Symmetry-based phenomenological model for magnon transport in a multiferroic

TL;DR

This paper develops a symmetry-based phenomenological model to understand and predict magnon spin currents in multiferroic materials like BiFeO$_3$, highlighting the role of magnetic and polar symmetries in controlling magnon transport.

Contribution

It introduces a novel phenomenological model that links the symmetries of multiferroics to magnon spin transport, based on experimental data from BiFeO$_3$ and its derivatives.

Findings

Symmetry considerations allow for switchable magnon spin transport.

The model explains the origin of magnon currents in complex magnetic textures.

Experimental data supports the symmetry-based predictions.

Abstract

Magnons carriers of spin information can be controlled by electric fields in the multiferroic BiFeO$_3$ (BFO), a milestone that brings magnons closer to application in future devices. The origin of magnon-spin currents in BFO, however, is not fully understood due to BFO's complicated magnetic texture. In this letter, we present a phenomenological model to elucidate the existence of magnon spin currents in generalized multiferroics by examining the symmetries inherent to their magnetic and polar structures. This model is grounded in experimental data obtained from BFO and its derivatives, which informs the symmetry operations and resultant magnon behavior. By doing so, we address the issue of symmetry-allowed, switchable magnon spin transport in multiferroics, thereby establishing a critical framework for comprehending magnon transport within complex magnetic textures.