3D Electron Microscopy Reveals Hidden Magnetic Structures for Spintronics

Three-dimensional electron microscopy is making magnetic structures visible in ways that conventional imaging could not. For Xiuzhen Yu, director of the Electronic States Microscopy Research Team at Japan’s RIKEN Center for Emergent Matter Science, that shift matters because the shape and motion of electron spins could eventually support information technologies that use less power than conventional electronics.

Electronics typically encode and carry information through moving electric charge. Spintronics also draws on electron spin, a property that can form intricate patterns inside magnetic materials. Those patterns may offer new ways to store or process information, but turning them into working technology depends on understanding how they form, how stable they are, and how researchers can control them.

From predicted patterns to direct images

Yu’s work on skyrmions illustrates how microscopy can change what researchers are able to ask. A skyrmion is a vortex-like arrangement of spins that was first proposed theoretically. Before scientists could image one directly, small-angle neutron diffraction had identified a hexagonal skyrmion lattice in an alloy of manganese and silicon. That result provided evidence for the structure, but it did not show the twists in the spins themselves.

The diffraction finding encouraged Yu to pursue real-space imaging in actual materials. In 2009, she used Lorentz transmission electron microscopy to observe nanometer-scale skyrmions in Fe₀.₅Co₀.₅Si, a helimagnet whose electron spins form a spiral pattern. The experiment took place at 25 K, an ultralow temperature.

As Yu applied a small magnetic field, a bright dot appeared on the microscope monitor. Raising the field brought more dots into view. They arranged themselves into a hexagonal lattice, allowing the team to watch the pattern emerge rather than infer it from indirect measurements. Yu later became the first to directly observe an individual skyrmion with an electron microscope, a milestone that helped open the way to studying more complex spin configurations.

Because researchers had already developed a strong theoretical account of skyrmions, interpreting the observed structures was relatively straightforward once they could be seen. The harder task was extending imaging beyond two dimensions. Some magnetic textures have internal arrangements that a flat image cannot capture.

Mapping spin in three dimensions

Yu and her colleagues spent several years developing an electron tomography method based on differential phase-contrast microscopy. It reconstructs intrinsic three-dimensional vector fields inside magnetic materials at nanometer-scale resolution. The approach makes it possible to map how spins are oriented through a sample, providing a more complete view of the structures than a two-dimensional image can offer.

With this technique, researchers can examine magnetic features including skyrmion and antiskyrmion strings, surface magnetic vortices, and other topological spin textures. These structures had been predicted theoretically, but direct real-space views were unavailable. Tomography now lets researchers inspect their internal arrangements and consider how those arrangements relate to the material’s larger magnetic behavior.

Among the structures Yu has studied, hopfions stand out for their linked three-dimensional spin topology. A two-dimensional image cannot represent that topology fully. Reconstructing the spins in three dimensions makes features that were previously inaccessible available for direct study, connecting the geometry of a magnetic texture with the physics that produces it.

That ability to see a structure in detail is a research tool, not yet a device capability. Still, the images can help scientists test how magnetic interactions produce particular arrangements and how those arrangements respond to changes in their environment. Better understanding of that behavior is a necessary step toward determining whether topological textures can carry or process information reliably.

Heat as a way to control magnetic textures

Yu’s research also points to heat flow as a possible means of controlling topological spin structures. The work showed that heat, as well as electric current, can drive a transformation between skyrmions and antiskyrmions. That finding suggests researchers may be able to change the topology of a magnetic texture using small amounts of energy.

For future spintronic devices, thermal control could add another route for manipulating spins. The practical value will depend on whether researchers can produce the desired transformation consistently and understand how it behaves across real materials. The result offers a specific direction for further investigation: studying how heat currents affect the formation and conversion of these structures.

Before skyrmions can become practical information carriers, researchers need to establish how well they tolerate temperature changes, material defects, and other disturbances. They also need to learn how the textures move under electric currents, magnetic fields, and heat, and how reliably they can be created, manipulated, and erased with low energy use.

Those questions matter for proposed applications such as memory devices, where skyrmions’ small size and topological protection could support high-density, low-power data storage. Complex spin textures may also have a role in physical reservoir computing, including neuromorphic or brain-inspired information processing. These remain potential applications; their feasibility depends on mastering the textures’ stability and control.

Studying dynamics and sustaining research

Yu’s next research goal is to combine time-resolved Lorentz transmission electron microscopy with microwave excitation. That combination would let the team investigate how topological spin textures change over time and explore associated quantum phenomena. Adding time-resolved observation to three-dimensional imaging could help researchers connect a texture’s internal structure with its behavior under external excitation.

Yu received a 2026 Wiley Women in Science award. The awards were held in March at the Institute of Physics, Chinese Academy of Sciences, and recognized nine women researchers. The program is supported by the journal Advanced Physics Research. Its organizers say the awards aim to encourage future researchers and support a more inclusive scientific community.

Yu has also described research funding and the balance between work and family life as persistent challenges across her career. Her advice to young women considering research is to stay committed through major life changes, including having and raising a young child, while looking for ways to work efficiently and sustain their interest in science.

The near-term value of Yu’s work lies in making complex magnetic textures observable and measurable. As researchers learn how those structures respond to heat, fields, and other stimuli, they’ll have a firmer basis for deciding which ones can be controlled reliably enough for future spintronic technologies.