Spin-lattice model of Magneto-electric Transitions in RbCoBr$_3$

TL;DR

This paper uses advanced Monte Carlo simulations of a spin-lattice Ising model to explain magnetic and dielectric transitions in RbCoBr$_3$, highlighting the importance of spin-lattice coupling and introducing a new simulation algorithm.

Contribution

It introduces a novel Monte Carlo algorithm that accelerates simulations of quasi-one-dimensional frustrated systems and applies it to RbCoBr$_3$ to explain experimental observations.

Findings

Spin-lattice coupling is crucial for ferrimagnetic order growth.

The model accurately reproduces magnetic and dielectric transition sequences.

New Monte Carlo method enhances simulation efficiency for frustrated systems.

Abstract

Extensive Monte Carlo simulations are performed to analyze a recent neutron diffraction experiment on a distorted triangular lattice compound RbCoBr$_3$. We consider a spin-lattice model, where both spin and lattice are Ising variables. This model explains well successive magnetic and dielectric transitions observed in the experiment. The exchange interaction parameters and the spin-lattice coupling are estimated. It is found that the spin-lattice coupling is important to explain the slow growth of a ferrimagnetic order. The present simulations were made possible by developing a new Monte Carlo algorithm, which accelerates slow Monte Carlo dynamics of quasi-one-dimensional frustrated systems.