Magnetic skyrmion is a difficult-to-describe nanoscale object. They can be thought of as spinning circles of magnetism.
These objects are expected to yield new microelectronic devices that can do much more. However, researchers need a more detailed understanding of skyrmions if they can be used reliably in computational devices, including quantum computers.
Scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have successfully captured 3D X-ray images of skyrmions that can characterize or measure the orientations of spins inside the whole object. The results open up new avenues for nanoscale metrology for spintronics devices.
Skyrmions are tiny, stable magnetic structures where the spin direction at the center points upward while it twists and points downward further out.
Their stability, speed, and resistance to disruption, known as “topological” properties, make them promising for carrying and storing information, similar to how electrons are used in current devices.
Peter Fischer, a senior researcher at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), said, “However, relying on the charge of the electron, as it is done today, comes with inevitable energy losses. Using spins will significantly lower the losses.”
While skyrmions have been primarily studied as 2D objects in theory, in real-world applications, such as electronics and silicon wafers, they exist in 3D. Researchers must understand their spin characteristics across the entire 3D structure to effectively use or even create custom skyrmions.
Raftery created a nanodisk from a thin magnetic layer provided by colleagues at Western Digital using the Molecular Foundry’s nanofabrication facility. To capture 3D tomographic images of the skyrmions, he traveled to Switzerland and utilized a novel imaging technique called magnetic X-ray laminography at the Swiss Light Source microscopy beamline.
Raftery said, “With X-ray laminography, you can reconfigure and reconstruct [the skyrmion] from many images and data. It was a process that took months, finally yielding a better understanding of skyrmion spin structures.”
Fischer said a full understanding of skyrmions’ 3D spin texture “opens opportunities to explore and tailor 3D topological spintronic devices with enhanced functionalities that cannot be achieved in two dimensions. “
Journal Reference:
- David Raftrey, Simon Finzio, and Peter Fischer. Quantifying the topology of magnetic skyrmions in three dimensions. Science Advances. DOI: 10.1126/sciadv.adp8615