Ultramicroscopy最新文献_第9页

Fourier-based multiple-slice reconstruction in cryo-electron tomography 低温电子断层扫描中基于傅里叶的多层重建

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-11-01 Epub Date: 2025-08-10 DOI: 10.1016/j.ultramic.2025.114223

Ranhao Zhang , Yuan Shen , Xueming Li

A tomogram is reconstructed from the micrographs of the tilt series using cryo-electron tomography (cryoET). Reconstruction frequently integrates image processing steps, such as filtering and contrast transfer function (CTF) correction, to support the downstream analysis of cellular and viral structures. Most image processing steps are based on Fourier space analysis, which is theoretically more efficient to be implemented in Fourier space than in real space. However, the substantial dimensions of tomograms present significant challenges for reconstruction and processing in Fourier space. Consequently, real-space reconstruction is prevalent in current practice. In this study, we proposed a Fourier-space algorithm for tomogram reconstruction, named MUltiple Slice Technique (MUST). MUST considers a tomogram composed of multiple parallel slices, with each slice independently reconstructed in Fourier space. A weighting strategy was used to enable MUST to achieve reconstruction compatible with real-space methods, including weighted back-projection (WBP) and the simultaneous iterative reconstruction technique (SIRT). A three-dimensional CTF model was formulated as pairs of conjugate central paraboloids in Fourier space and subsequently implemented for CTF correction in MUST. Alias-free reconstruction and pixel-level parallel computation are key features of MUST, demonstrated through tomogram-based subtomogram averaging at near-atomic resolutions.

利用低温电子断层扫描（cryoET）从倾斜序列的显微照片重建层析图。重建通常集成图像处理步骤，如滤波和对比度传递函数（CTF）校正，以支持细胞和病毒结构的下游分析。大多数图像处理步骤都是基于傅里叶空间分析，理论上在傅里叶空间中实现比在实际空间中实现更有效。然而，层析图的大尺寸对傅里叶空间的重建和处理提出了重大挑战。因此，在当前的实践中，实空间重构是非常普遍的。在本研究中，我们提出了一种用于层析图重建的傅里叶空间算法，称为多重切片技术（MUltiple Slice Technique， MUST）。MUST考虑由多个平行切片组成的层析图，每个切片在傅里叶空间中独立重建。采用加权策略使MUST能够实现与实空间方法（包括加权反投影（WBP）和同步迭代重建技术（SIRT））兼容的重建。三维CTF模型在傅里叶空间中被表述为一对共轭中心抛物面，随后在MUST中实现CTF校正。无别名重建和像素级并行计算是MUST的关键特征，通过近原子分辨率的基于层析图的子层析图平均来证明。

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引用次数: 0

Impact of electron beam propagation on high-resolution quantitative chemical analysis of 1-nm-wide GaN/AlGaN quantum wells 电子束传播对1纳米宽GaN/AlGaN量子阱高分辨率定量化学分析的影响

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-11-01 Epub Date: 2025-08-19 DOI: 10.1016/j.ultramic.2025.114222

Florian Castioni , Patrick Quéméré , Sergi Cuesta , Vincent Delaye , Pascale Bayle-Guillemaud , Eva Monroy , Eric Robin , Nicolas Bernier

Recent advancements in high-resolution spectroscopy analyses within the scanning transmission electron microscope (STEM) have paved the way for measuring the concentration of chemical species in crystalline materials at the atomic scale. However, several artifacts complicate the direct interpretation of experimental data. For instance, in the case of energy-dispersive X-ray (EDX) spectroscopy, the linear dependency of local X-ray emission on composition is disrupted by channeling effects and cross-talk during electron beam propagation. To address these challenges, it becomes necessary to adopt an approach that combines experimental data with inelastic scattering simulations. This method aims to account for the effects of electron beam propagation on X-ray emission, essentially determining the quantity and the spatial origin of the collected signal. In this publication, we propose to assess the precision and sensitivity limits of this approach in a practical case study involving a focused ion beam (FIB)-prepared III-N multilayers device. The device features nominally pure ∼1.5-nm-wide GaN quantum wells surrounded by AlGaN barriers containing a low concentration of aluminum (∼5 at%). By employing atomic-scale EDX acquisitions based on the averaging of more than several thousand frames, calibrated

ζ

factors combined with a multilayer X-ray absorption correction model for quantification, and by comparing the X-ray radiation obtained from the quantum well with a reference 10-nm-wide structure, we demonstrate that the quantitative impact of beam propagation on chemical composition can be precisely accounted for, resulting in a composition sensitivity at the atomic scale as low as

\pm

0.25 at%. Finally, practical aspects to achieve this high precision level are discussed, particularly in terms of inelastic multislice simulation, uncertainty determination, and sample quality.

