| In recent years,with the increasing demand for efficient and high-speed information storage devices,the research on magnetization dynamics in nanoscale systems has attracted extensive attention from scientists.One of the hot topics is the driving scheme and technology of ultrafast spin mechanics.It is found that the study of magnetization dynamics on ultrafast time scales(sub-picosecond to femtosecond)requires the extension of the Landau-Lifshitz-Gilbert equation.The extended new equation will include the inertial term,whose existence will lead to nutation of magnetization.Based on this,this paper mainly explores nutation resonance in ferromagnetic resonance spectrum.The paper includes the following content:First of all,the research background of inertia Landau-Lifshitz-Gilbert equation is introduced,and the origin of inertia term is described briefly.Secondly,the nutation resonance in ferromagnetic resonance spectrum with magnetic field applied is introduced.In this context,the optimal pulse required for the fastest reversal of magnetization after applying current when the inertial term exists is explored.In the last and most important part,nutation resonance in ferromagnetic resonance spectrum under ultrafast magnetics is studied.Under the same initial conditions,the equation is analyzed theoretically and simulated numerically by applying two different currents.Two angles describing the position of the magnetization intensity in spherical coordinates and the oscillation diagram of their first-order derivatives with time are given.In addition,the precession and nutation oscillations of each component of magnetization on long time scales and short time scales,as well as nutation formants caused by the inertial effect of alternating current excitation are analyzed in detail. |
