Observation of the Magnon Polarization

TL;DR

This paper reports the experimental measurement of magnon polarization in Y3Fe5O12 using polarized neutron scattering, revealing its ferrimagnetic nature and implications for spintronics and thermodynamic properties.

Contribution

It introduces a method to measure magnon polarization directly and confirms theoretical predictions with experimental data.

Findings

Magnon polarization can be directly measured using polarized neutron scattering.

Both signs of magnon polarization are observed in Y3Fe5O12.

Experimental results agree well with atomistic simulations.

Abstract

We measure the mode-resolved direction of the precessional motion of the magnetic order, i.e., magnon polarization, via the chiral term of inelastic polarized neutron scattering spectra. The magnon polarisation is important in spintronics, affecting thermodynamic properties such as the magnitude and sign of the spin Seebeck effect. The observation of both signs of magnon polarization in Y3Fe5O12 also gives direct proof of its ferrimagnetic nature. The experiments agree very well with atomistic simulations of the scattering cross section.