Dynamics of Antiferromagnets Driven by Spin Current
Abstract
When a spin-polarized current flows through a ferromagnetic (FM) metal, angular momentum is transferred to the background magnetization via spin-transfer torques. In antiferromagnetic (AFM) materials, however, the corresponding problem is unsolved. We derive microscopically the dynamics of an AFM system driven by spin current generated by an attached FM polarizer, and find that the spin current exerts a driving force on the local staggered order parameter. The mechanism does not rely on the conservation of spin angular momentum, nor does it depend on the induced FM moments on top the AFM background. Two examples are studied: (i) A domain wall is accelerated to a terminal velocity by purely adiabatic effect where the Walker's break-down is avoided; and (ii) Spin injection modifies the AFM resonance frequency, and spin current injection triggers spin wave instability of local moments above a threshold.
Cite
@article{arxiv.1304.1284,
title = {Dynamics of Antiferromagnets Driven by Spin Current},
author = {Ran Cheng and Qian Niu},
journal= {arXiv preprint arXiv:1304.1284},
year = {2015}
}
Comments
5 pages (superlink for supplemental material is provided)