Magnon Planar Hall Effect and Anisotropic Magnetoresistance in a Magnetic Insulator

TL;DR

This paper demonstrates the magnon planar Hall effect and anisotropic magnetoresistance in a magnetic insulator, revealing a 5% difference in magnon conductivity depending on the magnetization direction at room temperature.

Contribution

It reports the first experimental observation of magnon analogs of the planar Hall effect and anisotropic magnetoresistance in a magnetic insulator at room temperature.

Findings

Magnon conductivity varies by about 5% depending on magnetization orientation.

Majority of devices show higher magnon conductivity perpendicular to magnetization.

Electrical and thermal magnon injection methods effectively measure anisotropic effects.

Abstract

Electrical resistivities can be different for charge currents travelling parallel or perpendicular to the magnetization in magnetically ordered conductors or semiconductors, resulting in the well-known planar Hall effect and anisotropic magnetoresistance. Here, we study the analogous anisotropic magnetotransport behavior for magnons in a magnetic insulator Y$_{3}$Fe$_{5}$O$_{12}$. Electrical and thermal magnon injection, and electrical detection methods are used at room temperature with transverse and longitudinal geometries to measure the magnon planar Hall effect and anisotropic magnetoresistance, respectively. We observe that the relative difference between magnon current conductivities parallel and perpendicular to the magnetization, with respect to the average magnon conductivity, i.e. $|(\sigma_{\parallel}^{\textrm{m}}-\sigma_{\perp}^{\textrm{m}})/\sigma_{0}^{\textrm{m}}|$ , is approximately 5% with the majority of the measured devices showing $\sigma_{\perp}^{\textrm{m}}>\sigma_{\parallel}^{\textrm{m}}$.