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Preparation of BST nanocrystals embedded in SiO_2 film by magnetron sputtering for nonvolatile memory applications

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Chinese Science Bulletin 2011年第11期56卷 1139-1141页

作者： WANG Li SUN HongFang ZHOU HuiHua ZHU Jing Beijing National center for Electron microscopy Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

We develop a method that uses magnetron sputtering to fabricate barium strontium titanate (BST) nanocrystals embedded in dielectric SiO2 *** electron microscope images show that the BST nanocrystals have an average diameter of 5 nm and are well distributed in the SiO2 *** addition,we also analyze the BST nanocrystals composition deviation during the sputtering process by electron dispersive spectroscopy.

关键词： SiO2薄膜纳米晶体磁控溅射 BST 嵌入式非易失性 Si02 透射电子显微镜

Effect of anneal pre-treatment of polycrystalline aluminum sheets on synthesis of highly-ordered anodic aluminum oxide membranes

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Science China(Technological Sciences) 2008年第11期51卷 1838-1842页

作者： ZHANG Lu ZHANG Xiao PAN CaoFeng ZHU Jing Beijing National center for Electron microscopy Lab of Advanced MaterialsDepartment of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Anodic aluminum oxide (AAO) membranes with large ordered pore domains were successfully prepared by adopting the anneal pre-treatment of polycrystalline alu- minum sheets. A statistical method with Gaussian distribution was introduced to quantitatively study the size of the domain with ordered pores. The largest average area of ordered pore domains was 2.6 μm2±0.11 μm2. The corresponding AAO membrane was synthesized by aluminum sheets annealed at 893 K for 24 h.

关键词： anodic aluminum oxide (AAO) annealing temperature annealing duration Gaussian distribution

Modulation of magnetic and electrical properties of bilayer graphene quantum dots using rotational stacking faults

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Chinese Physics B 2019年第7期28卷 504-510页

作者： Hong-Ping Yang Wen-Juan Yuan Jun Luo Jing Zhu National center for Electron microscopy in Beijing School of Materials Science and Engineering the State Key Laboratory of New Ceramics and Fine Processing Key Laboratory of Advanced Materials(MOE) Tsinghua University Beijing 100084 China center for Electron microscopy Institute for New Energy Materials & Low-Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 China

Bilayer graphene quantum dots with rotational stacking faults(RSFs) having different rotational angles were *** the first-principles calculation, we determined that these stacking faults could quantitatively modulate the magnetism and the distribution of spin and energy levels in the electronic structures of the *** addition, by examining the spatial distribution of unpaired spins and Bader charge analysis, we found that the main source of magnetic moment originated from the edge atoms of the quantum *** research results can potentially provide a new path for producing all-carbon nanodevices with different electrical and magnetic properties.

关键词： bilayer graphene quantum dots rotational stacking faults first-principles calculation

Synthesis and electrical characterization of tungsten oxide nanowires

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Chinese Physics B 2009年第7期18卷 3024-3030页

作者：黄睿朱静于荣 Beijing National center for Electron microscopy The State Key Laboratory of New Ceramics and Fine ProcessingLaboratory of Advanced MaterialsDepartment of Materials Science and EngineeringTsinghua University

Tungsten oxide nanowires of diameters ranging from 7 to 200 nm are prepared on a tungsten rod substrate by using the chemical vapour deposition （CVD） method with vapour-solid （VS） *** powders are used to control oxygen concentration in the furnace,thereby assisting the growth of the tungsten oxide *** grown tungsten oxide nanowires are determined to be of crystalline W18O49. I-V curves are measured by an in situ transmission electron microscope （TEM） to investigate the electrical properties of the *** of the I-V curves observed are symmetric,which reveals that the tungsten oxide nanowires are semiconducting. Quantitative analyses of the experimental I-V curves by using a metal semiconductor-metal （MSM） model give some intrinsic parameters of the tungsten oxide nanowires,such as the carrier concentration,the carrier mobility and the conductivity.

关键词： tungsten oxide nanowires chemical vapour deposition (CVD) electrical characterization metal semiconductor metal (MSM) structure

Glass Formation Ability and Kinetics of the Gd55A120Ni25 Bulk Metallic Glass

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Chinese Physics Letters 2006年第3期23卷 672-674页

作者：赵哲龙夏雷丁鼎董远达 Institute of Materials Shanghai University Shanghai 200072Center for Advanced Microanalysis Shanghai University Shanghai 200444

We report a new bulk glass-forming alloy GdssA12oNi25. The bulk sample of the alloy is prepared in the shape of rods in diameter 2ram by suction casting. The rod exhibits typical amorphous characteristics in the x-ray diffraction pattern, paramagnetic property at 30OK, distinct glass transition and multi-step crystallization behaviour in differential scanning calorimetry traces. The gJass formation ability of the alloy is investigated by using the reduced glass transition temperature Trg and the parameter γ- Kinetics of glass transition and primary crystallization is also studied. The fragility parameter m obtained from the Vogel-Fulcher-Tammann dependence of glass transition temperature Tg on In φ （φ is the heating rate） classifies the bulk metallic glasses into the intermediate category according to Angell＇s classification.

