Disentangling Magnetic and Grain Contrast in Polycrystalline FeGe Thin Films Using Four-Dimensional Lorentz Scanning Transmission Electron Microscopy

  title={Disentangling Magnetic and Grain Contrast in Polycrystalline 
 Thin Films Using Four-Dimensional Lorentz Scanning Transmission Electron Microscopy},
  author={Kayla X. Nguyen and Xiyue S. Zhang and Emrah Turgut and Michael C. Cao and Jack Glaser and Zhen Chen and Matthew J. Stolt and Celesta S. Chang and Yu Tsun Shao and Song Jin and Gregory D. Fuchs and David A. Muller},
  journal={Physical Review Applied},
The study of nanoscale chiral magnetic order in polycrystalline materials with a strong DzyaloshinkiiMoriya interaction (DMI) is interesting for the observation of magnetic phenomena at grain boundaries and interfaces. This is especially true for polycrystalline materials, which can be grown using scalable techniques and whose scalability is promising for future device applications. One such material is sputterdeposited B20 FeGe on Si, which has been actively investigated as the basis for low… 
2 Citations

Figures from this paper

Angstrom-Scale Imaging of Magnetization in Antiferromagnetic Fe$_2$As via 4D-STEM

We demonstrate a combination of computational tools and experimental 4D-STEM methods to image the local magnetic moment in antiferromagnetic Fe 2 As with 6 angstrom spatial resolution. Our techniques

Lorentz electron ptychography for imaging magnetic textures beyond the diffraction limit

Nanoscale spin textures, especially magnetic skyrmions, have attracted intense interest as candidate high-density and power-efficient information carriers for spintronic devices1,2. Facilitating a



Towards control of the size and helicity of skyrmions in helimagnetic alloys by spin-orbit coupling.

The correlation between skyrmion helicity and crystal chirality in alloys of helimagnets Mn(1-x)Fe(x)Ge with varying compositions is reported on by Lorentz transmission electron microscopy and convergent-beam electron diffraction over a broad range of compositions.

High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy

A hybrid pixel array detector adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy, which can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution.

Jointed magnetic skyrmion lattices at a small-angle grain boundary directly visualized by advanced electron microscopy

Observations of the interaction of magnetic skyrmions with a small-angle GB in a thin film of FeGe1−xSix strongly suggest the flexible nature of individual magnets, and also the significance of defect engineering for future device applications.

Anisotropic Superexchange Interaction and Weak Ferromagnetism

A theory of anisotropic superexchange interaction is developed by extending the Anderson theory of superexchange to include spin-orbit coupling. The antisymmetric spin coupling suggested by

A thermodynamic theory of “weak” ferromagnetism of antiferromagnetics

Near room-temperature formation of a skyrmion crystal in thin-films of the helimagnet FeGe.

The formation of SkX close to room temperature in thin-films of the helimagnet FeGe with magnetic chirality inversion of the SkX across lattice twin boundaries will pave a new path to designing quantum-effect devices based on the controllable skyrmion dynamics.

Real-space observation of a two-dimensional skyrmion crystal

Real-space imaging of a two-dimensional skyrmion lattice in a thin film of Fe0.5Co 0.5Si using Lorentz transmission electron microscopy reveals a controlled nanometre-scale spin topology, which may be useful in observing unconventional magneto-transport effects.

Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction

A simplified quantum theoretical interpretation of DPC is presented, which enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright-field detectors.

Chiral magnetic excitations in FeGe films

Although chiral magnetic materials have emerged as a potential ingredient in future spintronic memory devices, there are few comprehensive studies of magnetic properties in scalably grown thin films.

Theory and practice of electron diffraction from single atoms and extended objects using an EMPAD.

A simple quantum mechanical model is used to explain the general and asymptotic limits for the probability distribution in both real and reciprocal space of long-range and short-range potentials.