Quantitative and three-dimensional observations by electron holography

Abstract

This paper reviews advances in quantitative and three-dimensional (3D) observations by electron holography. Electron holography provides quantitative electron wave information regarding electromagnetic fields in and around samples at the micron to atomic scale. Spatial resolution and quantitative precision in electron holography have been improved by hardware- and software-type aberration corrections. This has led to observations of atomic-resolution electrostatic potential that enable electrons to be counted on catalyst nanoparticles. Furthermore, combinations of hardware and software-type aberration correction have enabled magnetic-field observations at the level of individual lattice planes. This paper also details how the merits of quantitative observation have been utilized in three-dimensional observations of electrostatic potentials and magnetic fields and how tomographic electron holography has unveiled the three-dimensional magnetic-field distributions in skyrmions.