Magnon planar Hall effect and anisotropic magnetoresistance in a magnetic insulator

Abstract

Electrical resistivities can be different for charge currents traveling 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 ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$. 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., $|({\ensuremath{\sigma}}_{\ensuremath{\parallel}}^{\mathrm{m}}\ensuremath{-}{\ensuremath{\sigma}}_{\ensuremath{\perp}}^{\mathrm{m}})/{\ensuremath{\sigma}}_{0}^{\mathrm{m}}|$, is approximately 5% with the majority of the measured devices showing ${\ensuremath{\sigma}}_{\ensuremath{\perp}}^{\mathrm{m}}>{\ensuremath{\sigma}}_{\ensuremath{\parallel}}^{\mathrm{m}}$.