Imaging of magnetic and electric fields by electron microscopy

Abstract

Nanostructured materials become more and more a part of our daily life, partly as self-assembled particles or artificially patterned. These nanostructures often possess intrinsic magnetic and/or electric fields which determine (at least partially) their physical properties. Therefore it is important to be able to measure these fields reliably on a nanometre scale. A rather common instrument for the investigation of these fields is the transmission electron microscope as it offers high spatial resolution. The use of an electron microscope to image electric and magnetic fields on a micron down to sub-nanometre scale is treated in detail for transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEM). The formation of contrast is described for the most common imaging modes, the specific advantages and disadvantages of each technique are discussed and examples are given. In addition, the experimental requirements for the use of the techniques described are listed and explained.

Visualizing quantum phenomena at complex oxide interfaces: An atomic view from scanning transmission electron microscopy

“…Lorentz TEM [108,109], electron holography [110,111], 4-D STEM / differential phase contrast (DPC)-STEM [112,113], and electron energy-loss magnetic chiral dichroism (EMCD) [112][113][114] represent the state-of-the-art techniques to detect magnetic textures in complex materials. Lorentz TEM has been employed directly to resolve the skyrmion spin texture in Fe0.5Co0.5Si thin films [117] and studied magnetic transition from stripe to bubble state in PbFe12O19 [112]. Electron holography has identified the amplified magnetization near the antiphase boundary defects [111].…”

Parallel Mode Differential Phase Contrast in Transmission Electron Microscopy, I: Theory and Analysis

“…The theory of electron optics and its application to the study of electromagnetic fields is well developed (DeGraef, 2001; Beleggia & Zhu, 2003; Beleggia et al, 2003 c ; Zweck, 2016). In the following, we cover the parts most relevant to the electron phase change on encountering electromagnetic potentials.…”

Irradiation stability and induced ferromagnetism in a nanocrystalline CoCrCuFeNi highly-concentrated alloy

“…Differential phase contrast (DPC) was used to assess physical aspects of the FeCo nanoprecipitates formed after irradiation plus annealing at 773K and also solely due to annealing at 773 K (see [49][50][51][52][53][54] for details on DPC microscopy). It is worth emphasising that such FeCo nanoprecipitates also formed after irradiation and subsequent annealing at 573 K (the row d in the figure 4).…”