Enhanced spin transfer torque in platinum/ferromagnetic-metal structures by optimizing the platinum thickness

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:496

Article

Xue, Jianshu¹  Guo, Yaping¹  Wang, Ledong¹  Dong, Yanan¹  Chen, Yanxue¹  Tian, Yufeng¹  Yan, Shishen¹  Bai, Lihui¹ 

[1] Shandong Univ, Sch Phys, State Key Lab Crystal Mat, 27 Shandanan Rd, Jinan 250100, Shandong, Peoples R China

关键词: Spin transfer torque;    Spin Hall effect;    Rashba effect;    Harmonic Hall measurement;   

DOI  :  10.1016/j.jmmm.2019.165932

来源: Elsevier

【 摘 要 】

Spin transfer torque (STT) driven by a charge current plays a key role in magnetization switching in heavy-metal/ferromagnetic-metal structures. The SIT efficiency defined by the ratio between the effective field due to STT and the current density, is required to be improved to reduce energy compulsions in the STT-based spin-tronic devices. In this work, using the harmonic Hall measurement method, we experimentally studied the STT efficiency in platinum(Pt)/FM structures as a function of the Pt thickness. We found that the SIT efficiency strongly depends on the Pt thickness and reaches a maximum value of 4.259 mT/(10(6) A/cm(2)) for the 1.8-nmthickness Pt sample. This result indicates that competition between spin Hall effect (SHE) and Rashba effect as well as spin diffusion process across the Pt layer determines the Pt thickness for the maximum STT efficiency. We demonstrated the role played by the spin diffusion besides the spin current generation mechanisms in improvement of the SIT efficiency, which is helpful in designing STT-based devices.

【 授权许可】

Free