Lorentz microscopy and off-axis electron holography of magnetic skyrmions in FeGe

Abstract

Magnetic skyrmions are vortex-like spin structures that are of great interest scientifically and for applications in low-power mag-netic memories. The nanometer size and complex spin structure require high-resolution and quantitative experimental methods to study the physical properties of skyrmions. Here, we illustrate how Lorentz TEM and off-axis electron holography can be used to study the spin textures of magnetic skyrmions in the noncentrosymmetric B20-type helimagnet FeGe as a function of temperature and applied magnetic field. By reversing the magnetic field inside the microscope, the switching mechanism of the skyrmion lattice at 240 K is followed, showing a transition of the skyrmion lattice to the helical structure before the anti-skyrmion lattice is formed.