关键词： Glass Formation Ability Kinetics Bulk Metallic Glass

Preparation of three-dimensional graphene foam for high performance supercapacitors

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Progress in Natural Science:Materials International 2017年第2期27卷 177-181页

作者： Yunjie Ping Youning Gong Qiang Fu Chunxu Pan School of Physics and Technology and MOE Key Laboratory of Artificial Micro-and Nano-structuresWuhan University center for Electron microscopy Wuhan University

Supercapacitor is a new type of energy-storage device, and has been attracted widely attentions. As a two dimensional（2D） nanomaterials, graphene is considered to be a promising material of supercapacitor because of its excellent properties involving high electrical conductivity and large surface area. In this paper, the largescale graphene is successfully fabricated via environmental-friendly electrochemical exfoliation of graphite, and then, the three dimensional（3D） graphene foam is prepared by using nickel foam as template and FeCl;/HCl solution as etchant. Compared with the regular 2D graphene paper, the 3D graphene foam electrode shows better electrochemical performance, and exhibits the largest specific capacitance of approximately 128 F/g at the current density of 1 A/g in 6 M KOH electrolyte. It is expected that the 3D graphene foam will have a potential application in the supercapacitors.

关键词： Supercapacitor 3D graphene foam 2D graphene paper Electrochemical performance

Chemical Oxidation of La2CuO4 Epitaxial Thin Films Grown by Pulsed Laser Deposition

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Chinese Physics Letters 2007年第6期24卷 1674-1677页

作者：汪春昌闰允杰朱静 Beijing National center for Electron microscopy Tsinghua University Beijing 100084 Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084

Chemical oxidation is used to induce superconductivity in La2CuO4 expitaxial thin films fabricated by pulsed laser deposition technique. Details about the influence of oxidation time on structural, surface morphology, Raman spectra, and electrical properties have been investigated. The results convince that successful uptake of oxygen occurs in the oxidized films, and the content of the inserted oxygen increases with increasing oxidation interval. The possible mechanism for the excess oxygen insertion into the film is also discussed.

关键词： ELECTROCHEMICAL OXIDATION SPIN FLUCTUATIONS THERMAL-TREATMENT RAMAN-SCATTERING SUPERCONDUCTIVITY TEMPERATURE INDUCTION NACLO EFFUSION

Ni-induced stepwise capacity increase in Ni-poor Li-rich cathode materials for high performance lithium ion batteries

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Nano Research 2015年第3期8卷 808-820页

作者： Delai Ye Chenghua Sun Yu Chen Kiyoshi Ozawa Denisa Hulicova-JurcakovaI Jin Zou Lianzhou Wang Nanomaterials Centre School of Chemical Engineering and Australian Institute of Bioengineering and Nanotechnology The University of Queensland Brisbane QLD 4072 Australia School of Chemistry Monash University Clayton Victoria 3800 Australia National Institute for Materials Science Tsukuba Ibaraki 305-0047 Japan Centre for microscopy and microanalysis and Material Engineering The University of Queensland Brisbane QLD 4072 Australia

Li-rich cathode materials have been considered as promising candidates for high-energy lithium ion batteries （LIBs）. In this study, we report a new series of Li-rich materials （Li[Li1/B-2x/BMn2/3-x/3Nix]O2 （0.09 ≤x≤ 0.2）） doped with small amounts of Ni as cathode materials in LIBs, which exhibited unusual phenomenon of capacity increase up to tens of cycles due to the continuous activation of the Li2MnO3 phase. Both experimental and computational results indicate that unlike commonly studied Ni-doped Li-rich cathode materials, smaller amounts of Ni doping can promote the stepwise Li2MnO3 activation to obtain increased specific capacity and better cycling capability. In contrast, excessive Ni will over-activate the Li2MnO3 and result in a large capacity loss in the first cycle. The Lil.25Mn0.625Ni0.12sO2 material with an optimized content of Ni delivered a superior high capacity of -280 mAh.g-1 and good cycling stability at room temperature.

关键词： Ni-doping capacity-increase Li-rich cathode materials lithium ion battery

Correlation between precipitates evolution and mechanical properties of Al-Sc-Zr alloy with Er additions

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Journal of Materials Science & Technology 2022年第4期99卷 61-72页

作者： Li Liu Jian-Tang Jiang Xiang-Yuan Cui Bo Zhang Liang Zhen Simon P.Ringer School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China China-Ukraine Institute of Welding Guangdong Academy of SciencesGuangzhou 510651China School of Aerospace Mechanical and Mechatronic Engineeringand Australian Centre for Microscopy and MicroanalysisThe University of SydneyNew South Wales 2006Australia School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Correlation between precipitates evolution and mechanical properties of Al-Sc-Zr alloy with Er additions during isothermal ageing were investigated by microhardness measurements,transmission electron microscopy,atom probe tomography and density functional theory-based *** results demonstrate that the Er additions significantly improve the hardness during elevated temperature ageing,especially at 400℃.This is mainly because Er additions increase the nucleation rate of the Al_(3)(Er,Sc,Zr)precipitates,resulting in a higher density of fine and uniform dispersion of L1_(2)structured ***-principles calculations demonstrate that the second nearest neighboring solute-solute interactions for the species Sc,Zr and Er are energetically favored–a key feature to rationalize the observed precipitate structure and the underlying formation *** sequential formation of the core/shell precipitates in the Er-free alloy and core/double-shell precipitates in the Er-containing alloy arises due to the different solute-solute and solute-vacancy interaction energies,and the relative diffusivities of the Er,Sc and Zr species in *** results shed light on the beneficial effects of Er additions on the agehardening behavior of Al-Sc-Zr alloy and provide guidance for designing the ageing treatments for the Al-Sc-Zr(-Er)alloys.

关键词： Al alloys Isothermal ageing Microhardness Transmission electron microscopy Atom probe tomography First-principles calculations