Inertia in spin dynamics

Spin dynamics with inertia in metallic ferromagnets.

Toru Kikuchi and Gen Tatara

Phys. Rev. B 92, 184410 (2015)

(a) Without any magnetic field, the general motion of spin with finite inertia is a free precession motion, just like a spinning top. The spin Sn precesses around the total angular momentum j0. (b) When a constant magnetic field B is applied, the total angular momentum j0 precesses around B. Therefore the “free precession cone” in (a) precesses around B as a whole, which corresponds to the Larmor precession in the absence of the inertia. What was called the free precession in (a) is now called the nutation.