Rigorous determination of the ground-state phases and thermodynamics in an Ising-type multiferroic Ca3CoMnO6 chain

TL;DR

This paper exactly determines the ground-state phases and thermodynamics of an Ising-type multiferroic Ca3CoMnO6 chain, revealing magnetic interactions, phase transitions, and their relation to electric polarization.

Contribution

It introduces an elastic diatomic Ising spin-chain model with axial-next-nearest-neighbor interaction and employs exact methods to analyze ground states and thermodynamics.

Findings

Nearest-neighbor magnetic coupling is antiferromagnetic.

System exhibits a 1/3 magnetization plateau during transitions.

Multiple magnetic phase transitions under external magnetic field.

Abstract

To understand the collinear-magnetism-driven ferroelectricity in multiferroic Ca3CoMnO6 compound, we have established an elastic diatomic Ising spin-chain model with axial-next-nearest-neighbor interaction to describe its magnetoelectric properties. By employing magneto-phonon decoupling and transfer-matrix method, the possible ground-state configurations and thermodynamic behaviors of the system have been exactly determined. From the perspective of the ground-state configuration, we analyze the computational results and make a detail comparison with experimental data. The parameter relation for the appearance of electric polarization has been discussed. Our data indicate that the magnetic coupling between nearest-neighbor spin pair is antiferromagnetic rather than ferromagnetic. The system under the driven of external magnetic field undergoes a different series of transitions from the up-up-down-down spin configuration to the up-down-up state with peculiar 1/3 magnetization plateau, then to the up-up-up-down state, and finally saturated at up-up-up-up state.