EM液细胞的早期发展过程中，郑教授A.感谢保罗Alivisatos和乌尔里希·达门博士的有益讨论。她是美国能源部办公室科学的早期职业研究计划的支持表示感谢。

1。微细加工的液体池<ol><li>准备的硅晶片（p-掺杂的，厚度（100微米）和4英寸直径）和清洁程序的使用标准的晶片浴清洗晶片。 </li><li>存款低应力氮化硅薄膜（厚度为20nm），通过低压化学汽相淀积（LPCVD）方法在硅晶片的两侧上。用于沉积，它允许生长的富硅氮化物（ 的 SiN x中，x &lt;4/3）的自定义开发的配方。 </li><li>制作底部的芯片（2.6×2.6毫米，3毫米直径）的观看窗口（1×50微米）和最佳的芯片（2.6×2.6毫米，3毫米直径）与观察窗（1×50微米）和两个储层（0.6×1.2×0.1毫米），由标准的制造工艺，包括光刻构图的 SiN x膜的等离子体蚀刻（使用SF 6作为活性气体），KOH湿etchin的序列后克的暴露的硅晶片等我们使用的最常见的光刻工艺，如旋涂的光致抗蚀剂（1分钟纺丝速度为每分钟3000转的正性光致抗蚀剂与光致抗蚀剂的厚度是大约1微米），紫外线曝光下的Cr掩膜的液体的细胞，使用的显影液和定影液（去离子水）等的光刻图案形成有用于旋涂的光致抗蚀剂和显影剂的图案化的不同的选择。而且，相应的参数的过程也可以变化。由于图案的特征是相对大（几百微米或更大），其过程是容易完成。的KOH溶液的制备是用氢氧化钾：水的重量比为1:2将氢氧化钾功率溶解到去离子水中。在蚀刻期间，被保持在80℃的KOH溶液。可以达到每分钟的蚀刻速率为1μm。 的 SiN x膜，是一种理想的防护面具KOH蚀刻硅。由于etching行使用，单独的芯片连接的KOH蚀刻后的蚀刻晶片的细线。枚芯片，可以容易地分离，从晶片，使用尖锐的镊子为后续处理。没有切割过程是必要的。 </li><li>存款铟间隔的平面侧的底部芯片。首先，按照类似的过程在1.3做光刻图案化的芯片。协助处理芯片，坚持独立的芯片（可以是一段几个芯片），使用光致抗蚀剂上的薄板玻璃，让它风干5分钟前旋涂，紫外线的照射等。二，清洁图案芯片O 2等离子体清洗1分钟，在50瓦的，第三，存款铟薄膜的厚度为100nm的芯片上，通过使用蒸发器;第三，剥离工艺进行生成铟隔板的。 </li><li>债券的底部和顶部芯片在一起。我们首先对齐两个氮化硅观景窗下的底部和顶部的芯片的光学microscope和施加约0.1 MPa的压力下，通过使用一个夹子。它需要的实践中，为了精确地对准彼此的顶部上的窗户。随后，液体细胞1小时，在真空烘箱中在120℃被烘烤。最后，我们收集细胞，并存储所制备的细胞，在真空干燥器中，以便将来使用。 </li></ol>是图1中所示的整个制造过程。我们所有的制造工艺进行大学，加州大学伯克利分校的纳米加工实验室。 2。反应溶液的制备我们准备反应液的生长的Pt 3 Fe的纳米棒作为一个例子。铂（Ⅱ）乙酰丙酮化物（20毫克/毫升）和铁（II），乙酰丙酮（20毫克/毫升），溶解在正十五烷，油胺（7:3体积/体积），十五烷胺，油胺或它们的混合物的溶剂混合物中，并油酸（，6:3:1体积/体积/体积），用于比较surfactan吨的效果。 3。负载反应解决方案<ol><li>约50 NL反应溶液装入一个在液体中的细胞的储层通过使用注射器和特氟隆的碳纳米管（购买从Cole-Parmer公司，IL）。然后，其他的水库中相同的方式填充。 </li><li>通过毛细管力，被吸入到反应溶液中的约30复数细胞和形成的液体层（〜100nm）的2的氮化硅膜之间夹持在观看窗口。 </li><li>使用一个薄的铜盖（〜50μm的TEM网格的单个时隙0.6毫米直径的孔，这是从大于tEDD培拉公司购买），随后被密封的液体细胞。真空润滑脂施加在一个侧盖和环氧树脂用于密封的边缘的液体的细胞。最终的液体单元的总厚度为约250-300微米。 </li></ol> 4。将液体池TEM <ol><li>工作在300千伏和FEI一个JEOL 3010透射电子显微镜单色F20 UT TEC奈为200 kV，用于原位成像。 </li><li>装入的液体细胞作为一个标准的TEM样品的显微镜成像。 </li></ol> 5。实时TEM成像<ol><li>调整显微镜以一个完美的高分辨率TEM成像条件，和一个电子束电流密度为1-8×10 5 A / m 2的过程中保持的实时成像。 </li><li>对PTFE系统，通过浇铸的液体层上的电子束，可以启动的纳米颗粒的成核和生长。 </li><li>的VirtualDub软件结合与加坦DigitalMicrograph软件被用来记录的纳米粒子动力学。 </li></ol>

