银覆盖层对自旋阀三明治结构巨磁电阻的影响

采用射频磁控溅射方法，制备了NiFe/Cu/CoFe和CoFe/Cu/CoFe/NiO两种不同结构类型的自旋阀.当
使用Ag作为镜面覆盖层时，发现当Ag厚度大约在2.0～2.4 nm时，不同结构的自旋阀样品NiFe/Cu/CoFe和
CoFe/Cu/CoFe/NiO的巨磁电阻（GMR）都有较大幅度的提高.对Ag(tAg nm)/NiFe(6 nm)/Cu(2.2 nm)/CoFe
(4 nm)结构自旋阀，当tAg＝2 nm时，样品的GMR达到3.4 ％；对Ag(tAg nm)/CoFe(4 nm)/Cu(2.2 nm)/
CoFe(4 nm)/NiO(70 nm)结构自旋阀，当tAg＝2.4 nm时，样品的GMR从6.9 ％提高到8.3 ％.应用半经典理
论对银覆盖层的镜面反射作用进行了解释.     

应力对LaAlO3/BaTiO3超晶格结构及性能的影响

采用激光脉冲分子束外延技术,在(100)取向SrTiO3或Nb:SrTiO3单晶基片上成功外延生长不同结构的LaAlO3/BaTiO3超晶格。利用高能电子衍射技术和X射线衍射技术对LaAlO3/BaTiO3超晶格的生长过程和微结构进行了表征。发现由于LaAlO3和BaTiO3晶格常数的不匹配,在LaAlO3/BaTiO3超晶格中存在应变,该应变又对超晶格的铁电性能具有很大的影响。而不同的结构存在的应变不同,非对称结构的LaAlO3/BaTiO3超晶格的应变随每个周期中LaAlO3层厚度的增加、BaTiO3层厚度的减少而增大,其剩余极化强度不仅未减少,反而增加。     

XPS Studies of Magnetic Multilayers

NiOx/N81Fe19 and Co/AlOx/Co magnetic multilayers were fabricated by reactive RF/DC magnetron sputtering on clean glass substrates and oxidized Si (100) substrates, respectively. The exchange biasing field (Hex) between NiOx, and Ni81Fe19 as a function of NiOx, oxidation states was studied by X-ray photoelectron spectroscopy (XPS). The oxidation states and the oxide thickness of Al layers in magnetic multilayer films consisting of Co/AlOx/Co were also analyzed. It is found that the Hex of NiOx/Ni81Fe19 films only depends on Ni2+ but not on Ni3+ or Ni. The bottom Co can be completely covered by depositing an Al layer thicker than 2.0 nm. The oxide layer was Al2O3, and its thickness was 1.15 nm.     

复合双压电层FBAR的建模与仿真

在复合单压电层薄膜体声波谐振器(FBAR)的基础上,提出了一种新型的复合双压电层FBAR,它可以大大提高压电材料选择的灵活性。通过建模得到该结构的输入阻抗解析表达式,据此进行了仿真分析。仿真结果表明,基模谐振频率随双压电层结构中的较高声速压电膜的厚度所占比率的增加而加速增大,而相对带宽随较高机电耦合系数的压电膜的厚度与较低机电耦合系数的压电膜的厚度比的增加逐渐增加,并且复合双压电层FBAR出现了单压电层时所没有的模式。     

Microstructures of NiFe/nonmagnetic metal spacer/FeMn films and their influences on exchange coupling

The discovery of the oscillatory exchange coupling between ferromagnetic (FM) layers separated by a nonmagnetic spacer layer in 1986[1] aroused peoples interest in the magnetic prop-erties of metallic multilayered films. FM/ nonmagnetic metal spacer /FM systems with any of the 3d transition metals Fe, Co and Ni or their alloys as FM material have been systematically stud-ied[24]. Oscillatory exchange coupling via spacers has been known as a general phenomenon relevant to many spacer materi…     

