2017/03/20 by Ritwik Mondal, Marco Berritta, Ashis K. Nandy +1 · 4 citations
Physics and Astronomy · #cond-mat.other
paper · pdf · doi:10.1103/physrevb.96.024425
published as Phys. Rev. B 96, 024425 (2017) · 8 pages, 1 figure
arxiv created 2017/03/20 · arxiv updated 2017/07/26
The influence of possible magnetic inertia effects has recently drawn attention in ultrafast magnetization dynamics and switching. Here we derive rigorously a description of inertia in the Landau-Lifshitz-Gilbert equation on the basis of the Dirac-Kohn-Sham framework. Using the Foldy-Wouthuysen transformation up to the order of 1/c4 gives the intrinsic inertia of a pure system through the 2\rm nd order time-derivative of magnetization in the dynamical equation of motion. Thus, the inertial damping I is a higher order spin-orbit coupling effect, ∼ 1/c4, as compared to the Gilbert damping Γ that is of order 1/c2. Inertia is therefore expected to play a role only on ultrashort timescales (sub-picoseconds). We also show that the Gilbert damping and inertial damping are related to one another through the imaginary and real parts of the magnetic susceptibility tensor respectively.