arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1504.02252cond-mat.mes-hallcond-mat.mtrl-scicond-mat.str-el
收藏

无Skyrmion霍尔效应的磁性双层Skyrmion

Magnetic bilayer-skyrmions without skyrmion Hall effect

Xichao Zhang, Yan Zhou, Motohiko Ezawa

摘要:

由于Skyrmion的非平凡拓扑结构,其电磁场的产生可能会导致Skyrmion霍尔效应的产生,但由于Skyrmion在纳米轨道中的任何纵向运动都伴随着横向运动,因此这种效应可能会成为实际应用的障碍。这种效应的一个直接后果是,尽管它们具有拓扑保护,但在它们沿着纳米轨道的快速运动期间,在纳米轨道边缘处的skyrmions容易被破坏。在这里,我们提出了一个全新的解决方案,完全抑制这种斯基尔米恩霍尔效应,而不影响其拓扑性质的基础上的反铁磁耦合双层系统。我们发现,一对磁性skyrmions可以通过垂直电流注入成核在这样的双层系统或从电流驱动的畴壁对转换。一旦成核,skyrmion对可以通过电流引起的自旋力矩从垂直注入电流或面内电流移位。由于作用在每个skyrmion上的反作用力的抵消,skyrmion霍尔效应被完全抑制,导致skyrmion沿着电流方向的直线和快速运动。这一建议将通过引入双层自由度的系统的根本利益。此外,它提供了一种简单的方法来设计skyrmionic设备的传输特性,以实现所需的性能,使其非常有希望的实际应用,如超密度存储器和基于skyrmions的信息处理设备。

英文摘要:

Arising from emergent electromagnetic field of magnetic skyrmions due to their nontrivial topology, the skyrmion Hall effect might be a roadblock for practical applications since any longitudinal motions of skyrmions in nanotrack is accompanied by a transverse motion. A direct consequence of such an effect is easy destruction of skyrmions at the nanotrack edges during their fast motions along the nanotrack, despite their topological protection. Here we propose an entirely novel solution of completely inhibiting such skyrmion Hall effect without affecting its topological properties based on a antiferromagnetic-coupling bilayer system. We show that a pair of magnetic skyrmions can be nucleated in such a bilayer system through vertical current injection or converted from a current-driven domain-wall pair. Once nucleated, the skyrmion pair can be displaced through current-induced spin torque either from a vertical injected current or in-plane current. The skyrmion Hall effect is completely suppressed due to the cancellation of back-action forces acting on each individual skyrmion, resulting in a straight and fast motion of skyrmions along the current direction. This proposal will be of fundamental interests by introducing the bilayer degree of freedom into the system. Moreover, it provides an easy way to engineer the transport properties of the skyrmionic devices to achieve desired performance, making it highly promising for practical applications such as ultradense memory and information-processing devices based on skyrmions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