NiCo/Cu多层膜的巨磁电阻与磁光克尔效应

本文对用射频磁控溅射方法制备的NiCo／Cu多层膜的层间耦合与磁光克尔效应的内在关联性进行了研究。发现巨磁电阻比与磁光克尔角的幅值1/2随Cu层厚度作同步振荡。其磁光振荡可主要归结于层间耦合引起的铁磁层中电子的光和磁光跃迁的变化。     

石英晶体谐振器探测沉积膜层的特性

本文介绍压电石英晶体谐振器探测沉积膜厚度及速率的工作原理。根据石英晶体和沉积膜层的切变弹性声阻抗理论,并利用在界面处的输入阻抗概念,导出了沉积一种材料膜层时复合系统的谐振频率变化与沉积层材料声阻抗和质量之间的理论关系式,进而导出了沉积多种材料膜层系时的理论关系式。这些关系式是使用石英谐振器精确探测沉积膜层的科学依据。     

Microstructures and magnetic properties of [SiO2/FePt]5/Ag thin films

[SiO2/FePt]5/Ag thin films were deposited by RF magnetron sputtering on the glass substrates and post annealing at 550 ℃ for 30 min in vacuum. Vibrating sample magnetometer and X-ray diffraction analyser were applied to study the magnetic properties and microstructures of the films. The results show that without Ag underlayer [SiO2/FePt]5 films deposited onto the glass are FCC disordered; with the addition of Ag underlayer [SiO]FePt]5/Ag films are changed into L10 and （111） mixed texture. The variation of the SiO2 nonmagnetic layer thickness in [SiO2/FePt]5/Ag films indicates that SiO2-doping plays an important role in improving the order parameter and the perpendicular magnetic anisotropy, and reducing the grain size and intergrain interactions. By controlling SiO2 thickness the highly perpendicular magnetic anisotropy can be obtained in the [SiO2 （0.6 nm）/FePt （3 nm）]5/Ag （50 nm） films and highly （001）-oriented films can be obtained in the [SiO2 （2 nm）/FePt （3 nm）]5/Ag （50 nm） films.     

Effect of silver growth temperature on the contacts between Ag and ZnO thin films

Highly c-axis oriented ZnO thin films were deposited on Si substrates by the pulsed laser deposition (PLD) method. At different growth temperatures, 200 nm silver films as the contact metal were deposited on the ZnO thin films. The growth temperatures have great influence on the crystal quality of Ag films. Current-voltage characteristics were measured at room temperature. The Schottky contacts between Ag and ZnO thin films were successfully obtained when silver electrodes were deposited at 150°C and 200°C. Ohmic contacts were formed while the growth temperatures were lower than 150°C or higher than 200°C. After analysis, the forming of Ag/ZnO Schottky contacts was shown to be dependent on the appearance of the p-type inversion layer at the interface between Ag and ZnO layers.     

Structures and properties of [CoPt/Ag]_n multilayer films

In recent years there has been considerable interest in atomically ordered L10-CoPtfilms as potential materials for ultrahigh density magnetic recording (UDMR) media[1].The L10 phase CoPt alloy has high anisotropy constant of 107—108 erg/cm3, which is ofcrucial importance for UDMR media with a small grain size below 10 nm, because highmagnetocrystalline anisotropy is needed to create a barrier to thermally activatedswitching of the magnetization[2, . The as-deposited CoPt film with equi…     

电化学牺牲双阳极法一步制备铁/铝水滑石纳米片

传统合成铁/铝水滑石纳米片(Fe/Al-LDHs)方法往往需要使用不稳定的铁盐,还要在一定温度下进行长时间的老化。为了克服这些缺点,开发了一种易于操作、环境友好且可以规模化操作的电化学牺牲阳极水滑石制备方法。采用牺牲阳极法成功地合成了六边形Fe/Al-LDHs,厚度约为32 nm,直径为50～100 nm,金属摩尔比[Fe]/[Al]=2∶1。实验表明:Fe/Al-LDHs的结晶过程主要依赖于最先沉淀的Al(OH)_3形成的晶核和Fe的化学价;在低电流密度下,同时采用Fe和Al为牺牲阳极,通过控制输出电流来控制阳极电解的金属量,可快速大规模制备Fe/Al-LDHs,具有良好的应用前景。     

