Ag底层对TbFeCo薄膜磁性能的影响

采用射频磁控溅射法在玻璃基片上制备了TbFeCo/Ag非晶垂直磁化膜，研究了Ag底层厚度对TbFeCo薄膜磁性能的影响。原子力显微镜、振动样品磁强计与磁光盘测试仪测量结果表明：薄的银底层具有较高的表面粗糙度可以显著增大TbFeCo薄膜的矫顽力，改善TbFeCo薄膜的磁光温度特性，该薄膜有望用作高密度垂直记录介质与光磁混合记录介质。     

基片及基片温度对Fe4N薄膜的形成及其特性的影响

以双离子束溅射法在（111）硅片和玻璃上分别制得了单－γ′－Fe4N薄膜，研究了基片及基片温度对薄膜的结构和磁性能的影响，结果表明，（111）硅片为基片，可制得无晶粒择优取向的单一γ′－Fe4N相；而以玻璃为基片，在基片温度为160℃时，则可制得具有（100）面晶粒取向的单一γ′－Fe4N相薄膜，与无晶粒择优取向的γ′－Fe4N相比较，具有（100）面晶粒取向的γ′－Fe4N相的矫顽力较低，易达到磁饱和，但二者的饱和磁化强度基本一致。     

基片倾斜角度对TbFe薄膜磁致伸缩性能的影响

采用直流磁控溅射法制备了非晶态 TbFe磁致伸缩薄膜,通过基片的倾斜安装研究了基片倾斜角度对TbFe薄膜磁致伸缩性能的影响。结果表明:随着基片倾斜角度的增大 TbFe薄膜的磁致伸缩系数增大,在外加磁场110kA·m-1下基片倾斜角度为 60°时薄膜磁致伸缩系数达到最大值 1.02×10-4,并且随着基片倾斜角度的增大 TbFe薄膜的易磁化方向由垂直膜面方向逐渐转向平行膜面方向。这是由于倾斜基片溅射形成的倾斜的薄膜柱状微结构产生的形状各向异性引起的。     

磁过滤阴极电弧技术沉积高sp3键含量四面体非晶碳薄膜的工艺优化研究

通过对不同基片偏压下磁过滤器电流对四面体非晶碳(ta-C)薄膜sp3键含量影响的研究,探讨了磁过滤阴极电弧技术制备高sp3键ta-C薄膜优化工艺条件.在不同的基片偏压下,薄膜沉积率随着磁过滤器电流增大而增大.当基片偏压为200V时,磁过滤器电流从5A增大至13A,ID/IG从0.18增加到0.39;当基片偏压500V时,ID/IG从1.3增加到2.0;证明随着磁过滤器电流的增大,薄膜中的sp3键含量在减少,sp2键及sp2团簇在逐渐增加.研究表明除了基片偏压,ta-C薄膜sp3键含量与制备工艺中磁过滤电流也具有及其密切的关联.因此,基片偏压与磁过滤器电流是ta-C薄膜制备中需要优化的工艺条件.优化和选择合适的基片偏压与磁过滤器电流对ta-C薄膜的大规模工业化生产应用具有极其重要的意义.     

提高家用热水器电磁阀抗蚀性的途径

家用热水器的电磁阀长期与煤气接触，易受煤气中氯离子和硫离子等杂质的腐蚀。采用磁射频反应溅射技术，对电磁阀的表面进行了真空渗氮处理，并在表面沉积性能优良的氮化铝（ＡｌＮ）钝化膜，试验表明，该方法可提高电磁阀的抗蚀性。     

退火对低温射频磁控溅射Ba铁氧体薄膜结构及磁特性的影响

用RF磁控溅射法，在纯Ar气中，硅基片不加热的情况下，制备了Ba铁氧体薄膜，研究了退火温度对薄膜c轴垂直取向、结构及磁特性的影响，结果表明薄膜在700℃氧气中退火可获得良好c轴垂直膜面的择优取向，该薄膜的饱和磁化强度和矫顽力分别为Ms=296emu／cm3，Hc=308761A／m。退火温度过低或过高，都不利于形成c轴垂直膜面的择优取向。     

