The double helices are found to host highly coupled textures. Credit: Claire Donnelly.
Scientists have used state-of-the-art 3D printing and microscopy to provide a new glimpse of what happens when taking magnets to three-dimensionals on the nanoscale.
The international team led by Cambridge University's Cavendish Laboratory used an advanced 3D printing technique to create magnetic double helices, which twist around one another, combining curvature, chirality, and strong magnetic field interactions between the helices. The scientists discovered that the magnetic double helices produce a new type of texture in the magnetic field, something that had never been seen before, opening the door to the next generation of magnetic devices. The results are published in a journal.
Magnetic devices impact many different parts of our societies, magnets are used for data storage and computing. Magnetic computing devices are close to their limit in two-dimensional systems. There is growing interest in moving to three dimensions, where higher densities can be achieved with 3D nanowire architectures, and three-dimensional geometries can change the magnetic properties.
Stuart Parkin proposed a technology called racetrack memory, which has been the subject of a lot of work. The idea is to store digital data in the magnetic domain walls of nanowires to produce information storage devices with high reliability, performance and capacity, said the study's first author from Cambridge's Cavendish Laboratory.
"But until now, this idea has always been very difficult to realize, because we need to be able to make three-dimensional magnetic systems and we also need to understand the effect of going to three dimensions on both the magnetisation and the magnetic field."
We have been working on developing new methods to visualize three-dimensional magnetic structures, like a magnetic resonance image in a hospital. 3D printing for magnetic materials was developed by us.
The only beamline that can offer soft X-ray laminography is the PolLux beamline of the Swiss Light Source. The 3D DNA structure leads to a different texture in the magnetisation compared to what is seen in 2D. The walls are highly coupled, and as a result, they are able to change shape. These walls attract one another and form bonds similar to the base pairs in DNA because of the 3D structure.
"We found that the 3D structure leads to interesting topological nanotextures in the magnetisation, where we are relatively used to seeing suchtextures, and also in the magnetic stray field, which revealed exciting new nanoscale field configurations!" he said.
The ability to pattern the magnetic field at this length scale allows us to understand how far we can go with patterning these magnetic fields. If we can control those magnetic forces on the small side, we can get the same degree of control as we have in two dimensions.
The texture of the double helix forms strong bonds between the helices, which makes it fascinating. The swirls around these bonds form in the magnetic field.
The full potential of going from two to three dimensions in terms of the magnetic field will be explored by Donnelly and her team from the universities of Glasgow, Zaragoza, Oviedo, and Vienna.
"These strongly bonding textures in the magnetic helices promise highly robust motion and could be a potential carrier of information," said Fernandez-Pacheco. This new potential to pattern the magnetic field at the nanoscale could offer new possibilities for particle trapping, as well as smart materials.
Nature Nanotechnology has more information on the nature of magnetic field textures. www.nature.com/articles/s41565-021-01027-7
Nature Nanotechnology journal has information.
The world of patterns in the magnetic field was revealed by 3D printednanomagnets.
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