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没有利益冲突的声明。

洁净室中的半导体器件，其中，已经完成了所有的制造工序。 铟的沉积之前，O 2等离子体清洗的筹码是必要的，以消除表面上的有机残基。因此，高品质的铟间隔件可以实现，从而可以提高顶部和底部芯片接合和泄漏游离液体的细胞的产率。 约13 nm厚的超薄膜硅氮化物观景窗是一键实现高空间分辨率。处理这种液体细胞时，需要特别小心，以避?...

他们的母语环境的实时性和的成像生物材料在液体中的化学反应的研究一直在研究领域中1-5的重大利益。由于透射电子显微镜（TEM），通过液体TEM成像的空间分辨率高，吸引了很多关注4,5。然而，它一直是图像的液体样品TEM一个巨大的挑战，因为传统的显微镜操作在高真空环境。此外，液体样品必须足够薄，以允许电子束通过。 Williamson 等6报告为5nm的分辨率，使用电化学的液晶单元在TEM中操作，可以实现与电化学沉积的Cu成像。德容格等人 1能够图像serveral的微米厚的水生物样品通过使用扫描透射电子显微镜（S）。对比度低的生物样品的时间是不作为一个问题提出，由于黄金纳米粒子作为标记成像。粘稠液体样品是不是一个问题，因为STEM成像模式和纳米级分辨率达到了。最近，我们开发了一种自足的液晶单元，它允许实时TEM成像在液体中的胶体粒子与亚纳米分辨率5,7。这些新开发的的液体细胞，提供了更好的分辨率和更快的TEM成像（每秒30帧的高分辨率STEM成像尚未实现），使人们有可能在液体中的胶体纳米粒子动力学研究。的液体的细胞适合在一个标准的TEM保持器和可作定期TEM样品。少量的液体（约30皮升），可以检查在原位下一个扩展化学反应。可以应用于各种成像和分析（ 即 ，能量色散型X射线光谱法）技术。由于所述观察窗的总厚度（包括膜和液体层），可以被控制为100纳米或更低，没有金纳米微粒标记的生物样品（ 即蛋白）在液体水的直接成像也已取得8。 在过去的二十年中，已经有显著成绩的合成及应用胶体纳米晶9-11。但是，了解如何纳米粒子成核，生长和相互影响的，在液体中的主要经验，主要是基于易地分析11-13。液体细胞TEM我们的发展提供了一个独特的平台，研究纳米颗粒在液体中的动态过程的原位 5,7,14,15。 我们制作一个自包含的液体电池，使用超薄硅晶片（100微米），由连续的微细加工过程。它包括沉积氮化硅膜，光刻构图，晶片蚀刻，隔离物的沉积，和细胞粘接等约50纳升的反应溶液装入一个蓄水池，通过毛细管力被吸入到单元格。我们填充其它贮存的与另一50纳升的液体。然后，将电池被密封，并加载到原位成像显微镜。显微镜内部，液体夹着两个氮化硅膜（共约30皮升），可以检查。当电子束穿过的薄液体层，可以实时监测的纳米颗粒在液体中的动态过程。可诱导的纳米颗粒的成核和生长，通过电子束5,7或反应在某些情况下，可以由外部加热源14,16触发。当电子束损坏是一个关注，低电子束电流（剂量）应该被使用。 由于液态电池制造的硅微加工工艺和大批量，在膜或液体的变化个体间的液体细胞的厚度L6小型会议室。有基本微细培训的所有研究可以成功地使液体细胞。液体处理技术，并在 TEM 原位操作，也可以掌握后实践。据指出，除了使用的氮化硅膜作为观察窗时，可以使用其它材料，如二氧化硅，硅或碳（包括石墨烯）可以作为膜窗口，以及17日至19日 。由于我们的液体使用小的观景窗， 即 1 x 50微米，没有鼓鼓的膜细胞已被观察到。而且，液晶单元也是强大的操作， 即 ，低于1％的液体细胞已在实验过程中的破窗。此外，液体层的厚度，也可以被灵活地调谐，通过改变沉积的铟间隔件的厚度。一个密封的液体样品制备过程中，电池可以维持几天无泄漏的液体。少量的液体可以几个小时检查下的电子束，它允许实时扩展化学反应的研究。 到目前为止，我们有许多独特的动态过程可视化的纳米颗粒在液体中，例如，Pt纳米粒子的长大和聚合5,15，扩散的纳米粒子在薄的液体20,21，双向纳米粒子的增长波动的14，环 ​​比增长3篇铁纳米棒纳米颗粒积木等，此外，我们也应用这种方法到其他领域， 例如 ，成像在液体水的蛋白质为2.7纳米的分辨率8。总之，我们的液体电池的TEM技术已被证明是一个非常宝贵的发展，在材料科学，物理学，化学和生物学的基本问题的研究范围很广。我们相信未来技术的进步和应用的液体TEM还有很大的空间，它必将是一个高IMPACT在广泛的科研。

