Resonance spin-transfer torque in ferromagnetic/normal-metal/ferromagnetic spin-valve structure of topological insulators

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:492

Article

Zare, Moslem¹ 

[1] Univ Yasuj, Dept Phys, Yasuj 75914353, Iran

关键词: Topological insulator;    Spin current;    Resonance spin-transfer torque;    Ferromagnetic/normal/ferromagnetic;   

DOI  :  10.1016/j.jmmm.2019.165605

来源: Elsevier

【 摘 要 】

We theoretically study the spin current and spin-transfer torque (STT) generation in a conventional spin-valve hybrid structure of type ferromagnetic/normal metal/ferromagnetic (FM/NM/FM) made of topological insulator (TI), in which a gate voltage is attached to the normal layer. The spin current densities and the STTs are oscillatory functions of the chemical potential and the length of the NM spacer. We investigate the penetration of the spin-transfer torque into the right ferromagnetic layer and show that, unlike the case of graphene FM/NM/ FM junction, the spin-transfer torque in TI is very sensitive to the chemical potential of the NM region. As an important result, all STT components can be controlled with varying the chemical potential of the NM spacer and/or varying the magnetization directions. Interestingly, both the resonance spin current and the resonance spin-transfer torque appear for energies determined from a resonance equation. By increasing the chemical potential of the NM spacer the amplitude of the SIT oscillations decreases, while in the heavily doped regime, there are intervals of the chemical potential over which the spin current and the spin-transfer torque become zero. As a highlighting feature, we found that a beating pattern of the STT oscillations, occurs for some certain values of the chemical potential of the NM spacer. Our findings could open new perspectives for applications in spin-transfer torque magnetic random access memory (STT-MRAM) devices based on TI.

【 授权许可】

Free