A skyrmion is a vortex-like spin structure with a diameter of several to several-hundreds of nanometers, consisting of hundreds to tensof-thousands of spins in a magnet.
We directly observed their aggregate in a crystalline form for
the first time by transmission electron microscopy. When all the spins within a skyrmion are collected at one point, the spin direction covers the sphere exactly once. In such a case that the spin direction overs
the sphere an integer number of times, the spin structure is said to be topological. Since the skyrmion structure has been proposed in elementary particle physics half a century ago, the observed magnetic particles are called skyrmions. Their topological property brings unique physical properties through interactions with electrons.
For example, they can be driven with a small amount of electrical power, which possibly enables an ultra-low power-consumption information processing device in the future. Furthermore, like a huge magnetic  field applied, a skyrmion can bend the trajectory of moving electrons, which can cause phenomena that exceed the conventional wisdom of electromagnetics.

Topological magnetic particle skyrmion opens up new electromagnetism
2019
Production: Professor Yoshinori Tokura, Department of Applied Physics, School of Engineering, The University of Tokyo
Collection: Department of Applied Physics, School of Engineering, The University of Tokyo
Topological character of a skyrmion (left top). When all the spins within a skyrmion are collected at one point, the spin direction covers the sphere exactly once. Schematic illustration of a skyrmion (left bottom). Crystal state of densely-packed skyrmions (right).