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 polarization is a unique and unambiguous signature of magnets and is important in spintronics, affecting thermodynamic properties such as the magnitude and sign of the spin Seebeck effect. However, it has never been directly measured in any material until this work. 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.
| Original language | English |
|---|---|
| Article number | 027201 |
| Journal | Physical Review Letters |
| Volume | 125 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jul 10 2020 |
Funding
We thank M. Böhm for his assistance during the experiments and S. Maekawa, M. Mori, and S. Shamoto for valuable discussions. This work was supported by the JSPS (Grants No. 16H04007, No. 17H05473, No. 19H04683, No. 17H06137, No. 16H02125, No. 19H00645, No. 25247056, No. 25220910, No. 26103006, No. 19K21031), ERATO “Spin Quantum Rectification Project” (No. JPMJER1402) from JST, the Graduate Program in Spintronics at Tohoku University and the Royal Society through a University Research Fellowship. Calculations were performed on ARC3, part of the High Performance Computing facilities at the University of Leeds, UK. J. M. T. was supported at Brookhaven by the Office of Basic Energy Sciences, U.S. Department of Energy, under Contract No. DE-SC0012704. Work at O. R. N. L. was supported by the U.S.-Japan Cooperative Program on Neutron Scattering.