Effects of Fe-Oxide and Mg Layer Insertion on Tunneling Magnetoresistance Properties of CoFeB/MgO/CoFeB Magnetic Tunnel Junctions  

作　　者：娄永乐 张玉明 郭辉 徐大庆 张义门 

机构地区：[1]School of Microelectronics,Xidian University [2]School of Electrical and Control Engineering,Xi'an University of Science and Technology

出　　处：《Chinese Physics Letters》2016年第11期124-126,共3页中国物理快报（英文版）

基　　金：Supported by the National Defense Advance Research Foundation under Grant No 9140A08XXXXXX0DZ106;the Basic Research Program of Ministry of Education of China under Grant No JY10000925005;the Scientific Research Program Funded by Shaanxi Provincial Education Department under Grant No 11JK0912;the Scientific Research Foundation of Xi'an University of Science and Technology under Grant No 2010011;the Doctoral Research Startup Fund of Xi'an University of Science and Technology under Grant No 2010QDJ029

摘　　要：To study the influence of CoFeB/MgO interface on tunneling magnetoresistance （TMR）, different structures of magnetic tunnel junctions （MTJs） are successfully prepared by the magnetron sputtering technique and characterized by atomic force microscopy, a physical property measurement system, x-ray photoelectron spectroscopy, and transmission electron microscopy. The experimental results show that TMR of the CoFeB/Mg/MgO/CoFeB structure is evidently improved in comparison with the CoFeB/MgO/CoFeB structure because the inserted Mg layer prevents Fe-oxide formation at the CoFeB/MgO interface, which occurs in CoFeB/MgO/CoFeB MTJs. The inherent properties of the CoFeB/MgO/CoFeB, CoFeB/Fe-oxide/MgO/CoFeB and CoFeB/Mg/MgO/CoFeB MTJs are simulated by using the theories of density functions and non-equilibrium Green functions. The simulated results demonstrate that TMR of CoFeB/Fe-oxide/MgO/CoFeB MTJs is severely decreased and is only half the value of the CoFeB/Mg/MgO/CoFeB MTJs. Based on the experimental results and theoretical analysis, it is believed that in CoFeB/MgO/CoFeB MTJs, the interface oxidation of the CoFeB layer is the main reason to cause a remarkable reduction of TMR, and the inserted Mg layer may play an important role in protecting Fe atoms from oxidation, and then increasing TMR.To study the influence of CoFeB/MgO interface on tunneling magnetoresistance （TMR）, different structures of magnetic tunnel junctions （MTJs） are successfully prepared by the magnetron sputtering technique and characterized by atomic force microscopy, a physical property measurement system, x-ray photoelectron spectroscopy, and transmission electron microscopy. The experimental results show that TMR of the CoFeB/Mg/MgO/CoFeB structure is evidently improved in comparison with the CoFeB/MgO/CoFeB structure because the inserted Mg layer prevents Fe-oxide formation at the CoFeB/MgO interface, which occurs in CoFeB/MgO/CoFeB MTJs. The inherent properties of the CoFeB/MgO/CoFeB, CoFeB/Fe-oxide/MgO/CoFeB and CoFeB/Mg/MgO/CoFeB MTJs are simulated by using the theories of density functions and non-equilibrium Green functions. The simulated results demonstrate that TMR of CoFeB/Fe-oxide/MgO/CoFeB MTJs is severely decreased and is only half the value of the CoFeB/Mg/MgO/CoFeB MTJs. Based on the experimental results and theoretical analysis, it is believed that in CoFeB/MgO/CoFeB MTJs, the interface oxidation of the CoFeB layer is the main reason to cause a remarkable reduction of TMR, and the inserted Mg layer may play an important role in protecting Fe atoms from oxidation, and then increasing TMR.

关 键 词：MGO of TMR FE Effects of Fe-Oxide and Mg Layer Insertion on Tunneling Magnetoresistance Properties of CoFeB/MgO/CoFeB Magnetic Tunnel Junctions in is that on 

分 类 号：O482.5[理学—固体物理]