扫描透射电子显微镜（STEM）中高分辨率光谱分析的最新进展为在原子尺度上测量晶体材料中化学物质的浓度铺平了道路。然而，一些人为因素使实验数据的直接解释复杂化。例如，在能量色散x射线（EDX）光谱学中，电子束传播过程中的通道效应和串扰破坏了局部x射线发射对成分的线性依赖。为了解决这些挑战，有必要采用一种将实验数据与非弹性散射模拟相结合的方法。该方法旨在解释电子束传播对x射线发射的影响，本质上是确定收集信号的数量和空间来源。在这篇文章中，我们建议在涉及聚焦离子束（FIB）制备的III-N多层器件的实际案例研究中评估该方法的精度和灵敏度限制。该器件具有名义上纯的~ 1.5 nm宽的GaN量子阱，被含有低浓度铝（~ 5 at%）的AlGaN势垒包围。通过采用原子尺度的EDX采集，基于超过几千帧的平均，校准ζ因子结合多层x射线吸收校正模型进行量化，并通过比较从量子阱获得的x射线辐射与参考10纳米宽结构，我们证明了光束传播对化学成分的定量影响可以精确地解释。导致在原子尺度上的成分灵敏度低至±0.25 at%。最后，讨论了实现这种高精度水平的实际方面，特别是在非弹性多片模拟，不确定性确定和样品质量方面。

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引用次数: 0

Breakdown and polarization contrasts in ferroelectric devices observed by operando laser-based photoemission electron microscopy with the AC/DC electrical characterization system 利用交流/直流电学表征系统，利用operando激光光电发射电子显微镜观察铁电器件的击穿和极化对比

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-11-01 Epub Date: 2025-08-11 DOI: 10.1016/j.ultramic.2025.114221

Hirokazu Fujiwara , Yuki Itoya , Masaharu Kobayashi , Cédric Bareille , Toshiyuki Taniuchi

We have developed an operando laser-based photoemission electron microscope (laser-PEEM) with a ferroelectric characterization system. A Sawyer-Tower circuit was implemented to measure the polarization–voltage (P–V) characteristics of ferroelectric devices. Using this system, we successfully obtained the well-defined P–V hysteresis loops for a ferroelectric capacitor incorporating Hf_0.5Zr_0.5O₂ (HZO), reproducing the typical field-cycling characteristics of HZO capacitors. After dielectric breakdown caused by field-cycling stress, we visualized a conduction filament through the top electrode without any destructive processing. Additionally, we successfully observed polarization contrast through the top electrode of an oxide semiconductor (InZnO_x). These results indicate that our operando laser-PEEM system is a powerful tool for visualizing conduction filaments after dielectric breakdown, the ferroelectric polarization contrasts, and electronic state distribution of materials implemented in ferroelectric devices, including ferroelectric field-effect transistors and ferroelectric tunnel junctions.

我们开发了一种具有铁电表征系统的基于operando激光的光电电子显微镜（laser-PEEM）。采用索耶-塔式电路测量铁电器件的极化电压特性。利用该系统，我们成功地获得了含有HZO （Hf0.5Zr0.5O2）的铁电电容器的P-V磁滞回线，再现了HZO电容器的典型场循环特性。在场循环应力引起的介质击穿后，我们在没有任何破坏性处理的情况下，通过顶部电极看到了导电丝。此外，我们成功地通过氧化物半导体（InZnOx）的顶电极观察到极化对比。这些结果表明，我们的operando激光- peem系统是一个强大的工具，用于可视化介电击穿后的导电丝，铁电极化对比和铁电器件中材料的电子态分布，包括铁电场效应晶体管和铁电隧道结。

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引用次数: 0

Improving the low-dose performance of aberration correction in single sideband ptychography 提高单边带成像像差校正的低剂量性能

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-11-01 Epub Date: 2025-08-23 DOI: 10.1016/j.ultramic.2025.114225

Songge Li , Nicolas Gauquelin , Hoelen L. Lalandec Robert , Arno Annys , Chuang Gao , Christoph Hofer , Timothy J. Pennycook , Jo Verbeeck

The single sideband (SSB) framework of analytical electron ptychography can account for the presence of residual geometrical aberrations induced by the probe-forming lens. However, the accuracy of this aberration correction method is highly sensitive to the invested electron dose, in part due to the necessity of phase unwrapping. In this work, we thus propose two strategies to improve the performance in low-dose conditions: confining phase unwrapping within the sidebands and selecting only well-unwrapped sidebands for calculating aberration coefficients. These strategies are validated through SSB reconstructions of both simulated and experimental 4D-STEM datasets of monolayer tungsten diselenide (WSe₂). A comparison of results demonstrates significant improvements in Poisson noise tolerance, making aberration correction more robust and reliable for low-dose imaging.

