Effect of sintering on the optical properties of SiO2 colloidal crystal multilayers

High-quality SiO2 colloidal crystal multilayers were fabricated from ethanol solutions by the vertical deposition method and the effect of sintering on the optical properties of the samples was investigated. Optical properties,which are determined by the photonic band structure, weres tudied by means of light transmission and reflection measurements. The morphology of the samples was characterized by scanning electron microscopy (SEM). SEM images illustrate the ordered close package of the spherical colloids in planes parallel to the substrate surface. In addition, the sampie is crackless as a result of an appropriate drying rate. It is shown that with the increase of the sintering final temperature, though the depth and the width of the peak of Bragg diffraction of the sample vary vastly, the peak produces few blue shifts. Optical measurement results were compared favorably to the microstructural properties of the colloidal crystal multilayers.     

Structure and transport studies on nanometer YBCO/PBCGO multilayers

We have fabricated M doped （M = Al, Co, Fe, Ga, Ni and Zn） PrBa2Cu3O7（PBCO）, i.e. PrBa2（CU1-xMx）3O7. The doping levels x are 0.05, 0.10, 0.15, and 0.20. X-ray data indicated no significant second phase for substituting Cu by Al, Co, Fe and Ga up to 20%. However impurity phases were detected for Ni and Zn substituted samples with doping levels equal to and higher than 15%. At 77 K the electrical resistivity of these compounds is orders in magnitude higher than that of PBCO. We also found that although the lattice parameters in the doped samples differ from PBCO, all samples remain orthorhombic. The lattice parameters of the doped sample are very close to those of YBa2CU3O7-δ （YBCO） and PBCO. For this reason these compounds are better materials to be used as the I-layer for YBCO SIS junctions. Results of structural and transport studies on 2000 A thick PrBa2[Cu0.80G0.2]3O7 （PBCGO） and YBCO/PBCGO multilayers are presented in this paper.     

Solvent-assisted polymer micro-molding

The micro-molding technology has played an important role in fabrication of polymer micro-patterns and development of functional devices. In such a process, suitable solvent can swell or dissolve the polymer films to decrease their glass transition temperature （Tg） and viscosity and thereby improve flowing ability. Consequently, it is easy to obtain the 2D and 3D patterns with high fidelity by the solvent-assisted micro-molding. Compared with the high temperature molding, this technology overcomes some shortcomings such as shrinking after cooling, degradation at high temperature, difficulty in processing some functional materials having high Tg, etc. It can be applied to making patterns not only on polymer monolayers but also on polyelectrolyte multilayers. Moreover, the compressioninduced patterns on the multilayers are chemically homogenous but physically heterogeneous. In this review, the controlling factors on the pattern quality are also discussed, including materials of the mold, solvent, pressure, temperature and pattern density.     

TiN/AlN纳米多层膜的制备及力学性能

采用多靶反应磁控溅射法制备了ＴｉＮ／ＡｌＮ纳米多层膜,并通过ＸＲＤ、ＴＥＭ和显微硬度计对多层膜的调制结构和力学性能进行了研究．结果表明,反应磁控溅射法制得的纳米多层膜调制界面平直清晰;薄膜的硬度随其调制周期Λ的减小而单调增加,硬度在Λ＝２ｎｍ时达到最大值ＨＫ３２．９３ＧＰａ．     

巨磁阻效应研究的最近进展

本文综述了近几年来巨磁阻材料的研究进展,并将其粗略的分为五种类型,简要分析了每种类型的物理机制。     

"La0.67 Ca0.33MnO3/Ag/Fe"多层膜的制备及性能研究

利用磁控溅射,将磁电阻材料Ｌａ０．６７ Ｃａ０．３３ＭｎＯ３（Ｔｃ＝ ２６７℃）与金属Ａｇ、Ｆｅ 等材料相结合,制成了多层膜（磁电阻材料／非磁金属／铁磁金属）,测得了三层膜“Ｌａ０．６７ Ｃａ０．３３ＭｎＯ３／Ａｇ／Ｆｅ”的巨磁电阻效应（ＭＲ＝ ８６％ ,Ｂ＝ ０．８Ｔ,Ｔ＝ １５０Ｋ）．     

Cu/Ni多层膜的调制波长与力学性能的关系

为研究Cu/Ni多层膜的调制波长与力学性能的关系,采用计算机控制的单槽双脉冲控电位沉积系统,在Cu基体上沉积Cu/Ni多层膜,分别采用扫描电镜和纳米压痕技术对Cu/Ni多层膜的截面和硬度进行了测试.结果表明:电沉积方法制备的Cu/Ni多层膜具有良好的周期结构;在调制波长为37 nm时硬度达到极值;在调制波长小于37 nm时其硬度值明显下降.实验结果符合理论分析中多层膜的硬度随调制波长的变化规律,但临界调制波长大于理论计算结果.     

具有层间耦合反铁磁阻挫系统的热力学性质

本文研究了具有充分阻挫的梅森堡反铁磁三角晶格的热力学性质，同时讨论了系统的低温相交行为和自旋的元激发谱，其结果与蒙特卡罗模拟结果符合的较好。     

NiFe／Cu多层膜的巨磁电阻效应

采用磁控溅射方法在玻璃基片上沉积NiFe／Cu多层膜．在室温下测量到其巨磁电阻随cu层厚度振茴的第一峰和第二峰，相应的峰值分别为19%和11%．研究了巨磁电阻隧NiFe层厚度及多层膜总周期数Ⅳ的变化规律。     

Recent Advances in Hard, Tough, and Low Friction Nanocomposite Coatings

Nanocomposite coatings demonstrate improved friction and wear responses under severe sliding conditions in extreme environments. This paper provides a review how thin film multilayers and nanocomposites result in hard, tough, low-friction coatings. Approaches to couple multilayered and nanocomposite materials with other surface engineering strategies to achieve higher levels of performance in a variety of tribological applications are also discussed. Encapsulating lubricious phases in hard nanocomposite matri- ces is one approach that is discussed in detail. Results from state-of-the-art ＂chameleon＂ nanocomposites that exhibit reversible adaptability to ambient humidity or temperature are presented.