Enhancement of spin–orbit torque in sputtered BiSb-based perpendicular magnetic tunnel junctions for neuromorphic computing applications

IF 3.6 2区物理与天体物理 Q2 PHYSICS, APPLIED

Applied Physics Letters Pub Date : 2025-10-01 DOI:10.1063/5.0275455

S. Wu, G. J. Lim, F. N. Tan, T. L. Jin, C. C. I. Ang, E. K. Koh, S. H. Lee, K. J. Cheng, W. S. Lew

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引用次数: 0

Abstract

Topological insulators offer unique properties for generating high spin–orbit torque (SOT), promising to revolutionize magnetoresistive random-access memory with a low power consumption. In this work, BiSb is integrated into perpendicular magnetic tunnel junctions (pMTJs) to enable efficient SOT switching. By optimizing the BiSb thickness and introducing a Ta buffer layer, a threefold enhancement in damping-like SOT efficiency and a 60% reduction in switching current are achieved compared to the BiSb-free sample. X-ray diffraction measurements confirm the improved crystalline quality with increasing BiSb thickness, contributing to the enhanced spin current generation. The fabricated BiSb-pMTJs exhibit key neuromorphic functionalities, including gradual long-term potentiation/depression and sigmoidal resistance modulation under pulsed current. Utilizing these features, a three-layer artificial neural network is implemented based on experimentally extracted device behavior, achieving over 90% accuracy in handwritten digit recognition.

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用于神经形态计算应用的溅射铋基垂直磁隧道结的自旋轨道转矩增强

拓扑绝缘体为产生高自旋轨道转矩（SOT）提供了独特的性能，有望以低功耗彻底改变磁阻随机存取存储器。在这项工作中，BiSb被集成到垂直磁隧道结（pMTJs）中，以实现高效的SOT开关。通过优化铋厚度和引入Ta缓冲层，与无铋样品相比，类阻尼SOT效率提高了三倍，开关电流降低了60%。x射线衍射测量证实，随着铋厚度的增加，晶体质量得到改善，这有助于增强自旋电流的产生。制备的BiSb-pMTJs表现出关键的神经形态功能，包括脉冲电流下逐渐的长期增强/抑制和s型电阻调制。利用这些特征，基于实验提取的设备行为实现了三层人工神经网络，手写数字识别准确率达到90%以上。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Physics Letters 物理-物理：应用

CiteScore

6.40

自引率

10.00%

发文量

1821

审稿时长

1.6 months

期刊介绍： Applied Physics Letters (APL) features concise, up-to-date reports on significant new findings in applied physics. Emphasizing rapid dissemination of key data and new physical insights, APL offers prompt publication of new experimental and theoretical papers reporting applications of physics phenomena to all branches of science, engineering, and modern technology. In addition to regular articles, the journal also publishes invited Fast Track, Perspectives, and in-depth Editorials which report on cutting-edge areas in applied physics. APL Perspectives are forward-looking invited letters which highlight recent developments or discoveries. Emphasis is placed on very recent developments, potentially disruptive technologies, open questions and possible solutions. They also include a mini-roadmap detailing where the community should direct efforts in order for the phenomena to be viable for application and the challenges associated with meeting that performance threshold. Perspectives are characterized by personal viewpoints and opinions of recognized experts in the field. Fast Track articles are invited original research articles that report results that are particularly novel and important or provide a significant advancement in an emerging field. Because of the urgency and scientific importance of the work, the peer review process is accelerated. If, during the review process, it becomes apparent that the paper does not meet the Fast Track criterion, it is returned to a normal track.