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Chemical states of the atoms in magnetic multilayers Ta/NiO_x/Ni_(81)Fe_(19)/Ta and Co/AlO_x/Co

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Chinese science Bulletin 2002年第4期47卷 276-279页

作者： yu guanghua, zhu fengwu & CHAI Chunlindepartment of materials physics, university of science and technology, beijing 100083, china department of materials physics University of Science and Technology Beijing China

Ta/NiOx/Ni81Fe19/Ta and Co/AlOx/Co multilay-ers were prepared by rf reactive and dc magnetron sputter-ing. The exchange coupling field (Hex) and the coercivity (Hc) of NiOx/Ni81Fe19 as a function of the ratio of Ar to O2 during the deposition process were studied. The composition and chemical states at the interface region of NiOx/NiFe were also investigated using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that when the ratio of Ar to O2 is equal to 7 and the argon sputtering pressure is 0.57 Pa, the x value is approximately 1 and the valence of nickel is +2. At this point, NiOx is anti-ferromagnetic NiO and the corresponding Hex is the largest. As the ratio of Ar/O2 deviates from 7, the Hex will decrease due to the presence of magnetic impurities such as Ni+3 or metallic Ni at the interface region of NiOx/NiFe, while the Hc will increase due to the metallic Ni. Al layers in Co/AlOx/Co multilayers were also studied by angle-resolved XPS. Our finding is

关键词： NiOx/NiFe exchange coupling Co/AlOx/Co X-ray pho-toelectron spectroscopy (XPS) chemical states.

SiO_2/Ta interface reaction in magnetic multilayers and its influence on Ta buffer layers

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Chinese science Bulletin 2002年第19期47卷 1601-1603页

作者： yu guanghua, MA Jidong, zhu fengwu & CHAI Chunlindepartment of materials physics, university of science and technology, beijing 100083, china Institute of Semiconductor, Chinese Academy of sciences, beijing 100083, china department of materials physics University of Science and Technology Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China

Ta is often used as a buffer layer in magnetic multilayers. In this study, Ta/Ni81Fe19/Ta multilayers were deposited by magnetron sputtering on sing-crystal Si with a 300-nm-thick SiO2 film. The composition and chemical states at the interface region of SiO2/Ta were studied using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that there is an "intermixing layer" at the SiO2/Ta interface due to a thermody-namically favorable reaction: 15 SiO2+37 Ta = 6 Ta2O5 + 5 Ta5Si3. Therefore, the Ta buffer layer thickness used to induce NiFe (111) texture increases.

关键词： SiO2/Ta interface interface reaction X-ray photoelectron spectroscopy (XPS).

Microstructures and Magnetic Properties of Fe-Zr-B Based Nanocrystalline Alloys

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science Foundation in china 2002年第1期10卷 28-31页

作者： zhu fengwu Zhang yuan(department of materials physics and Chemistry,university of science and technology beijing, beijing 100083)

We have studied the partitioning of B in Fe -14B and of Zr, B, Si, Cu and Au in FeZrB nanocrys-talline soft magnetic alloys by using atom probe field ion microscopy (APFIM) and high resolution electron microscopy (HREM) in atomic or nano-metric scales and’the effect of Si, Cu, andAuaddition on the magnetic properties. For Fe- 14B after annealing, a -Fe particles with diameters of about 50-100 nm formed and they contain high supersaturated B. For Fe - 7Zr-3B -1 Cu amorphous alloy, it was found that Cu atoms formed clusters prior to the crystallization reaction. During the crystallization, Cu-enriched clusters provided nucle-ation sites for a -Fe phase so that the nucleation density of a -Fe phase increased. For Fe - 7Zr -5B- 1Au amorphous alloys, Au clusters were observed during the nucleation and growth stage of primary a -Fe and a -Fe did not form at the sites of Au cluster. Hence Au does not enhance the nucleation density of a -Fe particles. For Fe-7Zr-4Si-2B alloys it was found that Si atoms are

关键词： nanocrystalline soft magnetic properties atom probe

Perpendicular exchange bias of (Pt/Co)_n/FeMn multilayers

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Journal of university of science and technology beijing 2007年第6期14卷 543-546页

作者： Zhonghai Zhai yang liu Jiao Teng Baohe Li guanghua yu fengwu zhu materials science and Engineering School University of Science and Technology Beijing Beijing 100083 China College of science Shenyang Jianzhu University Shenyang 110168 China department of Mathematics and physics Beijing Technology and Business University Beijing 100037 China

（Pt/Co）n/FeMn multilayers with perpendicular anisotropy （PA） were prepared by magnetron sputtering with Pt as the buffer layer and the capping layer. The dependence of perpendicular exchange bias （PEB）, Hex, on the thickness of the FeMn anfiferromagnet （AFM） layer is similar to that of in-plane exchange bias. The value of Hex for the （Pt/Co）3/FeMn multilayer reaches 22.3 kA/m. A thin Pt spacer was inserted between the Co/FeMn interface to enhance PEB. The PEB reaches the largest at 39.8 kA/m when the thickness of the Pt spacer is 0.4 nm.

