激光诱导自旋阀结构的超快自旋动力学研究  

Research on ultrafast spin dynamics of laser-induced spin valve structures

作　　者：芦闻天 姚春伟 严志 袁喆 LU Wentian;YAO Chunwei;YAN Zhi;YUAN Zhe(Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education,Research Institute of Materials Science,School of Chemistry and Materials Science,Shanxi Normal University,Taiyuan 030031,China;Interdisciplinary Center for Theoretical Physics and Information Sciences,Institute of NanoelectronicDevicesand Quantum Computing,Fudan University,Shanghai 200433,China)

机构地区：[1]山西师范大学化学与材料科学学院,材料科学研究院,磁性分子与磁信息材料教育部重点实验室,太原030031 [2]复旦大学纳米电子器件与量子计算研究所,理论物理与信息科学交叉中心,上海200433

出　　处：《物理学报》2025年第6期264-270,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12404139);山西省自然科学基金(批准号:202203021212393)资助的课题.

摘　　要：超快退磁的发现提供了一种使用超短激光产生超快自旋流的新手段,从而可能更快地操纵材料磁性.然而,这一过程仍未被理解,尤其是超快自旋流在层间转移中的影响因素尚不明晰.本文利用超扩散自旋输运模型对Ni/Ru/Fe自旋阀结构体系的超快自旋输运机制进行了深入研究,尤其关注层间自旋转移效率对铁磁层超快磁动力学的影响.本研究计算出铁磁层在不同磁化排列下的退磁差异,并通过调节间隔层厚度,揭示出超快自旋输运在磁动力学中的关键作用.此外,还确定了热电子自旋流在间隔层中的自旋衰减长度.通过控制激光的薄膜吸收,进一步发现了能够引起铁磁层瞬态磁化增强的条件.这些结果对于理解热电子自旋流的输运机制具有重要意义,为未来控制超快自旋流提供了理论基础.The discovery of ultrafast demagnetization has provided a new means for generating ultrafast spin currents by using an ultrashort laser,potentially enabling faster manipulation of material magnetism.This has sparked research on the transport mechanisms of ultrafast spin currents.However,the basic processes are still poorly understood,especially the factors influencing interlayer spin transfer.In this work,a superdiffusive spin transport model is used to investigate the ultrafast spin transport mechanism in the Ni/Ru/Fe spin valve system,with a particular focus on how interlayer spin transfer affects the ultrafast magnetization dynamics of the ferromagnetic layer.First,by calculating the laser-induced magnetization dynamics of the Ni/Ru/Fe system under different magnetization alignments,the recent experimental findings are validated.Further analysis shows that reducing the thickness of the Ru spacer layer will significantly enhance the spin current intensity and increase the demagnetization difference in the Fe layer,confirming the key role of the hot electron spin current generated by the Ni layer in interlayer spin transport.In addition,the spin decay length of hot electron spin currents in the spacer Ru layer is determined to be approximately 0.5 nm.This work also shows that laserinduced transient magnetization enhancement can be achieved by adjusting the relative laser absorption in the films.These results provide theoretical support for ultrafast magnetic control of future spin valve structures and contribute to the development of spintronics in high-speed information processing and storage applications.

关 键 词：自旋电子学 超快磁动力学 自旋极化输运 

分 类 号：O469[理学—凝聚态物理]