Effects of Lay-up Types of Out-of-autoclave Prepregs on Preparation Quality of L-shape Composite Laminates

Effects of layer quantities and stacking sequences on L-shape composite manufacturing qualities in using OOA(out-of-autoclave) prepregs were studied.The mechanisms of air evacuated in 5 kinds of lay-ups were revealed by image analysis of cut surfaces and thickness measurements.Results show that air in OOA prepregs is evacuated in two ways.Most of the air is forced out of layers directly by vacuum before air accesses in prepregs closed.Very little entrapped air moves perpendicularly to outer layers under hydrostatic resin pressure.When a laminate contains less than 16 layers,voids can hardly be found in layers.When a laminate contains more than 16 layers,voids cannot be expelled completely during the window of vertical movement.As for stacking sequences,the synergetic effect of slip function and nest function determines the thickness and voids content of laminates.Results show that the average of single layer thickness of unidirectional layers is the lowest,and the average of single layer thickness of quasi-isotropic layers is the highest.The voids content of quasi isotropic is the highest,which is consistent with the theoretical analysis.     

680℃蒸汽下T91钢的氧化行为

采用热分析天平连续称重法对T91钢680℃水蒸气氧化动力学进行研究,用扫描电镜、X射线能谱仪和X—Ray物相分析仪对腐蚀产物的形貌、成分、物相等进行测定。结果表明：T91钢在氧化45h后,其动力学曲线服从直线规律,氧化速率为0．189g·m^-2·h^-1;氧化膜呈现明显三层结构,内层为致密富Cr的CrFe2O4无晶界层,中层存在大量柱状空洞贫Cr的以Fe3O4为主、CrFe2O4少量的尖晶石层,外层为Fe2O3无Cr的等轴状晶组织。     

Structural and optical characteristics of Al_xGa_(1-x)N/AlN superlattice

AlN/Al0.3Ga0.7N superlattices were grown on (0001) sapphire substrate by metal-organic chemical vapor deposition (MOCVD). The superlattice period varies from 6 to 30. The layer thickness of different period stack was designed. GaN or AlGaN template was employed for growing AlN/AlGaN superlattices. Reflectivity, SEM, AFM and XRD data of the AlxGa1-xN/AlN superlattices are presented. It is found that the templates used have an intensive impact on surface roughness and interfacial properties of following AlN/AlGaN superlattices. The result of atomic force microscopy indicates that AlN/AlGaN superlattices grown on GaN template exhibit quasi-two-dimensional growth mode. The resulting superlattice has a smooth surface morphology and distinct interface. No crack is observed in the area of a 2-inch wafer.     

Microstructure of Ni / WC surface composite layer on gray iron substrate

The surface infiltrated composite (Ni/WC) layers on gray iron substrate were fabricated through a vacuum infiltration casting technique (VICT) using Ni-based composite powder with different WC particles content as raw materials.The microstructures of surface infiltrated composite layer,the interface structures between surface composite layer and the substrate,the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated.The infiltrated composite layer includes a surface composite layer and a transition layer,and the thickness of the transition layer decreases with the increasing content of WC.The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μm which was the thickest for all transition layers with different WC content.The surface composite layer was mainly composed of WC,W2C,FeB and NiB,along with Ni-Cr-Fe,Ni (Cr) solid solution,Ni (Si) solid solution and Ni (Fe) solid solution.The transition layer was composed of Ni (Cr) solid solution,Ni (Fe) solid solution,Ni (Si) solid solution,Fe (Ni) solid solution and eutectic.The surface macro-hardness and micro-hardness of the infiltrated layer had been evaluated.The macro-hardness of the surface composite layer decreases with the WC content increasing,and the average macro-hardness is HRC60.The distribution of micro-hardness presents gradient change.The average micro-hardness of the infiltrated layer is about HV1000.     

