Bi置换石榴石溅射薄膜读写性能的研究

用ｒｆ溅射方法在玻璃衬底上制备了Ｂｉ置换ＤｙＩＧ薄膜。研究了λ＝５１０ｎｍ时在膜布蒸镀Ｃｒ层后磁光膜的干涉作用为。获得最佳载噪比，给出两层膜结构盘片的最佳设计和最佳读出激光功率。     

磁致伸缩铺层阻尼板壳结构的振动分析

通过理论分析讨论了含磁致伸缩材料和黏弹性材料铺层的层合板壳结构的频率和损失因子。假设黏弹性层仅发生剪切变形, 对磁致伸缩层应用偏置磁场下的线性本构, 推导得到由磁致伸缩层、黏弹性层、复合材料基本层组成的约束阻尼薄壳结构的运动方程, 并求得结构振动频率和损失因子的解。对板、曲板等算例的计算结果表明, 用磁致伸缩材料作约束层可使层合结构损失因子提高。      

激光表面再铸层结构对DZ22定向凝固合金疲劳性能的影响

用扫描电镜观察了以ＤＺ２２定向凝固合金为基材的三种激光打孔工艺形成的激光表面再铸层结构，并在室温和高温（７２０℃）下进行了三类激光孔试件的疲劳试验，分析了激光打孔工艺与再铸层结构的相互联系及对疲劳性能的影响，阐明疲劳裂纹从再铸层形成及扩展过程。     

激光表面再铸层结构对DZ22定向凝固合金疲劳性能的影响

用扫描电镜观察了以ＤＺ２２定向凝固合金为基材的三种激光打孔工艺形成的激光表面再铸层结构，并在室温和高温（７２０℃）下进行了三类激光孔试件的疲劳试验，分析了激光打孔工艺与再铸层结构的相互联系及对疲劳性能的影响，阐明疲劳裂纹从再铸层形成及扩展过程。     

聚焦光斑磁光极克尔磁滞回线的热效应分析

实验设计并组建了一套磁光极克尔磁滞回线测量装置,该装置可以通过改变照射到样品上的激光功率来改变薄膜样品上被聚焦光斑照射的测试点的温度。同时通过计算模拟了激光照射在TbFeCo磁光薄膜上的温度分布情况,得到了薄膜的矫顽力随照射激光功率的变化关系,由此可以确定薄膜的居里温度和补偿温度。为研究磁光薄膜样品在各种温度条件下,磁光性能的变化以及多层磁光薄膜的磁耦合效应提供了有效的手段。     

弯曲型三明治结构FeCuNbCrSiB/Cu/FeCuNbCrSiB多层膜巨磁阻抗效应研究

利用磁控溅射方法及微细加工技术制备了弯曲型三明治结构的FeCuNbCrSiB／Cu／FeCuNbCrSiB多层膜，在频率1～40MHz下研究了多层膜的纵向和横向巨磁阻抗效应，结果表明弯曲型三明治结构多层膜的巨磁阻抗效应高于它的传统的多层膜。在频率10MHz、磁场11．94kA／m下巨磁阻抗效应达-50%。     

超磁致伸缩薄膜研究进展

综述了近几年国内外超磁致伸缩单层膜、多层膜的研究进展;介绍了超磁致伸缩薄膜的制备方法与性能表征;论述了TbDyFe单层薄膜的磁致伸缩和磁学性能以及其成分、应力、热处理、衬底温度等性能的影响因素;详述了超磁致伸缩多层膜组成和结构类型;讨论了热处理、磁场诱导和单层膜厚对多层膜在低场下磁致伸缩和磁学性能的影响,评述和展望了超磁致伸缩薄膜的国内外研发应用现状和发展趋势.     

应用于铯喷泉钟的磁屏蔽系统的设计

高质量磁屏蔽系统是铯喷泉钟的重要部件之一。首先给出评定磁屏蔽效果的3个指标,即磁场均匀区长度、磁场均匀区起点位置和磁屏蔽效率。在此基础上,讨论了利用有限元计算3层磁屏蔽系统的层间径向间距、轴向间距、端盖孔套管长度和端盖连接方式对磁屏蔽的影响,给出了相应的优化参数,并对比了按优化参数设计的3层磁屏蔽与原有4层磁屏蔽系统用有限元计算的磁屏蔽效果。有限元计算结果为中国计量科学研究院新铯喷泉钟磁屏蔽系统的技术设计提供了理论指导。     

