Purely antiferromagnetic frustrated Heisenberg model in spin ladder compound BaFe$_2$Se$_3$

TL;DR

This study investigates the spin dynamics of BaFe$_2$Se$_3$ using neutron scattering and theoretical modeling, revealing a purely antiferromagnetic frustrated Heisenberg model that explains its magnetic order and potential multiferroic properties.

Contribution

It introduces a novel purely antiferromagnetic frustrated Heisenberg model for BaFe$_2$Se$_3$, providing new insights into its magnetic behavior and multiferroic potential.

Findings

Describes the block magnetic order in BaFe$_2$Se$_3$

Proposes a magnetic Heisenberg model with only frustrated antiferromagnetic couplings

Explains the origin of stripe-like magnetic instability under pressure

Abstract

The spin dynamics in the block magnetic phase of the iron-based ladder compound \bfs\ has been studied by means of single crystal inelastic neutron scattering. Using linear spin wave theory and Monte-Carlo simulations, our analysis points to a magnetic Heisenberg model with effective frustrated antiferromagnetic couplings only, able to describe both the exotic block order and its dynamics. This new and purely antiferromagnetic picture offers a fruitful perspective to describe multiferroic properties but also understand the origin of the stripe-like magnetic instability observed under pressure as well as in other parent compounds with similar crystalline structure.