Organic Light Emitting Diodes with p-Si Anodes and Semitransparent Ce/Au Cathodes

The Ce (x nm)/Au (15 nm) stacked layers were used as semitransparent cathodes in the top-emission organic light emitting devices (TOLEDs) fabricated on a p-type silicon anodes and substrate,where x varies from 4 to 16.The consequence of the Ce layer thickness on transmittance and the device performance were studied when the organic layers NPB (60 nm)/ALQ (60 nm) were kept unchanged,where NPB was N,N'-bis-(1-naphthl)-diphenyl-1,1'-biphenyl-4,4'-diamine,and AlQ is tris-(8-hydroxyquinoline) aluminum.The cathod...     

GF/UP体系界面上偶联剂结构层与体系微观流变学的研究

以有机硅烷、钛酸酯两种偶联剂用不同方法处理玻璃纤维后,利用XRF法测定了纤维表面的偶联剂含量及厚度。研究了由上述纤维与不饱和聚酯(UP)组成的分散体系的流变特性。结果表明,玻璃表面所吸附的硅烷偶联剂内层刚性比外层要大;而玻璃表面吸附的钛酸酯偶联剂各层次对体系流变特性的影响基本相同,反映出玻璃表面的钛酸酯内外层具有相近的柔性结构。     

考虑层间接触的旧水泥混凝土路面 加铺厚沥青层的力学分析

基于试验路段省道120线的路面技术状况,利用有限元软件ABAQUS建立旧水泥路面加铺厚沥青层的三维力学分析模型,并考虑了旧路面与加铺层的层间接触和旧路面间接缝.首先计算分析了结构的温度场,然后分析了结构在温度荷载和车辆荷载耦合作用下调平层厚度对结构力学响应的影响及各结构层的功能需求.得出以下结论：在典型高温天气下,面层顶部的温度高于55℃;温度场变化幅度较大的范围在0~30 cm,增加加铺层厚度可降低因旧路面结构引起的温度应力;加铺层承受了较大的竖向变形,上面层和调平层承受较大的拉应力,是路面由上而下开裂和由下向上疲劳开裂的主要原因;上面层承受着较大的压应力和剪应力,同时下面层和调平层也承受了较大的剪应力;增加调平层厚度,可有效降低调平层的拉应力、压应力和剪应力,可以较大降低对旧路面结构的抗拉强度要求,从而增强了结构抗反射裂缝能力和抗疲劳能力;根据力学分析,给出了各加铺层混合料设计建议.研究成果为改善道路材料设计和提高加铺结构耐久性提供力学理论依据.     

Surface Organic Modification of Fe3O4 Magnetic Nanoparticles

The surface organic modification of Fe3O4 nanoparticles with silane coupling reagent KH570 was studied.The modified and unmodified nanoparticles were characterized by FT-IR,XPS and TEM.The spectra of FT-IR and XPS revealed that KH570 was coated onto the surface of Fe3O4 nanoparticles to get Fe-O-Si bond and an organic coating layer also was formed.Fe3O4 nanoparticles were spheres partly with mean size of 18.8 nm studied by TEM,which was consistent with the result 17.9 nm calculated by Scherrer'S equation.KH570 was adsorbed on surface and formed chemistry bond to be steric hindrance repulsion which prevented nanoparticles from reuniting.Then glycol-based Fe3O4 magnetic liquids dispersed stably was gained.     

直流磁过滤电弧源制备银膜的工艺参数研究

为了探索电弧离子镀技术制备银薄膜中相关的工艺参数,利用直流磁过滤电弧源在K9玻璃和硅片上制备了银膜,通过白光干涉仪和剥离实验对所制备银膜的厚度、表面粗糙度和附着力进行检测,分析靶电流、基片偏压和过渡层对银薄膜沉积速率、粗糙度及附着力等特性的影响．实验结果表明：当靶电流为90．0A时,沉积速率为1．84nm／s,在偏压为＋10V时,得到膜层粗糙度为0．5355nm;利用过渡层的辅助,通过电弧离子镀有效地提高了银膜的附着力．