中国物理B ›› 2024, Vol. 33 ›› Issue (4): 47503-047503.doi: 10.1088/1674-1056/ad1a88

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Wedge-shaped HfO2 buffer layer-induced field-free spin—orbit torque switching of HfO2/Pt/Co structure

Jian-Hui Chen(陈建辉)1, Meng-Fan Liang(梁梦凡)1, Yan Song(宋衍)1, Jun-Jie Yuan(袁俊杰)1, Meng-Yang Zhang(张梦旸)2, Yong-Ming Luo(骆泳铭)1,†, and Ning-Ning Wang(王宁宁)1   

  1. 1 School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
    2 Covestro(Shanghai) lnvestment Co., Ltd, Shanghai 200126, China
  • 收稿日期:2023-09-25 修回日期:2023-12-26 接受日期:2024-01-04 出版日期:2024-03-19 发布日期:2024-03-22
  • 通讯作者: Yong-Ming Luo E-mail:ymluo@hdu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 12274108), the Natural Science Foundation of Zhejiang Province, China (Grant Nos. LY23A040008 and LY23A040008), and the Basic Scientific Research Project of Wenzhou, China (Grant No. G20220025).

Wedge-shaped HfO2 buffer layer-induced field-free spin—orbit torque switching of HfO2/Pt/Co structure

Jian-Hui Chen(陈建辉)1, Meng-Fan Liang(梁梦凡)1, Yan Song(宋衍)1, Jun-Jie Yuan(袁俊杰)1, Meng-Yang Zhang(张梦旸)2, Yong-Ming Luo(骆泳铭)1,†, and Ning-Ning Wang(王宁宁)1   

  1. 1 School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
    2 Covestro(Shanghai) lnvestment Co., Ltd, Shanghai 200126, China
  • Received:2023-09-25 Revised:2023-12-26 Accepted:2024-01-04 Online:2024-03-19 Published:2024-03-22
  • Contact: Yong-Ming Luo E-mail:ymluo@hdu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 12274108), the Natural Science Foundation of Zhejiang Province, China (Grant Nos. LY23A040008 and LY23A040008), and the Basic Scientific Research Project of Wenzhou, China (Grant No. G20220025).

摘要: Field-free spin—orbit torque (SOT) switching of perpendicular magnetization is essential for future spintronic devices. This study demonstrates the field-free switching of perpendicular magnetization in an HfO2/Pt/Co/TaOx structure, which is facilitated by a wedge-shaped HfO2 buffer layer. The field-free switching ratio varies with HfO2 thickness, reaching optimal performance at 25 nm. This phenomenon is attributed to the lateral anisotropy gradient of the Co layer, which is induced by the wedge-shaped HfO2 buffer layer. The thickness gradient of HfO2 along the wedge creates a corresponding lateral anisotropy gradient in the Co layer, correlating with the switching ratio. These findings indicate that field-free SOT switching can be achieved through designing buffer layer, offering a novel approach to innovating spin—orbit device.

关键词: spin—orbit torque, field-free switching, HfO2 buffer layer

Abstract: Field-free spin—orbit torque (SOT) switching of perpendicular magnetization is essential for future spintronic devices. This study demonstrates the field-free switching of perpendicular magnetization in an HfO2/Pt/Co/TaOx structure, which is facilitated by a wedge-shaped HfO2 buffer layer. The field-free switching ratio varies with HfO2 thickness, reaching optimal performance at 25 nm. This phenomenon is attributed to the lateral anisotropy gradient of the Co layer, which is induced by the wedge-shaped HfO2 buffer layer. The thickness gradient of HfO2 along the wedge creates a corresponding lateral anisotropy gradient in the Co layer, correlating with the switching ratio. These findings indicate that field-free SOT switching can be achieved through designing buffer layer, offering a novel approach to innovating spin—orbit device.

Key words: spin—orbit torque, field-free switching, HfO2 buffer layer

中图分类号:  (Spin-orbit effects)

  • 75.70.Tj
85.75.-d (Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields) 75.70.-i (Magnetic properties of thin films, surfaces, and interfaces)