Hitachi’s holography electron microscope reveals the secrets of crystalline materials


By Dr. Tim Sandle
July 9, 2024

Amethyst is a violet variety of quartz. Image by Parent Géry - Own work, CC BY-SA 3.0

In a recent study published in the journal Nature, researchers have achieved a groundbreaking resolution of 0.47 nm using Hitachi’s holography electron microscope to visualize atomic-scale magnetic fields.

This advancement paves the way for new discoveries in materials science and significant improvements in electronics and energy generation. Through image acquisition and defocusing correction techniques, scientists have enables observations of atomic-scale magnetic fields to be made at never-before-seen resolution.

Electron holography microscopy is an advanced technique that can be used to visualize magnetic fields in materials at atomic resolution. In a recent study, researchers from Japan addressed some key limitations in this technique, achieving a groundbreaking resolution of 0.47 nanometres (nm) when imaging magnetic atomic lattices in a crystal. Prior to this breakthrough, the maximum resolution at which the magnetic field of atomic layers could be observed was limited to around 0.67 nm.

Key to the newly developed image acquisition technology are defocus correction algorithms. These enable scientists to visualize the magnetic fields of individual atomic layers within the crystalline solid. The technique implemented was able to correct for defocusing due to minor focus shifts by analysing reconstructed electron waves. The resulting images were free of residual aberrations, making the positions and phases of atoms easily discernible with magnetic field.

These efforts by the Japanese researchers could pave the way for scientific discoveries in materials science and notable sustainability improvements in electronics, energy generation, and other applied fields.

The main complexity was with developing a system to automate the control and tuning of the device during data acquisition. This served to significantly speed up the imaging process to a speed of 10,000 images over 8.5 hours.

These developments are important since many advances in electronic devices, catalysis, transportation, and energy generation have been made possible by the development and adoption of high-performance materials with tailored characteristics.

To test out the capabilities the researchers performed electron holography measurements on samples of Ba2FeMoO6, a layered crystalline material in which adjacent atomic layers have distinct magnetic fields.

Atom arrangement and electron behaviour are critical factors that dictate a crystalline material’s properties. For instance, the orientation and strength of magnetic fields right at the interface between different materials or atomic layers are particularly important.

The findings have been published in the journal Nature. The research paper is titled “Electron Holography Observation of Individual Ferrimagnetic Lattice Planes.”