摘要
自旋纳米振荡器是一种新型的自旋电子学器件,与传统的半导体振荡器相比,具有尺寸小、调频范围宽、易集成等优点.以往的自旋纳米振荡器通常是由自旋极化电流通过自旋转移力矩效应进行驱动.本文提出一种可能的由自旋波驱动的纳米振荡器的设计方案.我们的微磁学模拟结果表明,圆柱形铁磁纳米线中的钉扎畴壁在自旋波的驱动下可以发生持续进动.畴壁进动频率在GHz量级,与透射自旋波振幅呈正相关,与材料的阻尼系数呈负相关.畴壁的进动方向由自旋波的传播方向及畴壁类型决定.基于磁子自旋转移力矩效应建立的理论模型可以定量解释圆柱形纳米线中自旋波驱动的钉扎畴壁的动力学性质.这一发现原则上为铁磁纳米结构中自旋波的输出提供了一条新的途径,对于发展未来自旋电子学器件具有潜在的应用价值.
Spin waves(SWs)and domain walls(DWs)have been two prominent research fields in the history of magnetism,which remain active in unfolding spintronics.In the past decades,rich novel dynamic effects have been revealed in the exploration of SWs and DWs in magnetic nanostructures,promising important applications in new-generation magnetic devices.Due to the absence of Joule heat,SWs are considered as candidates for information carriers with ultra-low power consumption.DW dynamics at the nanoscale,besides its fundamental interests,also bears significance in terms of technology applications.A spin nano-oscillator is a new type of spintronic device,which has advantages such as small size,wide frequency modulation range,and easy integration compared to traditional semiconductor oscillators.Former spin nanooscillators are usually driven by spin polarized electric current via the so-called spin-transfer torque effect.In a typical spin nano-oscillator,the magnetization of the free layer of a spin valve(SV)or a magnetic tunneling junction(MTJ)is driven by electric currents to sustain a continuous precession,with the damping of the system compensated by the current.Highly tunable microwave signals can be generated during the oscillation.In a current-driven DW nano-oscillator proposed recently,the free layer of a SVor MTJ is replaced by a transverse DW pinned in a ferromagnetic nanowire,which oscillates periodically subject to a spin-transfer torque exerted by a current passing through the DW.It has been pointed out that SWs also carry spin currents and thus spin angular momentum,which can as well be transferred to local magnetic structures,such as DWs,during its transportation.This effect is referred to as the magnonic spin-transfer torque.Previous studies have been focused on ferromagnetic thin-films,in which a translational motion of the DW is found to be induced by the electric current.In this work,we study the SW-driven DW dynamics in cylindrical nanowires.If thin enough,a stable transverse DW can form in a ferromagnetic n
作者
范明明
颜明
Mingming Fan;Ming Yan(Department of Physics,Shanghai University,Shanghai 200444,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2024年第21期3185-3190,共6页
Chinese Science Bulletin
基金
国家自然科学基金(11774218)
上海市高温超导重点实验室(14DZ2260700)资助。
关键词
自旋波
畴壁
微磁学模拟
磁子自旋传递力矩
纳米振荡器
spin waves
domain walls
micromagnetic simulations
magnonic spin-transfer torque
nano-oscillators
