Pt/Ni双层器件中的异常自旋霍尔磁电阻效应  

Abnormal Spin Hall Magnetoresistance Effect in Pt/Ni Bilayer System

作　　者：王宇豪 郭方准[1] WANG Yuhao;GUO Fangzhun(School of Mechanical Engineering,Dalian Jiaotong University,Dalian,Liaoning 116028,China)

机构地区：[1]大连交通大学机械工程学院,辽宁大连116028

出　　处：《自动化应用》2024年第17期220-223,共4页Automation Application

摘　　要：系统研究了Pt/Ni双层体系中的磁电阻效应。在Pt层厚度为1 nm的Pt/Ni双层器件中,随着Ni层厚度的增加,自旋霍尔磁电阻变化率的符号由正变负。由界面控制与Ni单层器件信号的对比分析可知,界面效应并不是导致Pt/Ni体系中的负自旋霍尔磁电阻变化率的主导机制。负磁电阻变化率主要由Ni层中的几何尺寸效应引起,而正磁电阻变化率则主要由界面自旋轨道耦合效应引起,这2种效应之间的竞争是自旋霍尔磁电阻符号变化的根本原因。深入探讨了双层膜结构中负自旋霍尔磁电阻变化率的起源与演化,以加强对类似结构中磁电阻现象的理解,同时为新型自旋器件的开发和应用拓宽了视野。For spintronics,the non-magnetic/ferromagnetic bilayer structure is a fundimental device configuration,serving as a traditional framework for exploring various spin-related mechanisms,especially the charge-spin conversion.This work systematically investigates magnetoresistance in a series of Pt/Ni bilayer devices.An abnormal negative spin-hall magnetoresistance(SMR)is reported within this system.It is found that the SMR ratio sign is tied to the thickness of the Ni layer,transitioning from positive to negative as the Ni layer thickness increases.After analyzing together with reference samples,several common mechanisms are distinguished and evaluated.To suppress the bulk contribution of Pt layer to the SMR and limit the potential mechanism to interface and Ni layer-related effects,the Pt layer thickness is initially set to 1 nm.By comparing with Ni monolayer devices,the negative SMR and its sign change feature are ascribed to the competition between the interfacial spin-orbit coupling effect and the geometrical size effect,offering positive and negative contributions to SMR ratio,respectively.This investigation into the origins and evolution of spin Hall magnetoresistance in bilayer structures not only deepens the understanding of magnetoresistance phenomena in similar structures but also broadens the scope for further development and application of spin-based devices.

关 键 词：自旋电子学 自旋霍尔磁电阻 几何尺寸效应 界面自旋轨道耦合效应 

分 类 号：O469[理学—凝聚态物理]