Nutational Spin Pumping and Dissipation
The paper investigates magnetization dynamics at terahertz frequencies using an inertial Landau-Lifshitz-Gilbert equation. It discovers a novel nutational damping torque and spin-pumping mechanism arising from a dissipative term proportional to Gilbert damping and inertial relaxation time. This leads to nutational spin pumping that is quadratic in the drive frequency, detectable through various experimental techniques.