<table border="1"><tbody><tr><td></td><td></td><td></td><td> 试剂 </td></tr><tr><td>乙酰丙酮铂（II） </td><td> Aldrich公司</td><td> 523038 </td><td></td></tr><tr><td>铁（II），乙酰丙酮</td><td> Aldrich公司</td><td> 413402 </td><td></td></tr><tr><td>十五烷</td><td> Aldrich公司</td><td> P3406 </td><td></td></tr><tr><td>油胺</td><td> Aldrich公司</td><td> O7805 </td><td></td></tr><tr><td>油酸</td><td>西格玛</td><td> O4137 </td><td></td></tr><tr><td></td><td></td><td></td><td> 设备 </td></tr><tr><td> TEM </td><td> JEOL </td><td> JEOL 3010 </td><td></td></tr><tr><td>单色器TEM </td><td> FEI </td><td> F20 UT TECNAI </td><td></td></tr></tbody></table>

revealing dynamic processes of materials in liquids using liquid cell transmission electron microscopy

最近开发的原位透射电子显微镜，它可以通过液体具有高空间分辨率成像，吸引了显着的利益，整个材料科学，物理学，化学和生物学的研究领域。关键技术是液体电池。我们制作液体细胞与薄的观景窗，通过一个连续的微细加工过程，包括氮化硅膜沉积，光刻构图，晶片蚀刻，细胞接合，等，一种液体的细胞与定期TEM网格的尺寸可以适合在任何标准的TEM样品架。约100纳升反应溶液装入水库，并通过毛细管力约30皮升的液体被吸入的观察窗口。然后，将电池被密封，并加载到原位成像显微镜。加入的TEM，电子束穿过两个氮化硅膜夹着的薄液体层。动态PROC俄塞克的纳米颗粒在液体中，如纳米晶体成核和生长，扩散和组装的纳米粒子，等，已在实时成像亚纳米级的分辨率。这种方法也适用于其他研究领域， 例如 ，成像在水中的蛋白质。液体细胞TEM必将发挥了重要作用，揭示材料的动态过程，在他们的工作环境。它也可能带来高的影响，在他们的母语环境中的生物过程的研究。

通过使用液晶单元TEM方法，我们已可视化的溶液生长的Pt 3铁纳米棒从纳米粒子积木图2示出描绘在不同的解决方案的情况下的Pt 3铁纳米棒的成长轨迹的顺序图像。假着色工艺使用Photoshop突出的纳米粒子。 当十五碳烷，油胺（7:3体积/体积）的溶剂混合物中，使用了三个不同的阶段的增长可以被识别（ 图2A）。首先，许多小的纳米粒子?...

