Magnon currents excited by the spin Seebeck effect in ferromagnetic EuS thin films
M. Xochitl Aguilar-Pujol, Sara Catalano, Carmen González‐Orellana, Witold Skowroński, Juan M. Gómez‐Pérez, Maxim Ilyn, Celia Rogero, Marco Gobbi, Luis E. Hueso, Fèlix Casanova
Abstract
A magnetic insulator is an ideal platform to propagate spin information by exploiting magnon currents. However, until now, most studies have focused on ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ (YIG) and a few other ferri- and antiferromagnetic insulators, but not on pure ferromagnets. In this study, we demonstrate that magnon currents can propagate in ferromagnetic insulating thin films of EuS. By performing both local and nonlocal transport measurements in 18-nm-thick films of EuS using Pt electrodes, we detect magnon currents arising from thermal generation by the spin Seebeck effect. By comparing the dependence of the local and nonlocal signals with the temperature (30 K) and magnetic field (9 T), we confirm the magnon transport origin of the nonlocal signal. Finally, we extract the magnon diffusion length in the EuS film $(\ensuremath{\sim}140\phantom{\rule{0.16em}{0ex}}\mathrm{nm})$, a short value in good correspondence with the large Gilbert damping measured in the same film.