Optical spin–orbit torque in Pd/Co bilayers

초록

Optical spin generation in heavy metals can be transferred to adjacent ferromagnetic metals to induce an optical spin–orbit torque (OSOT). Owing to ultrafast timescale of OSOT, it can be employed to excite fast dynamics of ferromagnet, such as precession and spin waves. In this work, we investigate OSOT in a bilayer of Pd/Co, where Pd is responsible for the optical spin generation. Analyzing the frequency and amplitude of the OSOT-driven dynamics of Co, we determined the effective quantum efficiency of 4 % and spin diffusion length of 10 nm of Pd. The quantum efficiency is nearly independent of wavelength in the range from 530 nm to 785 nm. © 2025 Elsevier B.V.

키워드