双光子多层荧光存储中的变焦选层技术

为了在双光子多层荧光数据存储中实现对信息层的跟踪聚焦,基于目前的光盘存储系统和双元透镜控制方案,提出了一种变焦选层技术。两个可独立控制的音圈电机负责调节两物镜的相对位置。利用聚焦模块提取出的聚焦误差信号,读写系统控制两个电机协调动作改变焦点位置,使得读写焦点在对选定层读写过程中跟踪盘片抖动。选层操作可通过控制一个音圈电机完成。因此,读写系统能实现简单盘片结构条件下的多层荧光数据存储,同时聚焦模块可使系统与现有CD/DVD盘片兼容。利用二维精密平移台和三洋光头(SF-HD60S)中的音圈电机和物镜进行了双光子三维信息读写实验,在材料中存储了三层数据,点间距4μm,层间距20μm。     

几种难熔过渡金属的激光氮化

多脉冲激光辐射使置于氮气氛中的难熔过渡金属钛、钼和表面氮化，形成和组织致密的氮化层，用多种方法分析和表征了氮化层的化学成分和组织结构，激光的作用使得金属表面熔化和氮气激活，导致液相氮化反应，激光引起的加热熔化和激波效应同时使表层组织致密。     

Cellulose‐Based Microparticles for Magnetically Controlled Optical Modulation and Sensing

Responsive materials with birefringent optical properties have been exploited for the manipulation of light in several modern electronic devices. While electrical fields are often utilized to achieve optical modulation, magnetic stimuli may offer an enticing complementary approach for controlling and manipulating light remotely. Here, the synthesis and characterization of magnetically responsive birefringent microparticles with unusual magneto‐optical properties are reported. These functional microparticles are prepared via a microfluidic emulsification process, in which water‐based droplets are generated in a flow‐focusing device and stretched into anisotropic shapes before conversion into particles via photopolymerization. Birefringence properties are achieved by aligning cellulose nanocrystals within the microparticles during droplet stretching, whereas magnetic responsiveness results from the addition of superparamagnetic nanoparticles to the initial droplet template. When suspended in a fluid, the microparticles can be controllably manipulated via an external magnetic field to result in unique magneto‐optical coupling effects. Using a remotely actuated magnetic field coupled to a polarized optical microscope, these microparticles can be employed to convert magnetic into optical signals or to estimate the viscosity of the suspending fluid through magnetically driven microrheology.     

稀土铁石榴石磁光材料及其应用

本文综述了稀土铁石榴石磁光材料及磁光器件研究的最新进展；对最具应用价值的高掺Ｂｉ系列和掺Ｃｅ系列石榴石磁光材料作了介绍；在磁光器件方面选择了最具代表性的磁光隔离器和光纤电流／磁场测试仪加以讨论     

Detection of Defect‐Induced Magnetism in Low‐Dimensional ZnO Structures by Magnetophotocurrent

The detection of defect‐induced magnetic order in single low‐dimensional oxide structures is in general difficult because of the relatively small yield of magnetically ordered regions. In this work, the effect of an external magnetic field on the transient photocurrent measured after light irradiation on different ZnO samples at room temperature is studied. It has been found that a magnetic field produces a change in the relaxation rate of the transient photocurrent only in magnetically ordered ZnO samples. This rate can decrease or increase with field, depending on whether the magnetically ordered region is in the bulk or only at the surface of the ZnO sample. The phenomenon reported here is of importance for the development of magneto‐optical low‐dimensional oxides devices and provides a new guideline for the detection of magnetic order in low‐dimensional magnetic semiconductors.     

超高密度磁存储的展望

磁性存储是最常用的海量存储技术,其记录密度越来越高,发展也越来越快。本文通过对信息记录、读出和存储三个过程的分析,对比了硬磁盘记录、垂直磁记录和磁光记录的优缺点,指出了采用垂直记录模式、非晶结构合金薄膜或铁氧体薄膜介质是实现超高密记录的方向,光辅助磁记录是很有希望的记录技术。同时,还指出量子磁盘技术是未来高密记录的方向。     

磁光盘记录光场畸变分析

运用光波衍射理论，针对磁光盘建立了记录光场的数学模型。该数学模型可全面描述基片杂质大小、位置、透射率对记录光场的影响。利用该数学模型可进一步研究基片杂质与磁畴特性，以及盘片误码的关系。     

Magneto immunoassays for Plasmodium falciparum histidine-rich protein 2 related to malaria based on magnetic nanoparticles

