Imaging Precessional Motion of the Magnetization Vector

Abstract

We report on imaging of three-dimensional precessional orbits of the magnetization vector in a magnetic field by means of a time-resolved vectorial Kerr experiment that measures all three components of the magnetization vector with picosecond resolution. Images of the precessional mode taken with submicrometer spatial resolution reveal that the dynamical excitation in this time regime roughly mirrors the symmetry of the underlying equilibrium spin configuration and that its propagation has a non-wavelike character. These results should form the basis for realistic models of the magnetization dynamics in a largely unexplored but technologically increasingly relevant time scale.

Scalable parallel micromagnetic solvers for magnetic nanostructures

“…The magnetization dynamics under short field pulses have been investigated in saturated NiFe disks [128] and in closure domains in Co disks [129]. However, the magnetization dynamics of the magnetic vortex state in thin Permalloy disks is markedly different from those in the uniformly magnetized state and also from the spin-waves observed in thin magnetic films.…”

“…The characteristic switching time depends on the reversal mode and is usually in the nanosecond regime. The magnetization reversal excites many spin-excitation modes (spin waves), whose understanding is important to determine the field dependent spin instability regions, where spontaneous or thermally-assisted magnetization reversal might occur [127].The magnetization dynamics under short field pulses have been investigated in saturated NiFe disks [128] and in closure domains in Co disks [129]. However, the magnetization dynamics of the magnetic vortex state in thin Permalloy disks is markedly different from those in the uniformly magnetized state and also from the spin-waves observed in thin magnetic films.…”

Phase Coherent Precessional Magnetization Reversal in Microscopic Spin Valve Elements

“…The use of the pronounced precession initiated by fast rising magnetic field pulses (2,3,4,5) is currently discussed as a new route towards ultra fast magnetization reversal in future magnetic storage applications. Such precessional reversal promises high energy efficiency together with ultra fast reversal times reaching the fundamental limit of a half precession period (6,7,8,9,10,11).…”

Exploring nanomagnetism with soft X-ray microscopy

“…Magnetism on the nanometer scale and its spin dynamics on a nsec to fsec time scale is currently a scientfically highly attractive topic [1,2] since it addresses both fundamental magnetic lengh scales such as magnetic exchange lengths in the sub-10nm range [3] and interesting time scales of magnetism such as precessional and relaxation phenomena, domain wall and vortex dynamics [4][5][6]. The fundamental time scale in magnetism is given by the time required to transfer energy and momentum from the electronic into the spin system [7], which aims e.g.…”