Hayakawa K, Kanai S, Funatsu T, Igarashi J, Jinnai B, Borders W A, Ohno H, Fukami S
Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai 980-8577, Japan.
Division for the Establishment of Frontier Sciences, Organization for Advanced Studies, Tohoku University, Sendai 980-8577, Japan.
Phys Rev Lett. 2021 Mar 19;126(11):117202. doi: 10.1103/PhysRevLett.126.117202.
We study the timescale of random telegraph noise (RTN) of nanomagnets in stochastic magnetic tunnel junctions (MTJs). From analytical and numerical calculations based on the Landau-Lifshitz-Gilbert and the Fokker-Planck equations, we reveal mechanisms governing the relaxation time of perpendicular easy-axis MTJs (p-MTJs) and in-plane easy-axis MTJs (i-MTJs), showing that i-MTJs can be made to have faster RTN. Superparamagnetic i-MTJs with small in-plane anisotropy and sizable perpendicular effective anisotropy show relaxation times down to 8 ns at negligible bias current, which is more than 5 orders of magnitude shorter than that of typical stochastic p-MTJs and about 100 times faster than the shortest time of i-MTJs reported so far. The findings give a new insight and foundation in developing stochastic MTJs for high-performance probabilistic computers.
我们研究了随机磁性隧道结（MTJ）中纳米磁体的随机电报噪声（RTN）的时间尺度。基于朗道-里夫希茨-吉尔伯特方程和福克-普朗克方程进行的分析和数值计算，我们揭示了控制垂直易轴MTJ（p-MTJ）和面内易轴MTJ（i-MTJ）弛豫时间的机制，表明可以使i-MTJ具有更快的RTN。具有小面内各向异性和可观垂直有效各向异性的超顺磁性i-MTJ在可忽略的偏置电流下显示弛豫时间低至8纳秒，这比典型的随机p-MTJ短超过5个数量级，并且比迄今为止报道的i-MTJ的最短时间快约100倍。这些发现为开发用于高性能概率计算机的随机MTJ提供了新的见解和基础。
