Magnetism of two-dimensional magnets in the presence of random fields

TL;DR

This paper develops an analytical model for 2D magnets showing how random magnetic fields induce a first-order phase transition and affect magnetic ordering at finite temperatures.

Contribution

It introduces an analytical equation for equilibrium magnetization considering random fields, revealing new phase transition behavior in 2D magnets.

Findings

Random fields induce a first-order phase transition.

The Curie temperature is reduced by random fields.

The phase transition persists under moderate external fields.

Abstract

In low-dimensional magnets, thermal agitation and spatial disorders generate strong spin fluctuations that suppress the long-range magnetic ordering. We develop an analytical equation for the equilibrium magnetization of two-dimensional magnets at finite temperatures in the presence of the random magnetic field. We find that the random field induces a first-order phase transition in addition to the reduced Curie temperature. The first-order phase transition persists even in the presence of the moderate external magnetic field.