不同厚度Cr中间层对Gd/FeCo薄膜磁电阻效应转变的影响  

Influence of Cr interlayer with different thickness on transition of magnetoresistance effect of Gd/FeCo thin films

作　　者：张艺玮 宋恒博 李小燕 孙丽[1] 刘晓莹 寇朝霞 张栋[3] 费红阳 赵志斌 翟亚 Zhang Yi-Wei;Song Heng-Bo;Li Xiao-Yan;Sun Li;Liu Xiao-Ying;Kou Zhao-Xia;Zhang Dong;Fei Hong-Yang;Zhao Zhi-Bin;Zhai Ya(College of Physics and Electronic Engineering,Hainan Normal University,Haikou 571158,China;School of Physics,Southeast University,Nanjing 211189,China;School of Physics Science and Information Engineering,Liaocheng University,Liaocheng 252059,China)

机构地区：[1]海南师范大学物理与电子工程学院,海口571158 [2]东南大学物理学院,南京211189 [3]聊城大学物理科学与信息工程学院,聊城252059

出　　处：《物理学报》2022年第21期302-310,共9页Acta Physica Sinica

基　　金：海南省自然科学基金(批准号:2019RC169,117109,114008);国家自然科学基金(批准号:12164016,11364015);海南省科协青年科技英才科技创新(批准号:QCXM201810);海南省激光技术与光电功能材料重点实验室资助的课题。

摘　　要：磁电阻作为表征自旋阀结构最具代表性的特征之一,是研究多层膜层间耦合作用的重要研究手段.稀土/磁性过渡金属通过耦合和界面效应诱导室温下稀土具有磁性,插入中间非磁金属层通过调控层间耦合作用实现自旋阀结构将有利于拓展稀土在自旋电子学领域的应用.通过分析具有不同Cr层厚度(t_(Cr))的Gd(4 nm)/Cr(t_(Cr))/FeCo(5 nm)三层膜室温下面内磁电阻效应,本文研究了薄膜的层间耦合和界面效应.研究发现,相对于FeCo薄膜,Gd/FeCo薄膜表现出更为明显的各向异性磁电阻.Cr的插入使得电流垂直于磁场时的磁电阻在低场峰值位置处出现一极小值,且这个极小值随着t_(Cr)的增加变得更加明显.当t_(Cr)=3 nm时,几乎完全表现为负自旋阀磁电阻效应.FeCo层与Cr/Gd形成的不同的自旋散射不对称是产生这一负自旋阀磁电阻效应的主要原因.电流平行于磁场时磁电阻峰值随t_(Cr)的振荡和低温下的磁滞回线证实了低温和室温下层间耦合的存在.As one of the most representative features characterizing the spin valve structure,magnetoresistance is an important method to study the interlayer coupling in multilayers.Considering the induced magnetism of rare earth at room temperature due to the coupling and magnetic proximity effect in the structure of rare earth/magnetic transition metal,an intermediate nonmagnetic metal can be inserted to form the spin valve structure to regulate the interlayer coupling,which expands the scope of applications of rare earth in spintronics.In this work,the interlayer exchange coupling and interfacial effects of Gd(4 nm)/Cr(t_(Cr))/FeCo(5 nm)trilayers with different Cr layer thickness(t_(Cr))are studied by means of in plane magnetoresistance.Compared with FeCo film,Gd/FeCo film obtains more obvious anisotropic magnetoresistance.While the magnetoresistance value obtained for the configuration of I⊥H shows a minimum value at the peak due to the insertion of Cr layer,and this minimum value becomes more pronounced with the increase of t_(Cr).When t_(Cr)=3 nm,the negative spin valve effect almost totally overcomes the anisotropic-magnetoresistance effect.Different spin asymmetries of scattering that are formed in FeCo layer and Cr/Gd layers are mainly responsible for creating the negative spin valve magnetoresistance,in which the resistance becomes smaller near the coercive,while the resistance becomes larger at high field parallel to magnetic moment.The oscillation of magnetoresistance with t_(Cr)at I//H and the hysteresis loops at 5 K further confirm the existence of interlayer coupling both at room temperature and 5 K.

关 键 词：FeCo薄膜 磁电阻 层间耦合 稀土 

分 类 号：TB383.2[一般工业技术—材料科学与工程]