Watch this Scientific Journal Video about Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy at JoVE.com

Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy

我们已经开发了一个自包含的液晶单元，它允许通过使用透射电子显微镜的液体的成像。纳米颗粒在液体中的动态过程，可以亚纳米分辨率的实时显示。

在液体中使用液体池透射电子显微镜揭示材料的动态过程

The recent development for in situ transmission electron microscopy, which allows imaging through liquids with high spatial resolution, has attracted ...

revealing-dynamic-processes-materials-liquids-using-liquid-cell

Research

JoVE Journal

Engineering

12.6K 次观看.  Lawrence Berkeley National Laboratory. 我们已经开发了一个自包含的液晶单元，它允许通过使用透射电子显微镜的液体的成像。纳米颗粒在液体中的动态过程，可以亚纳米分辨率的实时显示。

视频: Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy

Dynamic Pore-scale Reservoir-condition Imaging of Reaction in Carbonates Using Synchrotron Fast Tomography

Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve geologic seals and allow CO2 to escape. However, the dissolution processes at reservoir conditions are poorly understood. Thus, time-resolved experiments are needed to observe and predict the nature and rate of dissolution at the pore scale. Synchrotron fast tomography is a method of taking high-resolution time-resolved images of complex pore structures much more quickly than traditional &#181;-CT. The Diamond Lightsource Pink Beam was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 &#181;m resolution over a period of 2 hours. The images were segmented and the porosity and permeability were measured using image analysis and network extraction. Porosity increased uniformly along the length of the sample; however, the rate of increase of both porosity and permeability slowed at later times.

Synchrotron fast tomography was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 &#181;m resolution over a period of 2 h.

用同步快速反应层析成像动态孔隙规模油藏条件下成像碳酸盐

Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve ...

科研

工程学

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

通过扫描电子显微镜在半导体材料的扩展缺陷的全面表征

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

This protocol describes the operation of a liquid flow specimen holder for scanning transmission electron microscopy of AuNPs in water, as used for the observation of nanoscale dynamic processes.

使用扫描透射电子显微镜研究纳米大小的物体的动态过程中的液体

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a ...

Wicking Tests for Unidirectional Fabrics: Measurements of Capillary Parameters to Evaluate Capillary Pressure in Liquid Composite Molding Processes

During impregnation of a fibrous reinforcement in liquid composite molding (LCM) processes, capillary effects have to be understood in order to identify their influence on void formation in composite parts. Wicking in a fibrous medium described by the Washburn equation was considered equivalent to a flow under the effect of capillary pressure according to the Darcy law. Experimental tests for the characterization of wicking were conducted with both carbon and flax fiber reinforcement. Quasi-unidirectional fabrics were then tested by means of a tensiometer to determine the morphological and wetting parameters along the fiber direction. The procedure was shown to be promising when the morphology of the fabric is unchanged during capillary wicking. In the case of carbon fabrics, the capillary pressure can be calculated. Flax fibers are sensitive to moisture sorption and swell in water. This phenomenon has to be taken into account to assess the wetting parameters. In order to make fibers less sensitive to water sorption, a thermal treatment was carried out on flax reinforcements. This treatment enhances fiber morphological stability and prevents swelling in water. It was shown that treated fabrics have a linear wicking trend similar to those found in carbon fabrics, allowing for the determination of capillary pressure.

An experimental method to measure geometrical parameters and the apparent advancing contact angles describing capillary wicking in unidirectional synthetic and natural fabrics is proposed. These parameters are mandatory for the determination of the capillary pressures that must be taken into account for liquid composite molding (LCM) applications.

吸湿排汗试验单向织物：毛细管参数的标准评价在液体复合成型工艺毛细管压力

During impregnation of a fibrous reinforcement in liquid composite molding (LCM) processes, capillary effects have to be understood in order to identify ...

Characterization of Ultra-fine Grained and Nanocrystalline Materials Using Transmission Kikuchi Diffraction

One of the challenges in microstructure analysis nowadays resides in the reliable and accurate characterization of ultra-fine grained (UFG) and nanocrystalline materials. The traditional techniques associated with scanning electron microscopy (SEM), such as electron backscatter diffraction (EBSD), do not possess the required spatial resolution due to the large interaction volume between the electrons from the beam and the atoms of the material. Transmission electron microscopy (TEM) has the required spatial resolution. However, due to a lack of automation in the analysis system, the rate of data acquisition is slow which limits the area of the specimen that can be characterized. This paper presents a new characterization technique, Transmission Kikuchi Diffraction (TKD), which enables the analysis of the microstructure of UFG and nanocrystalline materials using an SEM equipped with a standard EBSD system. The spatial resolution of this technique can reach 2 nm. This technique can be applied to a large range of materials that would be difficult to analyze using traditional EBSD. After presenting the experimental set up and describing the different steps necessary to realize a TKD analysis, examples of its use on metal alloys and minerals are shown to illustrate the resolution of the technique and its flexibility in term of material to be characterized.

