Henning Ulrichs and Ilya Razdolski:
Phys. Rev. B 98, 054429 (2018), pp11;
In this paper, we discuss a micromagnetic modeling approach to describe the ultrafast spin-transfer torque excitation of coherent and incoherent magnons on the nanoscale. Implementing the action of a femtosecond spin current pulse entering an orthogonally magnetized thin ferromagnetic film, we reproduce recent experimental results and reveal the factors responsible for the unequal excitation efficiency of various spin waves. Our findings are in an excellent agreement with the results of an analytical description of spin-wave excitation based on classical kinetic equations. Furthermore, we suggest an experimental design allowing for the excitation of laterally propagating spin waves beyond the optical diffraction limit. Our findings demonstrate that the classical micromagnetic picture retains its predictive and interpretative power for modeling the reaction of the magnetization on dynamical stimuli that reside on femtosecond temporal and nanometer spatial scales.
The original publication is available by link DOI: 10.1103/PhysRevB.98.054429