Skyrmions – small whirls in the magnetisation of magnetic materials – can have a diameter of less than 100nm. They may be important for the future of magnetic data storage and information processing if they can be moved rapidly and reliably along nanowires or other structures.
The researchers found skyrmions follow a complex trajectory and continue to move after external excitation is removed. The team say this effect will be especially important if a skyrmion is to be moved to a selected position, as would be necessary in a future memory device.
The skyrmions were prepared using small magnetic discs. "When we apply a specific external magnetic field, the magnetisation in these discs creates whirls," said Dr Benjamin Krüger from JGU. Skyrmions were then excited by a magnetic field pulse to trace their motion. "The measurements show that skyrmions move on a very complex trajectory – a hypocycloid," Dr Krüger added.
Because they move on such a curved trajectory means that they must possess inertia. "This effect has not been taken into account until now, but it is important for the development of small magnetic memories," explained Professor Mathias Kläui.