分析电子平面摄影的单边带（SSB）框架可以解释探针形成透镜引起的残余几何像差的存在。然而，这种像差校正方法的精度对所投入的电子剂量高度敏感，部分原因是相位展开的必要性。在这项工作中，我们因此提出了两种策略来提高在低剂量条件下的性能：在侧带内限制相位展开和只选择充分展开的侧带来计算像差系数。通过单层二硒化钨（WSe2）的模拟和实验4D-STEM数据集的SSB重建，验证了这些策略。对比结果表明，泊松噪声耐受性显著提高，使像差校正在低剂量成像中更加稳健和可靠。

引用次数: 0

Resonant scattering in low energy electron diffraction: Bi/Ni(111) 低能电子衍射中的共振散射：Bi/Ni（111）

IF 2 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-11-01 Epub Date: 2025-07-28 DOI: 10.1016/j.ultramic.2025.114220

Bene Poelsema, Martina Tsvetanova, Harold J.W. Zandvliet, Arie van Houselt

We report Low Energy Electron Diffraction (LEED) diffraction patterns measured at energies up to 50 eV for a monolayer thick Bi film on Ni(111). Surprisingly, the intensity versus energy profiles of several from the ten unique (i.e., symmetry-independent) sets of spots show finite but pertinent intensity, each only at a well-defined energy. These are attributed to resonant scattering, involving transient capture in eigenstates of the image potential, followed by (multiple) scattering into the vacuum. By its nature, transient capture occurs closely before the energy crosses the Ewald sphere for each considered channel. These energies are one-to-one connected with the corresponding lattice parameters of the Bi-film with its centered rectangular structure, commensurate along Ni[11–2] and high order commensurate along Ni[-110].

In addition, a couple of more intense regular spots show anomalously high intensity at the low energy side upon crossing the Ewald sphere. This feature is attributed to resonant scattering as well. We claim that so far grossly disregarded resonant scattering is a general phenomenon and should be considered in very low energy LEED-IV structural analysis.

The intensity versus energy profile of the (0 2) peak does not show obvious evidence for resonant scattering but instead reveals that the Bi film is built up by long (> 20 nm) and narrow (<< 20 nm), translationally shifted domains, oriented along the [-110] azimuth.

我们报道了Ni（111）上单层厚Bi薄膜在能量高达50 eV时的低能电子衍射（LEED）衍射图。令人惊讶的是，十个独特的（即，对称无关的）光斑集合中的几个的强度与能量分布显示有限但相关的强度，每个只在一个定义良好的能量。这些都归因于共振散射，涉及图像势的本征态的瞬态捕获，随后（多次）散射到真空中。就其性质而言，瞬态捕获发生在能量穿过每个通道的埃瓦尔德球之前。这些能量与具有中心矩形结构的双膜相应的晶格参数呈一一对应关系，沿Ni[11-2]成正比，沿Ni[-110]成高阶成正比。此外，一对更强烈的规则斑点在穿过埃瓦尔德球时，在低能侧表现出异常的高强度。这一特点也归因于共振散射。我们认为，到目前为止，被严重忽视的共振散射是一种普遍现象，应该在极低能量的LEED-IV结构分析中加以考虑。（02）峰的强度-能量分布图没有显示出明显的共振散射证据，而是表明Bi膜是由长(>；20 nm)和窄(<<；20 nm)，平移位移域，沿[-110]方位角取向。

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引用次数: 0

Can low energy (1–20 eV) electron microscopy produce damage-free images of biological samples? 低能量（1-20 eV）电子显微镜能产生无损伤的生物样品图像吗？

IF 2.1 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-10-01 Epub Date: 2025-06-16 DOI: 10.1016/j.ultramic.2025.114197

