Enhancing the spin transfer torque in magnetic tunnel junctions by ac modulation
Abstract
The phenomenon of spin transfer torque (STT) has attracted a great deal of interests due to its promising prospects in practical spintronic devices. In this paper, we report a theoretical investigation of STT in a noncollinear magnetic tunnel junction under ac modulation based on the nonequilibrium Green's function formalism, and derive a closed-formulation for predicting the time-averaged STT. Using this formulation, the ac STT of a carbon-nanotube-based magnetic tunnel junction is analyzed. Under ac modulation, the low-bias linear (quadratic) dependence of the in-plane (out-of-plane) torque on bias still holds, and the dependence on the noncollinear angle is maintained. By photon-assisted tunneling, the bias-induced components of the in-plane and out-of-plane torques can be enhanced significantly, about 12 and 75 times, respectively. Our analysis reveals the condition for achieving optimized STT enhancement and suggests that ac modulation is a very effective way for electrical manipulation of STT.
Cite
@article{arxiv.1705.02579,
title = {Enhancing the spin transfer torque in magnetic tunnel junctions by ac modulation},
author = {Xiaobin Chen and Chenyi Zhou and Zhaohui Zhang and Jingzhe Chen and Xiaohong Zheng and Lei Zhang and Can-Ming Hu and Hong Guo},
journal= {arXiv preprint arXiv:1705.02579},
year = {2017}
}
Comments
23 pages, 5 figures