LAUSR

Gilbert damping is of great importance for ultrahigh-speed spintronic devices, as it determines the magnetization dynamics of a ferromagnet. However, $a\phantom{\rule{0}{0ex}}b$ $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ determination of Gilbert damping is challenging, due to the many different mechanisms behind the phenomenon. The authors use scattering theory and extend the powerful torque method to calculate Gilbert damping, and then study several examples of a monolayer of $3d$ transition-metal ferromagnet atop a topological insulator. Surprisingly, Gilbert damping in such a system is boosted by about an order of magnitude, thanks to the spin-orbit coupling in the topological insulator.