Yi Zheng, Léon Sanche

Electron microscopy constitutes an efficient and well-established method to visualize biological material on the nanoscale. The image is usually produced by a high energy electron beam, which can damage the biological sample. To reduce image degradation, Neu et al. [Ultramicroscopy 222 (2021) 113,199] recently suggested the possibility of damage-free imaging of such samples at nm resolution using as a probe low energy electron (LEEs). The aims of the present article are to 1) present a simple and short description of LEE inelastic scattering and attachment in molecular solids in the 0–20 eV range, 2) show that principally due to the formation of transient anions (TAs) in biological material, by temporary LEE attachment to molecular sites, damage-free electron microscopy may be difficult to achieve and 3) suggest specimen conditions that reduce the damage produced by TAs to inflict minimum damage to biological samples in LEE microscopy. We provide examples of lesions induced by electrons of energies below 3 eV in short DNA strands composed of 16 base-pair oligonucleotides and on the 1–20 eV dependence of effective damage yields from LEE-bombarded plasmid DNA. The damaged samples were produced from 5-monolayer films lyophilized on tantalum substrates and transferred to ultra-high vacuum to be bombarded with LEEs. The products were identified and quantified ex-vacuo by LC-MS-MS and electrophoresis, respectively. Such effective yields, and the corresponding absolute cross sections derived from model analysis, should allow estimating beam damage and image quality in the visualization of thin biological films by LEE microscopy.

电子显微镜是一种在纳米尺度上观察生物材料的有效且成熟的方法。图像通常是由高能电子束产生的，这可能会破坏生物样品。为了减少图像退化，Neu等人[超微显微镜222(2021)113,199]最近提出了在纳米分辨率下使用低能量电子（LEEs）作为探针对这些样品进行无损伤成像的可能性。本文的目的是：1)在0-20 eV范围内对分子固体中LEE的非弹性散射和附着进行简单而简短的描述；2)表明，主要由于生物材料中瞬态阴离子（TAs）的形成，通过LEE对分子位点的临时附着，无损伤电子显微镜可能难以实现，并且3)建议在LEE显微镜中减少TAs产生的损伤以对生物样品造成最小损伤的样品条件。我们提供了能量低于3 eV的电子在由16个碱基对寡核苷酸组成的短DNA链中引起损伤的例子，以及1-20 eV依赖于lee轰击质粒DNA的有效损伤产量。损坏的样品是由在钽衬底上冻干的5层单层薄膜制成的，然后转移到超高真空中用LEEs轰击。分别用LC-MS-MS和电泳对产物进行鉴定和定量。这样的有效产率，以及从模型分析中得出的相应的绝对横截面，应该可以通过LEE显微镜来估计生物薄膜可视化中的光束损伤和图像质量。

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引用次数: 0

Differences between differential phase contrast and electron holographic measurements of a GaN p-n junction GaN p-n结差相衬和电子全息测量的差异

IF 2.1 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-10-01 Epub Date: 2025-06-21 DOI: 10.1016/j.ultramic.2025.114191

Laura Niermann

Modern semiconductor devices require control of the electrostatic potential landscape at nanometer scale, which is especially important for materials like the Group III-Nitrides, where polarization effects cause additional sheet charges at interfaces. In this work two complementary electron microscopic methods, differential phase contrast (DPC) and electron holography (EH), are used for characterization of a GaN p–n junction in one and the same sample. In comparison, the values obtained for the junction’s characteristics, like the built-in potential step, the maximum fields strength, and the width of the space charge region, were significantly larger and also closer to the expected values, when measured by means of EH. A key difference in the measurements is the vastly lower illumination dose rates within the EH experiments. Therefore, the lower generation rate of electron–hole pairs might lead to a lower beam induced bias during the EH measurement. These findings demonstrate that in future experiments the impact of the electron illumination must be considered for accurate nanoscale electrostatic field and potential measurements.

现代半导体器件需要在纳米尺度上控制静电势，这对于像iii族氮化物这样的材料尤其重要，因为极化效应会在界面处引起额外的片电荷。在这项工作中，两种互补的电子显微镜方法，差分相对比（DPC）和电子全息（EH），用于表征一个GaN p-n结在一个和相同的样品。相比之下，用EH测量时得到的结的特性值，如内置电位阶跃、最大场强和空间电荷区宽度，都明显更大，也更接近期望值。测量中的一个关键区别是EH实验中的照明剂量率要低得多。因此，较低的电子-空穴对产生率可能导致在EH测量过程中较低的光束诱导偏置。这些发现表明，在未来的实验中，电子照明的影响必须考虑到精确的纳米级静电场和电位测量。