Magneto immunoassay-based strategies for the detection of Plasmodium falciparum histidine-rich protein 2 (HRP2) related to malaria are described for the first time by using magnetic micro- and nanoparticles. The covalent immobilization of a commercial monoclonal antibody toward the HRP2 protein in magnetic beads and nanoparticles was evaluated and compared. The immunological reaction for the protein HRP2 was successfully performed in a sandwich assay on magnetic micro- and nanoparticles by using a second monoclonal antibody labeled with the enzyme, horseradish peroxidase (HRP). Then, the modified magnetic particles were easily captured by a magneto sensor made of graphite-epoxy composite (m-GEC) which was also used as the transducer for the electrochemical detection. The performance of the immunoassay-based strategy with the electrochemical magneto immunosensors was successfully evaluated and compared with a novel magneto-ELISA based on optical detection using spiked serum samples. Improved sensitivity was obtained when using 300 nm magnetic nanoparticles in both cases. The electrochemical magneto immunosensor coupled with magnetic nanoparticles have shown better analytical performance in terms of limit of detection (0.36 ng mL(-1)), which is much lower than the LOD reported by other methods. Moreover, at a low level of HRP2 concentration of 31.0 ng mL(-1), a signal of 15.30 μA was reached with a cutoff value of 0.34 μA, giving a clear positive result with a non-specific adsorption ratio of 51. Due to the high sensitivity, this novel strategy offers great promise for rapid, simple, cost-effective, and on-site detection of falciparum malaria disease in patients, but also to screen out at-risk blood samples for prevention of transfusion-transmitted malaria.     

Influence of particle size on spin switching properties and magnetoelectric coupling in SmFeO<Subscript>3</Subscript>

Controlling the magnetic properties of a material is of great importance for spintronics and magnetoelastic devices. We studied effect of reduced particle size on structural, dielectric and magnetic properties of SmFeO₃ nanoparticles prepared by co-precipitation method (SFO-C) and by combustion (SFO-S). Reduced particle size modified interesting magnetic features of SmFeO₃. Temperature dependent magnetic study reveal significant enhancement in magnetization reversal temperature and drop in spin reorientation transition temperature. The signature of spin reorientation transition for SFO-C (~?300 nm) is marked at ~?450 K, while this temperature drops down to ~?400 K for SFO-C (~?50 nm). The magnetization reversal temperature is achieved at 30.5 K for SFO-C, much higher than 4 K, reported for the single crystal and bulk SmFeO₃. The presence significant anomalies in the temperature dependent dielectric behavior of SmFeO₃ samples across spin reorientation transition temperature indicate magneto electrical coupling. Strong exchange–bias effect is observed at low temperature for both the samples. The lowering of spin reorientation/switching transition temperature due to reduction in particle size and the signature of magnetoelectric coupling at this temperature are useful for room temperature devices. The observed experimental results establish that the spin switching properties of SmFeO₃ can be modified for practical applications in devices.     

Optical methods of the head positioning in magnetic disk systems

This paper reports a new method of head positioning by applying optics to magnetic disk systems. To increase the accuracy of head positioning, several methods in which a servo disk is not used have been investigated. Until now these methods were unsuccessful because of interference between the head positioning signal and the data signal, both of which were recorded on the same data surface. In the method explained here, the head can be positioned on the disk by an optically detected positioning signal without disturbing operation of the magnetic disk system. A unique structure for both the disk and head was investigated. Optical patterns depicting position of the data tracks were formed by coloring the anode oxidized surface layer of an aluminum substrate, and by forming a magnetic film over that. Three optical fibers were imbedded in a hole in the central rail of a Winchester-type ferrite head and were used to read the optical pattern. A stable positioning signal was optically detected from the rotating disk. By using the signal to assemble a simple servo loop, the head could be positioned with ±3 μm accuracy. Potential accuracy was found to be ±0.7 μm.     

磁光盘驱动器聚焦与循轨数字伺服系统

分析了磁光盘驱动器聚焦与循轨数字伺服系统各组成部分的原理，并设计和实现了一套基于ＤＳＰ的数字伺服控制系统，仿真和实验结果表明：这种数字伺服系统的设计方案简化了电路设计，系统性能良好，是一种理想的系统实现方式。     

强磁场对Fe-0．12C合金在顺磁居里温度以上先共析铁素体等温转变的影响

利用光学显微镜研究了强磁场对高纯度Fe—0．12C合金在顺磁居里温度以上先共析铁素体等温转变的影响。结果表明：在铁素体呈顺磁性且磁化率很低的顺磁居里温度以上进行等温转变,强磁场能够显著促进Fe-0．12C合金的块状先共析铁素体的转变,增加块状先共析铁素体的转变量。在顺磁居里温度以上,随等温转变温度的降低,块状先共析铁素体晶粒沿磁场方向伸长且呈链状形式排列。这是因为强磁场作用下先共析铁素体在较低温度等温转变时的磁偶极子相互作用增强所致。