freezing is sensitive to disorder type and field effects.

Abstract

The present work studies the Ghatak-Sherrington (GS) model in the presence of a magnetic random field (RF). Previous results obtained from GS model without RF suggest that disorder and frustration are the key ingredients to produce spontaneous inverse freezing (IF). However, in this model, the effects of disorder and frustration always appear combined. In that sense, the introduction of RF allows us to study the IF under the effects of a disorder which is not a source of frustration. The problem is solved within the one step replica symmetry approximation. The results show that the first order transition between the spin glass and the paramagnetic phases, which is related to the IF for a certain range of crystal field $D$, is gradually suppressed when the RF is increased.