Dresden 2017 – wissenschaftliches Programm
MA 23.7: Vortrag
Dienstag, 21. März 2017, 11:15–11:30, HSZ 403
Relativistic theory of magnetic inertia in ultrafast spin dynamics — •Ritwik Mondal, Marco Berritta, Ashis K. Nandy, and Peter M. Oppeneer — Department of Physics and Astronomy, Uppsala University, Sweden
The influence of possible magnetic inertia effects has recently drawn attention in ultrafast magnetization dynamics and switching1. Here we derive rigorously a theory 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 2nd order time-derivative of magnetization in the dynamical equation of motion. Thus, the inertia damping is a higher order spin-orbit coupling effect, as compared to the Gilbert damping2. It is therefore expected to play a role only on ultrashort timescales (sub-picoseconds)3. We also show that the Gilbert damping and intrinsic inertia damping are related to one another4 through the imaginary and real parts of the magnetic susceptibility tensor respectively.
1A. V. Kimel et al., Nature Phys. 5, 727 (2009). 2R. Mondal, M. Berritta and P. M. Oppeneer Phys. Rev. B 94, 144419 (2016). 3M.-C. Ciornei, J. M. Rubí and J.-E. Wegrowe, Phys. Rev. B 83, 020410(R) (2011). 4M. Fähnle, D. Steiauf and C. Illg, Phys. Rev. B 84, 172403 (2011).