Ni/Pt异质结界面的自旋阻塞效应  

Spin blocking effect at Ni/Pt heterojunction

作　　者：杜梦瑶 邱志勇 Du Meng-Yao;Qiu Zhi-Yong(Key Laboratory of Materials Modification by Laser,Ion and Electron Beams,Ministry of Education,School of Materials Science and Engineering,Dalian University of Technology,Dalian 116000,China)

机构地区：[1]大连理工大学材料科学与工程学院,三束材料改性教育部重点实验,大连116000

出　　处：《物理学报》2023年第5期349-354,共6页Acta Physica Sinica

基　　金：国家自然科学学基金(批准号:11874098,52171173)资助的课题。

摘　　要：相比于电荷流的高功耗,自旋流可以高效地传输能量与信息的同时避免焦耳热的产生,因此基于自旋流的电子器件成为未来电子信息器件研发的重要方向之一.自旋流及其输运现象的相关研究是自旋电子学器件的开发基础.本文着眼于铁磁金属镍(Ni)与非磁重金属(Pt)构建的异质结结构,研究了异质结界面的自旋输运特性,发现其对扩散自旋流的全阻塞效应.本工作以基于钇铁石榴石(yttrium iron garnet,YIG)的YIG/Ni/Pt三层器件开展,采用自旋泵浦技术激发扩散自旋流注入到镍中,同时检测与分析器件中的逆自旋霍尔电压,并与YIG/Ni双层器件中的信号进行对比分析.结果证明YIG/Ni/Pt三层器件中的铂金属层仅起分流作用而对逆自旋霍尔电流无贡献,即镍层中的扩散自旋流被阻塞于Ni/Pt异质结界面.本工作加深了对界面处自旋流输运的认识,铁磁性金属/非磁重金属自旋流阻塞界面的发现也为自旋电子器件的设计及新功能开发提供了新的思路与手段.Spin current,the flow of spin angular momentum,can carry and transport energy and/or information without generating Joule heating,which makes spin-based devices become one of the potential aspects for the next-generation information processing devices.It is important to investigate the generation,transport,and detection of spins for developing spin-based devices,in which the spin transport and its related phenomena attract ongoing interest due to the complex interactions between spins and condensed matter system.Here,spin transport phenomenon is studied at a heterojunction consisting of ferromagnetic metal nickel and nonmagnetic heavy metal platinum,where transport spins are found to be totally blocked.Two series of spin-pumping devices,i.e.the yttrium iron garnet(YIG)/Ni/Pt trilayer devices and the contrastive YIG/Ni bilayer devices,are made in this work.The YIG serves as a substrate and spin-pump layer,on which nickel film and platinum film are deposited by a dc magnetron sputtering system.Spin currents are generated from YIG and injected into nickel layers by spin pumping technology.The voltage signals corresponding to the inverse spin Hall effect are detected and analyzed comparatively for both YIG/Ni/Pt trilayer device and YIG/Ni bilayer device.It is found that the platinum layers in YIG/Ni/Pt trilayer devices act only as charge current shunting but do not contribute to the spin-charge conversion.This implies that the spin current cannot transport through the Ni/Pt interface even when the nickel layer is as thin as 1 nm,in other words,the spin current is blocked at the Ni/Pt interface.Our result proposes a heterojunction that can block transport spins totally,which has never been discussed before,and the present study may expand the views and promote the development of spin-based devices.

关 键 词：自旋流 异质结界面 自旋阻塞 自旋泵浦 

分 类 号：O469[理学—凝聚态物理]