Preconditioning, write width, and recording properties of Co-Cr-Pt-O perpendicular media with various underlayer designs

The effect of magnetic "preconditioning" on the recording performance of perpendicular media is investigated. Furthermore, the dependence of the magnetic write width (MWW) of shielded-pole heads (SPH) on soft-underlayer (SUL) type and thickness (t/sub SUL/) and the recording performance of perpendicular media with thin SULs are examined. The MWW dependence on SUL structure is influenced by the pole-to-trailing shield spacing. For a wide-gap (/spl sim/80 nm) SPH, thick single-layer, SULs are preferred. For a narrow-gap (/spl sim/50 nm) SPH, MWW is less sensitive to the SUL type. For both narrow and wide-gap SPH and for media with an antiferromagnetically-coupled SUL, MWW is reduced for t/sub SUL/<100 nm. Comparable performance is achieved relative to media with t/sub SUL//spl sim/150 nm.     

Modeling the effects of write field rise time on the recordingproperties in thin film media

A theory for including the effect of finite write field rise time in the calculation of written transition parameters for thin film media has been developed. Calculated dependence of transition parameter, overwrite and nonlinear transition shifts on the write field rise time are shown. Model results are compared with measured values for a thin film inductive head at different write current rise times and varying disk rotational velocity, for fixed linear density and flying height. The theory has also been used to calculate the amount of precompensation required to reduce the nonlinear shift to near zero     

Patterned polymer carpets

For the development of polymer carpets as active devices for micro- and nanotechnology, a control of the polymer carpet morphology and especially control of the stimulus responsive polymer brush is needed. Here, we report on the first example for the fabrication of patterned polymer carpets. On a two-dimensional framework of fully crosslinked and chemically patterned nanosheets, polymer brushes of styrene and 4-vinyl pyridine were grafted by self-initiated surface photopolymerization and photografting (SIPGP). It was found that polymer grafting by SIPGP occurred over the entire nanosheets but with a preferred grafting on the amino functionalized nanosheet areas. This results in continuous polymer carpets with an intact nanosheet framework but with amplification of the chemical patterning into a three dimensional topography of the grafted polymer brush. In the case of negative patterned nanosheets, the patterned carpet could be prepared as freestanding ultrathin membranes. Furthermore, swelling experiments with poly(4-vinyl pyridine) carpets showed that the patterns induces a directional buckling of the flexible polymer carpet. This may open the possibility of the development of micro- or nanoactuator devices with anisotropic responds upon environmental changes.     

Patterned armor performance evaluation

Patterned armor is characterized by an array of repeating cells, such as tiled ceramic armor or reactive armor boxes. Performance characteristics of an ideal patterned armor with respect to multiple hits are discussed, and the types of single-shot ballistic data needed to quantify that performance are presented. An approach to use these data is developed to provide a quantitative measure (probability of nonperforation after a given number of impacts) of the patterned armor performance against multiple impacts. This performance measure can then be compared to a well-posed multiple-hit criterion to assess whether the patterned armor meets the criterion.     

纳米纤维选择性沉积

静电纺丝中的纳米纤维选择性沉积技术可提高材料的利用率,减少工序,降低成本.制作分别带圆、矩形和三角形孔三种不同形状的接地金属板作为收集板.实验结果表明:对于三种不同形状的孔,孔顶角(三角形和矩形)和孔周围的纳米纤维分布密度都比孔中间位置的大得多.这是由于喷射到收集板孔附近的带正电荷纳米纤维在孔周围不均匀电场作用下进行选择性沉积.在金属板上覆盖一层80微米厚塑料薄膜来沉积纳米纤维可得到同样的结果.该选择性沉积技术将为未来批量化纳米纤维喷射选择性沉积提供试验依据.     

聚苯乙烯一维纳米阵列的图案化

采用紫外线光刻技术在阳极氧化铝模板(AAO)上生成预设图案,用物理浸润的方法在图案化的模板上生长聚苯乙烯,最后用NaOH和磷铬酸溶液分别溶解模板.采用扫描电子显微镜(SEM)和电子能谱(EDS)分析.结果表明,制备的图案是直径5μm的圆形组成,圆形图案中心之间距离是10μm,每个圆中长满一维纳米阵列,其纳米特性没有变化.     

Flexible disk--Read/write head interface

The response of a rotating flexible magnetic disk interacting with a stationary read/write head is analyzed using a theory that accounts for the effects of bending forces, membrane forces of rotation, and inertia forces. The solution thus obtained is coupled with the solution to the Reynolds equation to determine the pressure profile and film thickness (flying height) between the head and disk.     

