自旋轨道矩调控的垂直磁各向异性四态存储器结构  

Demonstration of four-state memory structure with perpendicular magnetic anisotropy by spin-orbit torque

作　　者：盛宇 张楠 王开友[2,3,4] 马星桥 Sheng Yu;Zhang Nan;Wang Kai-You;Ma Xing-Qiao(School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China;State Key Laboratory of Superlattiees and Microstruetures, Institute of Semiconductors, Chinese Academy of Sciences Beijing 100083, China;College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China） （4Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]北京科技大学数理学院,北京100083 [2]中国科学院半导体研究所半导体超晶格国家重点实验室,北京100083 [3]中国科学院大学材料科学与光电技术学院,北京100049 [4]中国科学院拓扑量子计算卓越创新中心,北京100049

出　　处：《物理学报》2018年第11期206-211,共6页Acta Physica Sinica

基　　金：国家科技支撑计划(批准号:2017YFA0303400);国家自然科学基金(批准号:11174030;11474272;61774144);中国科学院基金(批准号:QYZDY-SSW-JSC020;XDPB0603);香港王宽诚教育基金资助的课题~~

摘　　要：利用氧化钽缓冲层对垂直各向异性钴铂多层膜磁性的影响,构想并验证了一种四态存储器单元.存储器器件包含两个区域,其中一区域的钴铂多层膜[Pt(3 nm)/Co(0.47 nm)/Pt(1.5 nm)]直接生长在热氧化硅衬底上,另一个区域在磁性膜和衬底之间沉积了一层氧化钽作为缓冲层[TaO x(0.3 nm)/Pt(3 nm)/Co(0.47 nm)/Pt(1.5 nm)],缓冲层导致两个区域的垂直磁各向异性不同.在固定的水平磁场下对器件施加与磁场同向的电流,由于电流引起的自旋轨道耦合力矩,两个区域的磁化取向均会发生翻转,且拥有不同的临界翻转电流.改变通过器件导电通道的电流脉冲形式,器件的磁化状态可以在4个态之间切换.本文器件的结构为设计自旋轨道矩存储器件提供了新的思路.Current, instead of magnetic field, induced magnetization switching is very important for future spintronics in information storage or/and information processing. As one of the effective current-induced magnetization methods, spin-orbit torque （SOT） has aroused considerable interest because it has low-power consumption and can improve the device endurance. Normal metal （NM）/ferromagnetic metal （FM） are the common materials used for SOTs, where the NM denotes the materials with strong spin-orbit coupling such as Pt, Ta, W, etc. Owing to the spin Hall effect, the in-plane current in NM layer can be converted into a vertical spin current that exerts torques on the adjacent FM layers. Spin current can also come from the NM/FM interface charge-spin conversion due to interfacial asymmetry, exerting torques on the adjacent FM layers. Materials with in-plane and perpendicular magnetic anisotropy are used to study the SOT-induced magnetization switching. Compared with the memories using the in-plane ferromagnetic films, the magnetic memories using NM/FM multilayers with perpendicular magnetic anisotropy can have much high integration density. Currently the used information storage was based on the two-state memory cell. Owing to more than two states contained in one memory cell, multiple states memory manipulated by electric current could further benefit the higher-density memory. In this paper, a four-state memory unit is demonstrated by the influence of TaOx buffer layer on the magnetic anisotropy of Pt/Co/Pt multilayers. The memory unit consists of two regions. One is directly deposited on thermal oxide Si substrate [Pt（3 nm）/Co（0.47 nm）/Pt（1.5 nm）] and the other has a buffer layer of WaOx [TaOx（0.3 nm）/Pt（3 nm）/ Co（0.47 nm）/Pt（1.5 nm）], thus leading to the difference in magnetic property between these two regions. According to the Z axis magnetic hysteresis loops of two regions, measured by polar magneto-optical Kerr effect, the coercivity of the region with TaOx is obtained to

关 键 词：自旋电子学 自旋轨道耦合矩 四态存储器 

分 类 号：O469[理学—凝聚态物理] TP333[理学—电子物理学]