This paper provides a detailed method to characterize the microstructure of ultra-fine grained and nanocrystalline materials using a scanning electron microscope equipped with a standard electron backscatter diffraction system. Metal alloys and minerals presenting refined microstructures are analyzed using this technique, showing the diversity of its possible applications.

超细晶和纳米晶材料的表征采用透射菊池衍射

One of the challenges in microstructure analysis nowadays resides in the reliable and accurate characterization of ultra-fine grained (UFG) and ...

A Method for Obtaining Serial Ultrathin Sections of Microorganisms in Transmission Electron Microscopy

Observing cells and cell components in three dimensions at high magnification in transmission electron microscopy requires preparing serial ultrathin sections of the specimen. Although preparing serial ultrathin sections is considered to be very difficult, it is rather easy if the proper method is used. In this paper, we show a step-by-step procedure for safely obtaining serial ultrathin sections of microorganisms. The key points of this method are: 1) to use the large part of the specimen and adjust the specimen surface and knife edge so that they are parallel to each other; 2) to cut serial sections in groups and avoid difficulty in separating sections using a pair of hair strands when retrieving a group of serial sections onto the slit grids; 3) to use a 'Section-holding loop' and avoid mixing up the order of the section groups; 4) to use a 'Water-surface-raising loop' and make sure the sections are positioned on the apex of the water and that they touch the grid first, in order to place them in the desired position on the grids; 5) to use the support film on an aluminum rack and make it easier to recover the sections on the grids and to avoid wrinkling of the support film; and 6) to use a staining tube and avoid accidentally breaking the support films with tweezers. This new method enables obtaining serial ultrathin sections without difficulty. The method makes it possible to analyze cell structures of microorganisms at high resolution in 3D, which cannot be achieved by using the automatic tape-collecting ultramicrotome method and serial block-face or focused ion beam scanning electron microscopy.

This study presents reliable and easy procedures for obtaining serial ultrathin sections of a microorganism without expensive equipment in transmission electron microscopy.

一种在透射电镜中获取微生物连续超薄切片的方法

Observing cells and cell components in three dimensions at high magnification in transmission electron microscopy requires preparing serial ultrathin ...

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

An analog, macroscopic method for studying molecular-scale hydrodynamic processes in dense gases and liquids is described. The technique applies a standard fluid dynamic diagnostic, particle image velocimetry (PIV), to measure: i) velocities of individual particles (grains), extant on short, grain-collision time-scales, ii) velocities of systems of particles, on both short collision-time- and long, continuum-flow-time-scales, iii) collective hydrodynamic modes known to exist in dense molecular fluids, and iv) short- and long-time-scale velocity autocorrelation functions, central to understanding particle-scale dynamics in strongly interacting, dense fluid systems. The basic system is composed of an imaging system, light source, vibrational sensors, vibrational system with a known media, and PIV and analysis software. Required experimental measurements and an outline of the theoretical tools needed when using the analog technique to study molecular-scale hydrodynamic processes are highlighted. The proposed technique provides a relatively straightforward alternative to photonic and neutron beam scattering methods traditionally used in molecular hydrodynamic studies.

An experimentally accessible analog method for studying molecular hydrodynamic processes in dense fluids is presented. The technique uses particle image velocimetry of vibrated, high-restitution grain piles and allows direct, macroscopic observation of dynamical processes known and predicted to exist in strongly interacting, high density gases and liquids.

一种研究稠密气体和液体分子流体力学过程的模拟宏观技术

An analog, macroscopic method for studying molecular-scale hydrodynamic processes in dense gases and liquids is described. The technique applies a ...

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due to their potential applications for future device technologies such as sensors and storage. However, conventional approaches, which usually utilize materials containing magnetic metal ions (or radicals), have a major problem: only a few materials have been found to show the coupling phenomena at room temperature. Recently, we proposed a new approach to achieve room-temperature magnetoelectrics. In contrast to conventional approaches, our alternative proposal focuses on a completely different material, a &#34;liquid crystal&#34;, free from magnetic metal ions. In such liquid crystals, a magnetic field can be utilized to control the orientational state of constituent molecules and the corresponding electric polarization through magnetic anisotropy of the molecules; it is an unprecedented mechanism of the magnetoelectric effect. In this context, this paper provides a protocol to measure ferroelectric properties induced by a magnetic field, that is, the direct magnetoelectric effect, in a liquid crystal. With the method detailed here, we successfully detected magnetically-tuned electric polarization in the chiral smectic C phase of a liquid crystal at room temperature. Taken together with the flexibility of constituent molecules, which directly affects the magnetoelectric responses, the introduced method will serve to allow liquid crystal cells to acquire more functions as room-temperature magnetoelectrics and associated optical materials.