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引用次数: 0

TEM-EDS microanalysis: Comparison between different electron sources, accelerating voltages and detection systems TEM-EDS微分析：不同电子源、加速电压和检测系统的比较

IF 2.1 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-10-01 Epub Date: 2025-06-17 DOI: 10.1016/j.ultramic.2025.114201

Roberto Conconi , María del Mar Abad Ortega , Fernando Nieto , Paolo Buono , Giancarlo Capitani

Two TEM-EDS quantification methods based on standards of known compositions, namely the Cliff and Lorimer approximation and the absorption correction method based on electroneutrality are employed and the results obtained with three different TEMs and EDS systems, compared. The three TEM instruments differ in source type (field emission vs. thermionic), accelerating voltage (200 vs. 300 kV) and EDS system type (4 in-column silicon drift detector (SDD) vs. single SDD). We found that EDS calibration appears to be “strictly instrument specific”, i.e., no universally valid k-factors can exist, but only k-factor sets for a specific combination of microscope and EDS system. As expected, 4-in column SDD systems, because of their larger sensitive areas compared to classical single SDD, are more efficient in data collection and, therefore, have lower detection limits. However, other sources of error may influence the final output, sometimes subverting the expectations. EDS analyses performed with FEG-TEMs exhibit lower radiation-induced migration of weakly bounded elements than TEMs equipped with a conventional source and lower beam current. This result may be explained by the smaller spot size used with the conventional TEM that in total led to a higher electron dose per sample atom. In addition, this work confirms that the absorption correction method is to be preferred whenever dealing with thick and/or dense samples, whereas the Cliff and Lorimer approximation, because simpler and faster, in all the other cases. Finally, we renew the necessity to determine two distinct k_O/Si factors, one for lighter and one for denser compounds.

采用Cliff和Lorimer近似法和基于电中性的吸收校正法两种基于已知组分标准的TEM-EDS定量方法，并比较了三种不同tem和EDS体系的结果。这三种TEM仪器在源类型（场发射vs热离子）、加速电压（200 vs 300 kV）和EDS系统类型（4列硅漂移检测器（SDD） vs单列SDD）上有所不同。我们发现EDS校准似乎是“严格特定于仪器”，即不存在普遍有效的k因子，而只有特定显微镜和EDS系统组合的k因子集。正如预期的那样，4-in柱SDD系统，由于与传统的单SDD相比具有更大的敏感区域，因此在数据收集方面更有效，因此具有更低的检测限。但是，其他错误来源可能会影响最终输出，有时会破坏预期。用feg - tem进行的EDS分析显示，弱边界元素的辐射诱导迁移比配备常规源和较低光束电流的tem低。这一结果可以解释为使用传统TEM的光斑尺寸较小，总的来说导致每个样品原子的电子剂量较高。此外，这项工作证实了吸收校正方法在处理厚和/或致密样品时是首选的，而Cliff和Lorimer近似在所有其他情况下都更简单，更快。最后，我们重申有必要确定两个不同的kO/Si因子，一个用于较轻的化合物，一个用于较致密的化合物。

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引用次数: 0

Data-efficient 4D-STEM in SEM: Beyond 2D materials to metallic materials 扫描电镜中数据高效的4D-STEM：从二维材料到金属材料

IF 2.1 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-10-01 Epub Date: 2025-07-01 DOI: 10.1016/j.ultramic.2025.114203

Ujjval Bansal , Amit Sharma , Barbara Putz , Christoph Kirchlechner , Subin Lee

Four-dimensional scanning transmission electron microscopy (4D-STEM) is a powerful tool that allows for the simultaneous acquisition of spatial and diffraction information, driven by recent advancements in direct electron detector technology. Although 4D-STEM has been predominantly developed for and used in conventional TEM and STEM, efforts are being made to implement the technique in scanning electron microscopy (SEM). In this paper, we push the boundaries of 4D-STEM in SEM and extend its capabilities in three key aspects: (1) faster acquisition rate with reduced data size, (2) higher angular resolution, and (3) application to various materials including conventional alloys and focused ion beam (FIB) lamella. Specifically, operating the MiniPIX Timepix3 detector in the event-driven mode significantly improves the acquisition rate by a factor of a few tenths compared to conventional frame-based mode, thereby opening up possibilities for integrating 4D-STEM into various in situ SEM testing. Furthermore, with a novel stage-detector geometry, a camera length of 160 mm is achieved which improves the angular resolution amplifying its utility, for example, magnetic or electric field imaging. Lastly, we successfully imaged a nanostructured platinum-copper thin film with a grain size of 16 nm and a thickness of 20 nm, and identified annealing twins in FIB-prepared polycrystalline copper using virtual dark-field imaging and orientation mapping. This work demonstrates the potential of synergetic combination of 4D-STEM with in situ experiments, and broadening its applications across a wide range of materials.

