Co2FeA10.5Si0.5 （CFAS）-based multilayers sandwiched by MgO layers have been deposited and annealed at different temperatures. Perpendicular magnetic anisotropy （PMA） with the magnetic anisotropy energy density Ku ...Co2FeA10.5Si0.5 （CFAS）-based multilayers sandwiched by MgO layers have been deposited and annealed at different temperatures. Perpendicular magnetic anisotropy （PMA） with the magnetic anisotropy energy density Ku ≈2.5x106 erg/cm3 （1 erg = 10-7 J） and the coercivity He = 363 Oe （10e = 79.9775 A.m-1） has been achieved in the Si/SiO2/MgO （1.5 nm）/CFAS （2.5 nm）/MgO （0.8 nm）/Pt （5 nm） film annealed at 300 ℃. The strong PMA is mainly due to the top MgO layer. The structure can be used as top magnetic electrodes in half-metallic perpendicular magnetic tunnel junctions.展开更多
MgO thin films were deposited on Si（100） substrates by laser ablation under various substrate temperatures （Tsub）,expecting to provide a candidate buffer layer for the textured growth of functional perovskite oxid...MgO thin films were deposited on Si（100） substrates by laser ablation under various substrate temperatures （Tsub）,expecting to provide a candidate buffer layer for the textured growth of functional perovskite oxide films on Si substrates.The effect of Tsub on the preferred orientation,crystallinity and surface morphology of the films was investigated.MgO films in single-phase were obtained at 473-973 K.With increasing Tsub,the preferred orientation of the films changed from （200） to （111）.The crystallinity and surface morphology was different too,depending on Tsub.At Tsub=673 K,the MgO film became uniform and smooth,exhibiting high crystallinity and a dense texture.展开更多
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 char...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.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50831002, 51271020, 50971025, 51071022, and 11174031)the National Basic Research Program of China (Grant No. 2012CB932702)+2 种基金PCSIRT, Beijing Nova Program, China (Grant No. 2011031)the Beijing Municipal Natural Science Foundation, China (Grant No. 2102032)the Fundamental Research Funds for the Central Universities, China
文摘Co2FeA10.5Si0.5 （CFAS）-based multilayers sandwiched by MgO layers have been deposited and annealed at different temperatures. Perpendicular magnetic anisotropy （PMA） with the magnetic anisotropy energy density Ku ≈2.5x106 erg/cm3 （1 erg = 10-7 J） and the coercivity He = 363 Oe （10e = 79.9775 A.m-1） has been achieved in the Si/SiO2/MgO （1.5 nm）/CFAS （2.5 nm）/MgO （0.8 nm）/Pt （5 nm） film annealed at 300 ℃. The strong PMA is mainly due to the top MgO layer. The structure can be used as top magnetic electrodes in half-metallic perpendicular magnetic tunnel junctions.
基金Funded by the International Science and Technology Cooperation Project (No.2009DFB50470)the National Nature Science Foundation of China (No.50802071)International Science and Technology Cooperation Project of Hubei Province (No.2010BFA017)
文摘MgO thin films were deposited on Si（100） substrates by laser ablation under various substrate temperatures （Tsub）,expecting to provide a candidate buffer layer for the textured growth of functional perovskite oxide films on Si substrates.The effect of Tsub on the preferred orientation,crystallinity and surface morphology of the films was investigated.MgO films in single-phase were obtained at 473-973 K.With increasing Tsub,the preferred orientation of the films changed from （200） to （111）.The crystallinity and surface morphology was different too,depending on Tsub.At Tsub=673 K,the MgO film became uniform and smooth,exhibiting high crystallinity and a dense texture.
基金Supported by the National Defense Advance Research Foundation under Grant No 9140A08XXXXXX0DZ106the Basic Research Program of Ministry of Education of China under Grant No JY10000925005+2 种基金the Scientific Research Program Funded by Shaanxi Provincial Education Department under Grant No 11JK0912the Scientific Research Foundation of Xi'an University of Science and Technology under Grant No 2010011the Doctoral Research Startup Fund of Xi'an University of Science and Technology under Grant No 2010QDJ029
文摘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.