退火对低温射频磁控溅射Ba铁氧体薄膜结构及磁特性的影响

用ＲＦ磁控溅射法，在纯Ａｒ气中，硅基片不加热的情况下，制备了Ｂａ铁氧化薄膜，研究了退火温度对薄膜Ｃ轴垂直取向、结构及磁特性的影响，结果表明薄膜在７００℃氧气中退火可获得良好Ｃ轴垂直膜同的择优取向，该薄膜的饱和磁化强度和矫顽力分别为Ｍｓ＝２９６ｅｍｕ／ｃｍ＾３，Ｈｃ＝３０８７６１Ａ／ｍ。退火温度过低或过高，都不利于形成Ｃ轴垂直膜面的择优取向。     

YIG薄膜制备方法研究

就工艺，测试结果，性能等方面综述了钇铁石榴石YIG（Yttrium Iron Garnet)薄膜的制备方法，包括Sol-Gel、CVD、溅射、PLD、LPE等。从YIG复合薄膜的制备、基片选择等角度，提出通过提高YIG薄膜制品的磁光性能从而改善磁光器件整体性能的新思路。     

溅射工艺条件对TbFeCo/Pt薄膜磁性能的影响

采用射频磁控溅射法在玻璃基片上成功制得了TbFeCo/Pt非晶垂直磁化膜,系统研究了溅射工艺参数对TbFeCo薄膜磁性能的影响.振动样品磁强计测量结果表明:Tb含量在补偿成分点附近,采用较低的溅射氩气压与Pt底层,有利于提高TbFeCo薄膜的磁性能;当Tb含量为0.24,溅射功率为300W,溅射气压为0.53Pa,薄膜厚度为140nm时,TbFeCo/Pt薄膜矫顽力达到476kA/m,饱和磁化强度为151kA/m,剩磁矩形比超过0.8,该薄膜有望用作高密度光磁混合记录介质.     

专利信息

一种含Cu、Mg、Zn、Mn和Cr的铝合金磁盘基片材料于1993年7月9日获日本专利,专利号为JP 93045659-B。 该合金的成分(wt％)为:Cu 0.01～0.03、Mg2～6、Zn0.05～2.0、Mn0.01～0.05、Cr 0.01～0.05。杂质元素分别为:Si0.1％、Fe0.1％、Ti0.02％,其它不可避免的杂质含量不大于0.02％。     

Numerical study of near-field writing on a phase-change optical disk

Absorption in the phase-change layer of an optical disk located in the near field of a Fabry-Perot laser diode is studied with a combination of finite-difference time domain (FDTD) analysis and a phenomenological laser model that predicts the operational characteristics of a laser diode. Some numerical simulations are performed and results are presented. In addition, the combined FDTD/laser-simulation model is described briefly.     

Vector diffraction analysis of optical disk readout

The optical disk readout signals from ROM disks are presented by use of a rigorous three-dimensional vector diffraction method. The optical disk is modeled as a crossed metal grating without restriction on the form of the information marks, and the permittivity of the metal is taken into account. The diffracted field from the disk is obtained by means of decomposing the focused incident beam into a spectrum of plane waves and then calculating the diffracted plane waves for each respective incident component. The readout signal is obtained by integration of the energy-flux density of the diffracted field according to the detection scheme of the optical disk system. A typical digital versatile disk (DVD) system is applied with this theory, and the result is far from that of scalar diffraction theory.     

Dual-wavelength optical head with a wavelength-selective filter for 0.6- and 1.2-mm-thick-substrate optical disks

A dual-wavelength optical head, believed to be new in design, for 0.6- and 1.2-mm-thick-substrate optical disks was developed by use of 650- and 780-nm-wavelength light and a wavelength-selective filter, which reduces the spherical aberration that is due to the difference in substrate thicknesses and restricts the numerical aperture for 780-nm-wavelength light. According to this configuration, both high light power efficiency and wide image field characteristics are obtained, which are suitable not only for read-only but also for recordable or rewritable optical disk systems. A reading operation for a digital video disc and for a compact disc and a recording operation for a phase change optical disk were successfully demonstrated.     