In this report, we present a protocol to examine direct magnetoelectric effects, i.e., induction of ferroelectric polarization by applying magnetic fields, in liquid crystals. This protocol provides a unique approach, supported by the softness of liquid crystals, to achieve room-temperature magnetoelectrics.

液晶中磁调谐铁电极化的测量

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due ...

In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VOx

Resistive switching crossbar architecture is highly desired in the field of digital memories due to low cost and high-density benefits. Different materials show variability in resistive switching properties due to the intrinsic nature of the material used, leading to discrepancies in the field because of underlying operation mechanisms. This highlights a need for a reliable technique to understand mechanisms using nanostructural observations. This protocol explains a detailed process and methodology of in&#160;situ nanostructural analysis as a result of electrical biasing using transmission electron microscopy (TEM). It provides visual and reliable evidence of underlying nanostructural changes in real time memory operations. Also included is the methodology of fabrication and electrical characterizations for asymmetric crossbar structures incorporating amorphous vanadium oxide. The protocol explained here for vanadium oxide films can be easily extended to any other materials in a metal-dielectric-metal sandwiched structure. Resistive switching crossbars are predicted to serve the programmable logic and neuromorphic circuits for next-generation memory devices, given the understanding of the operation mechanisms. This protocol reveals the switching mechanism in a reliable, timely, and cost-effective way in any type of resistive switching materials, and thereby predicts the device&#39;s applicability.

In Situ Transmission Electron Microscopy with Biasing and Fabrication of Asymmetric Crossbars Based on Mixed-Phased a-VOx

Presented here is a protocol for analyzing nanostructural changes during in&#160;situ biasing with transmission electron microscopy (TEM) for a stacked metal-insulator-metal structure. It has significant applications in resistive switching crossbars for the next generation of programmable logic circuits and neuromimicking hardware, to reveal their underlying operation mechanisms and practical applicability.

基于混合相位a-VOx的不对称横杆的偏置和制造现场传输电子显微镜

Resistive switching crossbar architecture is highly desired in the field of digital memories due to low cost and high-density benefits. Different ...

Performing In Situ Closed-Cell Gas Reactions in the Transmission Electron Microscope

Gas reactions studied by in situ electron microscopy can be used to capture the real-time morphological and microchemical transformations of materials at length scales down to the atomic level. In situ closed-cell gas reaction (CCGR) studies performed using (scanning) transmission electron microscopy (STEM) can separate and identify localized dynamic reactions, which are extremely challenging to capture using other characterization techniques. For these experiments, we used a CCGR holder that utilizes microelectromechanical systems (MEMS)-based heating microchips (hereafter referred to as &#34;E-chips&#34;). The experimental protocol described here details the method for performing in situ gas reactions in dry and wet gases in an aberration-corrected STEM. This method finds relevance in many different materials systems, such as catalysis and high-temperature oxidation of structural materials at atmospheric pressure and in the presence of various gases with or without water vapor. Here, several sample preparation methods are described for various material form factors. During the reaction, mass spectra obtained with a residual gas analyzer (RGA) system with and without water vapor further validates gas exposure conditions during reactions. Integrating an RGA with an in situ CCGR-STEM system can, therefore, provide critical insight to correlate gas composition with the dynamic surface evolution of materials during reactions. In situ/operando studies using this approach allow&#160;for detailed investigation of the fundamental reaction mechanisms and kinetics that occur at specific environmental conditions (time, temperature, gas, pressure), in real-time, and at high spatial resolution.

Performing In Situ Closed-Cell Gas Reactions in the Transmission Electron Microscope

Here, we present a protocol for performing in situ TEM closed-cell gas reaction experiments while detailing several commonly used sample preparation methods.

在传输电子显微镜中执行 原位 闭电池气体反应

Gas reactions studied by in situ electron microscopy can be used to capture the real-time morphological and microchemical transformations of materials at ...