Observation of the Magnon Hall Effect

TL;DR

This paper reports experimental evidence of the magnon Hall effect in an insulating ferromagnet, showing that spin excitations can produce a thermal Hall effect influenced by spin-orbit interactions, expanding understanding of heat transport in magnetic materials.

Contribution

It provides the first experimental evidence of the magnon Hall effect and links it to the Dzyaloshinskii-Moriya interaction influencing spin wave propagation.

Findings

Evidence of anomalous thermal Hall effect caused by magnons

Dzyaloshinskii-Moriya interaction influences magnon propagation

Magnon Hall effect observed in pyrochlore lattice ferromagnet

Abstract

The Hall effect usually occurs when the Lorentz force acts on a charge current in a conductor in the presence of perpendicular magnetic field. On the other hand, neutral quasi-particles such as phonons and spins can carry heat current and potentially show the Hall effect without resorting to the Lorentz force. We report experimental evidence for the anomalous thermal Hall effect caused by spin excitations (magnons) in an insulating ferromagnet with a pyrochlore lattice structure. Our theoretical analysis indicates that the propagation of the spin wave is influenced by the Dzyaloshinskii-Moriya spin-orbit interaction, which plays the role of the vector potential as in the intrinsic anomalous Hall effect in metallic ferromagnets.