Magnetic monopoles and toroidal moments in LuFeO$_3$ and related compounds

TL;DR

This paper proposes a mechanism for the emergence of magnetic monopolar and toroidal orders in LuFeO3 and related compounds, linking magnetic frustration, trimerization, and observable neutron scattering signatures.

Contribution

It introduces a novel mechanism for magnetic monopolar and toroidal order formation in hexagonal ferrites, supported by microscopic modeling and neutron scattering simulations.

Findings

Identification of neutron scattering signatures of monopolar and toroidal orders

Demonstration of non-reciprocal magnon propagation

Linking magnetic frustration with exotic magnetic orders

Abstract

Magnetic monopoles and toroidal order are compelling features that have long been theorized but remain elusive in real materials. Multiferroic hexagonal ferrites are an interesting realization of frustrated triangular lattice, where magnetic order is coupled to ferroelectricity and trimerization. Here we propose a mechanism, through which magnetic monopolar and toroidal orders emerge from the combination of 120$^\circ$ antiferromagnetism and trimerization, present in hexagonal manganites and ferrites. The experimentally observable signatures of magnetic monopolar and toroidal orders are identified in the inelastic neutron scattering cross section, simulated from a microscopic model of LuFeO3. The non-reciprocal magnon propagation is demonstrated.