The effect of an external magnetic field on the gas-liquid transition in the Heisenberg spin fluid

TL;DR

This paper investigates how an external magnetic field influences the gas-liquid phase transition in a classical Heisenberg fluid, revealing a nonmonotonic effect on the critical temperature through theoretical phase diagrams.

Contribution

It provides a theoretical analysis of the phase behavior of Heisenberg fluids under magnetic fields using integral equations, highlighting nonmonotonic effects on critical points.

Findings

External magnetic fields cause nonmonotonic changes in the critical temperature.

The nonmonotonic behavior disappears with short-range spin interactions in the mean spherical approximation.

The phase diagrams are constructed considering correlations via integral equations.

Abstract

We present the theoretical phase diagrams of the classical Heisenberg fluid in an external magnetic field. A consistent account of correlations is carried out by the integral equation method. A nonmonotoneous effect of fields on the temperature of the gas-liquid critical point is found. Within the mean spherical approximation this nonmonotoneous behavior disappears for short-range enough spin-spin interactions.