R&D: Improved Racetrack Structure for Transporting Skyrmion

Nature Scientific Reports has published an article written by P. Lai, College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, China, Department of Physics and Electronic science, Aba Teachers University, Wenchuan 623002, China, G. P. Zhao, College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, China, Collaborative Innovation Center for Shanxi Advanced Permanent Materials and Technology, Linfen 041004, China, H. Tang, N. Ran, S. Q. Wu, College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, China , J. Xia, X. Zhang, and Y. Zhou, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518172, China.

Figure 1: Schematic of the proposed skyrmion racetrack,
where the middle part is made of CoPt,
whilst the two symmetrical edge parts are made
of a material with a higher anisotropy with a width denoted by w_edge.

Abstract: “Magnetic skyrmions are promising building blocks for next generation data storage due to their stability, small size and extremely low currents to drive them, which can be used instead of traditional magnetic domain walls to store information as data bits in metalic racetrack memories. However, skyrmions can drift from the direction of electron flow due to the Magnus force and thus may annihilate at the racetrack edges, resulting in the loss of information. Here we propose a new skyrmion-based racetrack structure by adding high-K materials (materials with high magnetic crystalline anisotropy) at the edges, which confines the skyrmions in the center region of the metalic racetrack efficiently. This design can overcome both the clogging and annihilation of skyrmions according to our micromagnetic simulation, which occur normally for skyrmions moving on a racetrack under small and large driving currents, respectively. Phase diagrams for skyrmion motion on the proposed racetrack with various values of current density and racetrack edge width have been calculated and given, showing that skyrmions can be driven at a high speed (about 300 m/s) in the racetrack under relatively smaller driving currents. This design offers the possiblity of building an ultrafast and energy-efficient skyrmion transport device.”