振荡磁场驱动亚铁磁畴壁动力学研究  

Dynamics of ferrimagnetic domain wall driven by oscillating magnetic field

作　　者：赵晨蕊 杨倩倩 焦距 唐政华[1] 秦明辉 ZHAO Chenrui;YANG Qianqian;JIAO Ju;TANG Zhenghua;QIN Minghui(Microelectronics and Optoelectronics Technology Key Laboratory of Hunan Higher Education,School of Physics and Electronic Electrical Engineering,Xiangnan University,Chenzhou 423000,China;Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials,South China Institute of Advanced Optoelectronics,South China Normal University,Guangzhou 510006,China)

机构地区：[1]湘南学院物理与电子电气工程学院,微电子与光电子技术湖南省高校重点实验室,郴州423000 [2]华南师范大学华南先进光电子研究院,广东省量子调控工程与材料重点实验室,广州510006

出　　处：《物理学报》2025年第3期222-229,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:U22A20117,52371243);广东省自然科学基金(批准号:2022A1515011727,2024A1515012665);湘南学院2021年度大学生创新项目资助的课题。

摘　　要：亚铁磁材料在角动量补偿点附近具有类比于反铁磁的超快动力学,且存在非零净自旋密度,其磁结构可以被传统磁性手段探测和调控,有望应用于新一代高性能自旋电子器件.有效调控亚铁磁畴壁动力学是当前自旋电子学领域的重要课题.本工作使用微磁学模拟研究了正弦波和方波振荡磁场驱动亚铁磁畴壁,从理论上揭示不同的振荡磁场会诱导出不同方式的畴壁运动.研究表明,具有非零净自旋角动量的畴壁面随振荡磁场振荡,正弦波磁场驱动亚铁磁畴壁的位移随时间单调增加,而方波磁场驱动畴壁位移随时间曲折增大.本工作系统探讨了亚铁磁畴壁速度与外部磁场和材料内部参数的关联,表明了同强度下的正弦波磁场具有更高的驱动效率,并揭示了相关物理机制,可以为未来的实验和自旋器件设计提供参考.Ferrimagnetic materials exhibit ultrafast dynamic behaviors similar to those of antiferromagnetic materials near the angular momentum compensation point,where a non-zero net spin density is maintained.This unique feature makes their magnetic structures detectable and manipulable by using traditional magnetic techniques,thus positioning ferrimagnetic materials as promising candidates for next-generation high-performance spintronic devices.However,effectively controlling the dynamics of ferrimagnetic domain walls remains a significant challenge in current spintronics research.In this work,based on the classic Heisenberg spin model,Landau-Lifshitz-Gilbert(LLG)simulation is used to investigate the dynamic behaviors of ferrimagnetic domain walls driven by sinusoidal wave periodic magnetic field and square wave periodic magnetic field,respectively.The results show that these two types of oscillating magnetic fields induce distinct domain wall motion modes.Specifically,the domain wall surface,which has nonzero net spin angular momentum,oscillates in response to the external magnetic field.It is found that the domain wall velocity decreases as the net spin angular momentum increases.Moreover,the displacement of the ferrimagnetic domain wall driven by a sinusoidal magnetic field increases monotonically with time,while the displacement driven by a square wave magnetic field follows a more tortuous trajectory over time.Under highfrequency field conditions,the domain wall displacement shows more pronounced linear growth,and the domain wall surface rotates linearly with time.In this work,how material parameters,such as net spin angular momentum,anisotropy,and the damping coefficient,influence domain wall dynamics is also explored.Specifically,increasing the anisotropy parameter(d_(2))or the damping coefficient(α)results in a reduction of domain wall velocity.Furthermore,the study demonstrates that,compared with the square wave magnetic fields,the sinusoidal magnetic fields drive the domain wall more efficiently,leading domai

关 键 词：畴壁动力学 自旋电子学 振荡磁场 亚铁磁体 

分 类 号：O469[理学—凝聚态物理]