Study of the low-temperature behavior of a disordered antiferromagnet with random fields by the parallel-tempering method

TL;DR

This study uses parallel-tempering simulations to explore the low-temperature phases of a disordered 3D antiferromagnetic Ising model with random fields, revealing distinct ordered and complex mixed phases depending on disorder strength.

Contribution

It applies the parallel-tempering method to analyze the low-temperature behavior of a disordered antiferromagnet with random fields, identifying new phase states.

Findings

Weak disorder leads to antiferromagnetic order.

Strong disorder results in a mixed phase with spin-glass characteristics.

Complex domain structures emerge at high disorder levels.

Abstract

The parallel-tempering method has been applied to numerically study the thermodynamic behavior of a three-dimensional disordered antiferromagnetic Ising model with random fields at spin concentrations corresponding to regions of both weak and strong structural disorder. An analysis of the low-temperature behavior of the model convincingly shows that in the case of a weakly disordered samples there is realized an antiferromagnetic ordered state, while in the region of strong structural disorder the effects of random magnetic fields lead to the realization of a new phase state of the system with a complex domain structure consisting of antiferromagnetic and ferromagnetic domains separated by regions of a spin-glass phase and characterized by a spinglass ground state.