| 研究実績の概要 |
Skyrmions are topologically protected entities in magnetic materials which have the potential to be used in spintronics for information storage and processing. However, Skyrmions in ferromagnets have some intrinsic difficulties which must be overcome to use them for spintronic applications, such as the inability to move straight along current. We show that Skyrmions can also be stabilized and manipulated in antiferromagnetic materials. An antiferromagnetic Skyrmion is a compound topological object with a similar but of opposite sign spin texture on each sublattice, which e.g. results in a complete cancellation of the Magnus force. We find that the composite nature of antiferromagnetic Skyrmions gives rise to different dynamical behavior, both due to an applied current and temperature effects [Phys. Rev. Lett. 116, 147203 (2016)].
Another achievement is related to the study of the domain wall dynamics in a magnetoelectric antiferromagnet and its implications for magnetoelectric memory applications [Appl. Phys. Lett. 108, 132403 (2016)]. We found that the domain wall mobility has a maximum as a function of the electric field due to the gyrotropic coupling induced by it. We show that in materials such as Cr2O3 the major drawbacks for device implementation can be overcome by applying a small in-plane shear strain, which blocks the domain wall precession. A split-gate scheme is proposed for the domain-wall controlled bit element; its extension to multiple-gate linear arrays can offer advantages in memory density, programmability, and logic functionality.
|