关键词： exchange bias perpendicular anisotropy texture multilayers

The influence of the nonmagnetic metal spacer Bi,Ag and Cu on the properties of the multilayer films

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Chinese science Bulletin 2006年第18期51卷 2183-2188页

作者： LI Minghua yu guanghua zhu fengwu LAI Wuyan College of Mechanical Engineering. South china university of technology Guangzhou 510640 China department of materials physics University of Science and Technology Beijing Beijing 100083 China Institute of physics Chinese Academy China

Ta/NiFe/Bi(Ag, Cu)/FeMn/Ta and Ta/ NiFeⅠ /FeMn/Bi(Ag, Cu)/NiFeⅡ/Ta films were prepared by magnetic sputtering. The texture of films was examined by X-ray diffraction (XRD). The depend-ence of the Hex1 between NiFeⅠ/FeMn films and the Hex2 between FeMn/NiFeⅡ on the Bi, Ag and Cu thickness was studied in Ta/NiFeⅠ/FeMn/Bi(Ag, Cu)/ NiFeⅡ/Ta. The experimental results show that the He1 ranged from 130 to 140 Oe with an increase in the nonmagnetic metal spacer thickness. The Hex2 de-creased dramatically and became flat finally with the increase of the Bi, Ag and Cu thickness. XPS results show that Bi, Ag and Cu atoms do not stay entirely at the interface of FeMn/NiFeⅡ film; they are at least partly segregated to the surface of NiFe film. The more Bi, Ag and Cu atoms are deposited, the more they are segregated at the NiFe layer.

关键词： NiFe/FeMn 无磁性垫片交换耦合晶格匹配表面偏析多层膜

Magnetic property and interface structure of Ta/NiO/NiFe/Ta

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Chinese science Bulletin 2001年第5期46卷 438-440页

作者： yu guanghua CHAI Chunlin zhu fengwu XIAO Jimei department of materials physics University of Science and TechnologyBeijing 100083China Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China

Ta/NiO/NiFe/Ta multilayers, utilizing Ta as buffer layer, were prepared by rf reactive and dc magnetron sputtering. The exchange coupling field between NiO and NiFe reached a maximum value of 9.6 ×103 A/m at a NiO film thickness of 50 nm. The composition and chemical states at interface region of Ta/NiO/Ta were studied by using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that there is an 'intermixing layer' at the Ta/NiO (and NiO/Ta) interface due to a thermodynamically favorable reaction 2Ta + 5NiO = 5Ni + Ta2O5. This interface reaction has a great effect on exchange coupling. The thickness of Ni+NiO estimated by XPS depth-profiles is about 8-10 nm.

关键词： NiO interface reaction X-ray photoelectron spectros-copy exchange coupling.

Effect of Cu surface segregation on the exchange coupling field of NiFe/FeMn bilayers

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Chinese science Bulletin 2001年第22期46卷 1934-1936页

作者： LI Minghua yu guanghua zhu fengwu JIANG Hongwei LAI Wuyan department of materials physics Beijing University of Science and TechnologyBeijing 100083China Institute of physics Chinese Academy of SciencesBeijing 100080China

The NiFe/FeMn bilayers with different buffer layers (Ta or Ta/Cu) were prepared by magnetron sputtering. Results show that the exchange coupling field of NiFe/FeMn fllms with Ta buffer is higher than that of the films with Ta/ Cu buffer. We analysed the reasons by investigating the crystallographic texture, surface roughness and surface segregation of both fllms, respectively. We found that the decrease of the exchange coupling fields of NiFe/FeMn fllms with Ta/ Cu buffer layers was mainly caused by the Cu surface segregation on NiFe surface.

关键词： NiFe/FeMn exchange coupling field texture surface roughness surface segregation.

MOF-Like 3D Graphene-Based Catalytic Membrane Fabricated by One-Step Laser Scribing for Robust Water Purification and Green Energy Production

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Nano-Micro Letters 2022年第11期14卷 48-61页

作者： Xinyu Huang Liheng Li Shuaifei Zhao Lei Tong Zheng Li zhuiri Peng Runfeng Lin Li Zhou Chang Peng Kan-Hao Xue Lijuan Chen Gary J.Cheng zhu Xiong Lei Ye School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074People’s Republic of China Hubei yangtze Memory Laboratories Wuhan 430205People’s Republic of China Institute for Frontier materials Deakin UniversityGeelongVIC 3216Australia Key Laboratory of New Processing technology for Nonferrous Metal and materials(Ministry of Education) Guangxi Key Laboratory of Optical and Electronic Materials and DevicesCollege of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004People’s Republic of China College of Chemistry and materials science Hunan Agricultural UniversityHunan 410128People’s Republic of China School of Material science and Engineering Hunan University of Science and TechnologyXiangtanHunan ProvincePeople’s Republic of China School of Industrial Engineering and Birck Nanotechnology Centre Purdue UniversityWest LafayetteIN 47907USA Institute of Environmental Research at Greater Bay Key Laboratory for Water Quality and Conservation of the Pearl River DeltaMinistry of EducationGuangzhou UniversityGuangzhou 510006GuangdongPeople’s Republic of China

Increasing both clean water and green energy demands for survival and development are the grand challenges of our ***,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)with active metal nanoparticles(AMNs)loading for simultaneously obtaining the water purification and clean energy generation,via a“green”one-step laser scribing *** as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs,which exhibits high permeated fluxes(over 100 L m^(−2) h^(−1))and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving(0.1 bar).After adsorption saturating,the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis,and restores the adsorption capacity well for the next time membrane *** importantly,the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term ***,the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation,realizing the membrane catalytic hydrolysis reactions for hydrogen energy ***“green”precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well.

关键词： 3D graphene Laser scribing Catalytic membrane Water purification Hydrogen production