Patterned porous silicon formed with photolithography

Porous silicon is a fascinating light-emitting material among silicon-related materials. We have challenged to form a patterned porous silicon layer for the purpose of the micro optical devices with the help of photolithography. Photoresist has been used as a mask that prevented the formation of porous silicon. We achieved square patterned porous silicon with a precision of 30 m. We also found a problem that the formation of porous silicon also proceeded under the mask partly.     

Integrated Circuits Comprising Patterned Functional Liquids

Solid‐state heterostructures are the cornerstone of modern electronics. To enhance the functionality and performance of integrated circuits, the spectrum of materials used in the heterostructures is being expanded by an increasing number of compounds and elements of the periodic table. While the integration of liquids and solid–liquid interfaces into such systems would allow unique and advanced functional properties and would enable integrated nanoionic circuits, solid‐state heterostructures that incorporate liquids have not been considered thus far. Here solid‐state heterostructures with integrated liquids are proposed, realized, and characterized, thereby opening a vast, new phase space of materials and interfaces for integrated circuits. Devices containing tens of microscopic capacitors and field‐effect transistors are fabricated by using integrated patterned NaCl aqueous solutions. This work paves the way to integrated electronic circuits that include highly integrated liquids, thus yielding a wide array of novel research and application opportunities based on microscopic solid/liquid systems.     

ZnO纳米线阵列的图形化生长

采用光刻和射频磁控溅射技术在Si衬底上制备了图形化的ZnO种子层薄膜。分别采用气相榆运和水热合成法，制备了最小单元为30μm的图形化的ZnO纳米线阵列。X射线衍射（XRD）分析显示单晶纳米线阵列具有高度的c轴[001]择优取向生长性质，从扫描电子显微镜（SEM）照片看出，阵列图形完整清晰，边缘整齐，纳米线阵列在室温下光致发光（PL）谱线中在380hm左右具有强烈的紫外发射峰，可见光区域发射峰得到了抑制，证明ZnO纳米线阵列氧空位缺陷少，晶体质量高。     

Magnetoresistive read/write channel models

We studied the magnetic read/write channel with a magnetoresistive (MR) read head at a normalized channel density range of 2.5-3.0, observing and modeling partial erasure and nonlinear transition shift. The asymmetry of the MR head had a significant effect on the channel. We applied the transition-width-reduction model, the partial-erasure-plus-transition-shift model, and the Volterra model to the MR read/write channel, and evaluated the accuracy of these models on the basis of parameters obtained from experimental data. In order to consider the asymmetry of the MR head, we introduced a nonlinear MR head model into the read/write channel. These modified models achieved higher accuracy. Of all the models considered, the Volterra model provides the largest improvement over the linear model     

Patterned radial GaAs nanopillar solar cells

Photovoltaic devices using GaAs nanopillar radial p-n junctions are demonstrated by means of catalyst-free selective-area metal-organic chemical vapor deposition. Dense, large-area, lithographically defined vertical arrays of nanowires with uniform spacing and dimensions allow for power conversion efficiencies for this material system of 2.54% (AM 1.5 G) and high rectification ratio of 213 (at ±1 V). The absence of metal catalyst contamination results in leakage currents of ～236 nA at -1 V. High-resolution scanning photocurrent microscopy measurements reveal the independent functioning of each nanowire in the array with an individual peak photocurrent of ～1 nA at 544 nm. External quantum efficiency shows that the photocarrier extraction highly depends on the degenerately doped transparent contact oxide. Two different top electrode schemes are adopted and characterized in terms of Hall, sheet resistance, and optical transmittance measurements.     

Patterned graphone--a novel template for molecular packing

Precise positioning and packing of nanoscale building blocks is essential for the fabrication of many nanoelectro-mechanical devices. Carrying out such manipulations at the nanoscale still remains a challenge. Here we propose the use of graphone domain arrays embedded in a graphene sheet as a template to precisely position and pack molecules. Our atomistic simulations show that a graphone domain is able to adopt well-defined three-dimensional geometries, which in turn create 'energy wells' to trap molecules by means of physisorption. Using the C60 molecule as a model block, the stable trapping conditions are identified. The present work presents a novel route to position and pack molecules for nanoengineering applications.     

Adsorption Within and On Regularly Patterned Substrates

Advances in nanofabrication techniques have made possible the realization of highly-regular patterned surfaces. In this paper, we review recent experiments involving the adsorption of simple classical fluids in regular arrays of microscopic channels with different cross-section profiles and of straight, not interconnected mesopores, which show a rich interplay between geometry and physics. The attention will be devoted to the features of wetting transitions in microchannels and of capillary filling in cylindrical mesopores.     

图案化磁记录介质

在分析传统磁记录在高密度化过程中遇到的困难的基础上,指出了未来超高密度磁存储的方向,着重分析了图案化磁记录(patterned magnetic recording)对介质的要求,并简要介绍了图案化介质的制备技术.