中国物理B ›› 2023, Vol. 32 ›› Issue (4): 48504-048504.doi: 10.1088/1674-1056/aca7e9

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Ta thickness effect on field-free switching and spin-orbit torque efficiency in a ferromagnetically coupled Co/Ta/CoFeB trilayer

Zhongshu Feng(冯重舒)1, Changqiu Yu(于长秋)1,†, Haixia Huang(黄海侠)1, Haodong Fan(樊浩东)1, Mingzhang Wei(卫鸣璋)1, Birui Wu(吴必瑞)1, Menghao Jin(金蒙豪)1, Yanshan Zhuang(庄燕山)1, Ziji Shao(邵子霁)1, Hai Li(李海)1, Jiahong Wen(温嘉红)1, Jian Zhang(张鉴)2, Xuefeng Zhang(张雪峰)2, Ningning Wang(王宁宁)1, Sai Mu(穆赛)1, and Tiejun Zhou(周铁军)1,‡   

  1. 1 School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
    2 Second Affiliation Institute of Advanced Magnetic Materials, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
  • 收稿日期:2022-09-08 修回日期:2022-11-26 接受日期:2022-12-02 出版日期:2023-03-10 发布日期:2023-04-04
  • 通讯作者: Changqiu Yu, Tiejun Zhou E-mail:cqyu@hdu.edu.cn;tjzhou@hdu.edu.cn
  • 基金资助:
    Project supported by the ‘Pioneer’ and ‘Leading Goose’ Research and Development Program of Zhejiang Province, China (Grant No. 2022C01053), the National Natural Science Foundation of China (Grant Nos. 11874135, 12104119, and 12004090), Key Research and Development Program of Zhejiang Province, China (Grant No. 2021C01039), and Natural Science Foundation of Zhejiang Province, China (Grant Nos. LQ20F040005 and LQ21A050001).

Ta thickness effect on field-free switching and spin-orbit torque efficiency in a ferromagnetically coupled Co/Ta/CoFeB trilayer

Zhongshu Feng(冯重舒)1, Changqiu Yu(于长秋)1,†, Haixia Huang(黄海侠)1, Haodong Fan(樊浩东)1, Mingzhang Wei(卫鸣璋)1, Birui Wu(吴必瑞)1, Menghao Jin(金蒙豪)1, Yanshan Zhuang(庄燕山)1, Ziji Shao(邵子霁)1, Hai Li(李海)1, Jiahong Wen(温嘉红)1, Jian Zhang(张鉴)2, Xuefeng Zhang(张雪峰)2, Ningning Wang(王宁宁)1, Sai Mu(穆赛)1, and Tiejun Zhou(周铁军)1,‡   

  1. 1 School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
    2 Second Affiliation Institute of Advanced Magnetic Materials, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
  • Received:2022-09-08 Revised:2022-11-26 Accepted:2022-12-02 Online:2023-03-10 Published:2023-04-04
  • Contact: Changqiu Yu, Tiejun Zhou E-mail:cqyu@hdu.edu.cn;tjzhou@hdu.edu.cn
  • Supported by:
    Project supported by the ‘Pioneer’ and ‘Leading Goose’ Research and Development Program of Zhejiang Province, China (Grant No. 2022C01053), the National Natural Science Foundation of China (Grant Nos. 11874135, 12104119, and 12004090), Key Research and Development Program of Zhejiang Province, China (Grant No. 2021C01039), and Natural Science Foundation of Zhejiang Province, China (Grant Nos. LQ20F040005 and LQ21A050001).

摘要: Current induced spin-orbit torque (SOT) switching of magnetization is a promising technology for nonvolatile spintronic memory and logic applications. In this work, we systematically investigated the effect of Ta thickness on the magnetic properties, field-free switching and SOT efficiency in a ferromagnetically coupled Co/Ta/CoFeB trilayer with perpendicular magnetic anisotropy. We found that both the anisotropy field and coercivity increase with increasing Ta thickness from 0.15 nm to 0.4 nm. With further increase of Ta thickness to 0.5 nm, two-step switching is observed, indicating that the two magnetic layers are magnetically decoupled. Measurements of pulse-current induced magnetization switching and harmonic Hall voltages show that the critical switching current density increases while the field-free switching ratio and SOT efficiency decrease with increasing Ta thickness. Both the enhanced spin memory loss and reduced interlayer exchange coupling might be responsible for the βDL decrease as the Ta spacer thickness increases. The studied structure with the incorporation of a CoFeB layer is able to realize field-free switching in the strong ferromagnetic coupling region, which may contribute to the further development of magnetic tunnel junctions for better memory applications.

关键词: spin-orbit coupling, interlayer exchange-coupling, field-free switching

Abstract: Current induced spin-orbit torque (SOT) switching of magnetization is a promising technology for nonvolatile spintronic memory and logic applications. In this work, we systematically investigated the effect of Ta thickness on the magnetic properties, field-free switching and SOT efficiency in a ferromagnetically coupled Co/Ta/CoFeB trilayer with perpendicular magnetic anisotropy. We found that both the anisotropy field and coercivity increase with increasing Ta thickness from 0.15 nm to 0.4 nm. With further increase of Ta thickness to 0.5 nm, two-step switching is observed, indicating that the two magnetic layers are magnetically decoupled. Measurements of pulse-current induced magnetization switching and harmonic Hall voltages show that the critical switching current density increases while the field-free switching ratio and SOT efficiency decrease with increasing Ta thickness. Both the enhanced spin memory loss and reduced interlayer exchange coupling might be responsible for the βDL decrease as the Ta spacer thickness increases. The studied structure with the incorporation of a CoFeB layer is able to realize field-free switching in the strong ferromagnetic coupling region, which may contribute to the further development of magnetic tunnel junctions for better memory applications.

Key words: spin-orbit coupling, interlayer exchange-coupling, field-free switching

中图分类号:  (Magnetic devices)

  • 85.70.-w
75.60.Jk (Magnetization reversal mechanisms) 75.70.Tj (Spin-orbit effects)