四维扫描透射电子显微镜（4D-STEM）是一个强大的工具，允许同时获取空间和衍射信息，由直接电子探测器技术的最新进展驱动。尽管4D-STEM主要是为传统的TEM和STEM开发和使用的，但人们正在努力将该技术应用于扫描电子显微镜（SEM）。在本文中，我们推动了4D-STEM在SEM中的边界，并在三个关键方面扩展了其能力：(1)更快的采集速度和更小的数据大小，(2)更高的角分辨率，以及(3)应用于各种材料，包括传统合金和聚焦离子束（FIB）片层。具体来说，在事件驱动模式下操作MiniPIX Timepix3探测器，与传统的基于帧的模式相比，采集率显著提高了几十倍，从而为将4D-STEM集成到各种原位SEM测试中提供了可能性。此外，采用新颖的舞台探测器几何结构，实现了160毫米的相机长度，提高了角度分辨率，放大了其实用性，例如磁场或电场成像。最后，我们成功地对晶粒尺寸为16 nm，厚度为20 nm的纳米结构铂铜薄膜进行了成像，并利用虚拟暗场成像和取向映射识别了fib制备的多晶铜中的退火孪晶。这项工作证明了4D-STEM与原位实验协同结合的潜力，并扩大了其在广泛材料中的应用。

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引用次数: 0

Development of an image-forming system for the magnetic field-free electron microscope 无磁场电子显微镜成像系统的研制

IF 2.1 3区工程技术 Q2 MICROSCOPY

Ultramicroscopy

Pub Date : 2025-10-01 Epub Date: 2025-06-01 DOI: 10.1016/j.ultramic.2025.114181

T. Maekawa , Y. Kohno , A. Yasuhara , S. Morishita , T. Inoue , Y. Ueda , K. Arakawa

The successful development of a magnetic field-free objective lens for high-resolution imaging has enabled the acquisition of atomic-resolution scanning transmission electron microscopy (STEM) images under magnetic field-free conditions around the sample. Utilizing this magnetic field-free objective lens for conventional transmission electron microscopy (TEM) observations is expected to offer advantages for the comprehensive characterization of magnetic materials. This approach is particularly significant in the context of in-situ observations. To obtain conventional TEM images, such as bright- and dark-field images, it is important to position the objective lens aperture in a diffraction plane, typically the back focal plane of the objective lens. However, positioning the objective lens aperture around the back focal plane, which is surrounded by multiple magnetic poles, is not feasible for the magnetic field-free objective lens. In this study, we describe the development of an image-forming system that can position the aperture in a diffraction plane conjugate to the back focal plane. In addition, the development of a wide-gap pole piece for the magnetic field-free objective lens has enabled the use of sample holders with thick tips for in-situ observations. The magnetic field-free electron microscope, which integrates a newly developed pole piece and image-forming system with higher-order aberration correctors, offers not only atomic-resolution TEM/STEM observations but also a versatile approach for the characterization of magnetic materials in a magnetic field-free environment.

用于高分辨率成像的无磁场物镜的成功开发使得在样品周围无磁场条件下获得原子分辨率扫描透射电子显微镜（STEM）图像成为可能。利用这种无磁场物镜进行常规透射电子显微镜（TEM）观察有望为磁性材料的全面表征提供优势。这种方法在现场观测中特别重要。为了获得常规的TEM图像，如明暗场图像，重要的是将物镜孔径定位在衍射平面上，通常是物镜的后焦平面。然而，对于无磁场物镜，将物镜孔径定位在被多个磁极包围的后焦平面周围是不可行的。在本研究中，我们描述了一种成像系统的发展，该系统可以将孔径定位在与后焦平面共轭的衍射平面上。此外，用于无磁场物镜的宽间隙极片的开发使得使用具有厚尖端的样品支架进行原位观测成为可能。无磁场电子显微镜集成了新开发的极片和图像形成系统以及高阶像差校正器，不仅提供原子分辨率的TEM/STEM观测，而且还提供了在无磁场环境中表征磁性材料的通用方法。

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引用次数: 0