Dynamic Skyrmion-Mediated Switching of Perpendicular MTJs: Feasibility Analysis of Scaling to 20 nm With Thermal Noise
Dynamic Skyrmion-Mediated Switching of Perpendicular MTJs: Feasibility Analysis of Scaling to 20 nm With Thermal Noise
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DOI：
10.1109/ted.2020.3011659
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发表时间：
2020-09-01
影响因子：
3.1
通讯作者：
Atulasimha, Jayasimha
中科院分区：
文献类型：
--
作者：
Rajib, Md Mahadi;Misba, Walid Al;Atulasimha, Jayasimha
在受限几何形状中产生和湮灭斯格明子的一种方法是使用电压控制磁各向异性（VCMA）。先前的研究表明，在存在室温热噪声和晶粒各向异性变化的情况下，通过创建并随后湮灭中间斯格明子态，可以实现垂直磁隧道结（p-MTJ）软层中从“上”到“下”状态的鲁棒压控铁磁反转。然而，当缩小到 20 nm 时，热噪声可能会消灭斯格明子，例如，通过将核心随机移动到纳米结构的边界。在这项工作中，我们研究了三种不同尺寸的 p-MTJ，特别是横向尺寸为 100、50 和 20 nm 的 p-MTJ，并研究了随着尺寸减小开关行为的变化。特别是，我们表明，虽然在存在热扰动的情况下，斯格明子介导的铁磁体开关在横向尺寸接近 20 nm 的情况下是可行的，但在横向尺寸接近 20 nm 时所需的 VCMA 和 Dzyaloshinskii-Moriya 相互作用 (DMI) 的大值仅在理论上进行了预测，迄今为止尚未通过实验证明。
One method of creating and annihilating skyrmions in confined geometries is to use voltage-controlled magnetic anisotropy (VCMA). The previous study shows that robust voltage-controlled ferromagnetic reversal from "up" to "down" state in the soft layer of a perpendicular magnetic tunnel junction (p-MTJ) can be achieved by creating and subsequently annihilating an intermediate skyrmion state in the presence of room temperature thermal noise and anisotropy variation across grains. However, when scaling to 20 nm, thermal noise can annihilate the skyrmions, for example, by randomly moving the core toward the boundary of the nanostructure. In this work, we study three p-MTJs of different dimensions, specifically lateral dimensions of 100, 50, and 20 nm and investigate the change in switching behavior as the dimension is decreased. In particular, we show that while skyrmion-mediated switching of ferromagnets in the presence of thermal perturbation is feasible down to lateral dimensions similar to 20 nm, the large values of VCMA and Dzyaloshinskii-Moriya interaction (DMI) needed at similar to 20 nm lateral dimensions have only been theoretically predicted and are yet to be experimentally demonstrated to date.