Maximum fiber coupling efficiency and optimum beam size in the presence of random angular jitter for free-space laser systems and their applications

Free-space laser communication systems use optical-fiber-based technology such as optical amplifiers, receivers, and high-speed modulators. In these systems using single-mode fibers, the fiber coupling efficiency is one of the most significant issues to be solved. Optimum relationships between a focused optical beam and mode field size of the optical fiber in the presence of random angular jitter are discussed in relation to fiber-coupled optical systems. Maximum fiber coupling efficiency is analytically derived with the optimum Airy disk radius normalized by the mode field radius as a function of random angular jitter. The fade level of fiber-coupled signals at desired fade probability is investigated. It is shown that the average bit error ratio significantly degrades with the random angular jitter normalized by the mode field radius larger than about 0.3 when the Airy disk size is optimally selected.     

Nonlinear model for an optical read-only-memory disk readout channel based on an edge-spread function

A point-spread function (PSF) is commonly used as a model of an optical disk readout channel. However, the model given by the PSF does not contain the quadratic distortion generated by the photo-detection process. We introduce a model for calculating an approximation of the quadratic component of a signal. We show that this model can be further simplified when a read-only-memory (ROM) disk is assumed. We introduce an edge-spread function by which a simple nonlinear model of an optical ROM disk readout channel is created.     

阵列波导光栅解复用器光谱响应特性分析

基于单模光波导本征模场及其端面衍射场分布的高斯近似表达,推导出两个端面非接触光波导耦合的耦合系数的函数表达式,并基于此推导出阵列波导光栅解复用器的简单光谱响应效率的函数表达式。建立了分析阵列波导光栅解复用器光谱响应特性的简洁数学模型,阐明了阵列波导光栅解复用器对通道中心频率的响应度和相邻信号通道间的串扰与基本参数的关系,为设计和分析阵列波导光栅解复用器提供了理论基础。     

准线性区光盘聚焦自动预搜索机制的研究

线性区自动预搜索是各类光盘系统中聚焦伺服系统需要完成的重要功能。在分析了现有的线性区自动预搜索方法的基础上，提出并具体阐述了准线性区光盘聚焦自动预搜索机制，充分利用了光盘聚焦误差信号曲线的正负反馈特性，得到一种简单实用而又稳定可靠的自动预搜索方法。     

Influence of substrate thickness on optical disk readout

I consider the influence of different substrate thicknesses on the signal obtained from an optical disk. Two solutions are presented for the reading of different disk types. In one situation a substrate thickness change for disks with equal density is made inoffensive by introduction of a combined amplitude-phase mask in the pupil of the readout objective. In a second situation, where the different thickness is accompanied by a change in optical density, a specific selection in the far field of the detected radiation has proven to be adequate.     

Visible imaging characteristics of the space target based on bidirectional reflection distribution function

A modelling method for visible imaging characteristics of a space target is presented. Background radiation of a space target consists of direct solar radiation, reflected radiation from the earth and the moon, and that from other stars. The target surface was divided into grids and the light reflection properties of each grid are described by introducing a bidirectional reflection distribution function (BRDF) model obtained in advance. Then a mathematical model for the visible imaging properties of the space target was built using given parameters of the optical detection system. Visual surfaces of the target to detection system were determined by a vector coordinate method. Simulation of the target optical imaging characteristics in orbit was achieved according to its given physical dimensions and parameters. The results show the method is feasible and robust for optical characteristics of the space target. It can provide a facility for real-time analysis of optical imaging characteristics of space targets.     

磁场调制直接重写磁光存储介质的记录特性研究

用直流共溅射方法制备了富稀土－过渡族金属非晶态合金薄膜，用数值计算的方法计算了激光照射下多层膜结构盘片的温度场分布，分析了盘片材料成分和结构对热磁记录的影响，对盘片结构进行了优化设计并选定了合适的磁光层和电介质层厚度。实验盘片可在低偏场和低激光功率下记录，盘片的读写性能基本符合２．５英雨可擦重写磁光盘（ＭｉｎｉＤｉｓｋ）的使用要求。