Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.
Graduate School of Information Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Sci Rep. 2022 Dec 15;12(1):21651. doi: 10.1038/s41598-022-26018-z.
A new research topic in spintronics relating to the operation principles of brain-inspired computing is input-driven magnetization dynamics in nanomagnet. In this paper, the magnetization dynamics in a vortex spin-torque oscillator driven by a series of random magnetic field are studied through a numerical simulation of the Thiele equation. It is found that input-driven synchronization occurs in the weak perturbation limit, as found recently. As well, chaotic behavior is newly found to occur in the vortex core dynamics for a wide range of parameters, where synchronized behavior is disrupted by an intermittency. Ordered and chaotic dynamical phases are examined by evaluating the Lyapunov exponent. The relation between the dynamical phase and the computational capability of physical reservoir computing is also studied.
自旋电子学中一个与脑启发计算的工作原理相关的新研究课题是纳米磁体中的输入驱动磁化动力学。本文通过对 Thiele 方程的数值模拟，研究了一系列随机磁场驱动下的涡旋自旋振荡器中的磁化动力学。研究发现，在弱扰动极限下会出现输入驱动同步，这是最近才发现的。此外，在广泛的参数范围内，还会新发现涡旋芯动力学中的混沌行为，其中同步行为被间歇性所破坏。通过评估 Lyapunov 指数来检查有序和混沌动力学相。还研究了动力学相与物理存储计算的计算能力之间的关系。
