We demonstrate local crystal structure analysis based on annular dark-field (ADF) imaging in scanning transmission electron microscopy (STEM). Using a stabilized STEM instrument and customized software, we first realize high accuracy of elemental discrimination and atom-position determination with a 10-pm-order accuracy, which can reveal major cation displacements associated with a variety of material properties, e.g. ferroelectricity and colossal magnetoresistivity. A-site ordered/disordered perovskite manganites Tb(0.5)Ba(0.5)MnO(3) are analysed; A-site ordering and a Mn-site displacement of 12 pm are detected in each specific atomic column. This method can be applied to practical and advanced materials, e.g. strongly correlated electron materials.
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http://dx.doi.org/10.1093/jmicro/dfn023 | DOI Listing |
Nanomaterials (Basel)
December 2024
Emerging Technologies Research Center, XPANCEO, Internet City, Emmay Tower, Dubai, United Arab Emirates.
Due to their high refractive index, record optical anisotropy and a set of excitonic transitions in visible range at a room temperature, transition metal dichalcogenides have gained much attention. Here, we adapted a femtosecond laser ablation for the synthesis of WSe nanoparticles (NPs) with diameters from 5 to 150 nm, which conserve the crystalline structure of the original bulk crystal. This method was chosen due to its inherently substrate-additive-free nature and a high output level.
View Article and Find Full Text PDFSmall
January 2025
Key Laboratory of Multiscale Spin Physics, Ministry of Education, School of Physics and Astronomy, Beijing Normal University, Beijing, 100875, P. R. China.
The etch-engineering is a feasible avenue to tailor the layer number and morphology of 2D layered materials during the chemical vapor deposition (CVD) growth. However, less reports strengthen the etch-engineering used in the fabrication of high-quality transition metal dichalcogenide (TMD) materials with tunable layers and desirable morphologies to improve their prominent performance in electronic and optoelectronic devices. Here, an etching-and-growth coexistence method is reported to directly synthesize high-quality, high-symmetric MoS bilayers with versatile morphologies via CVD.
View Article and Find Full Text PDFSmall
January 2025
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing WUT Nano Key Lab, Wuhan, Hubei, 430070, China.
The irreversible lattice oxygen release is the primary issue in layered oxide cathodes which is generally attributed to a consecutive phase transition with less lattice oxygen content. Herein, an anomalous metal segregation pathway is observed in oxygen vacancy defective layered cathodes, which happens far before the onset of phase transitions. The correlation of electron energy loss spectroscopy indicates that an early charge transfer from oxygen 2p to Mn 3d orbital is responsible.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Institut de Recherche sur les Céramiques (IRCER), UMR CNRS 7315-Université de Limoges, France.
A semi-automated workflow relying on atomic-scale modelling is introduced to explore and understand the yet-unsolved structure of the crystalline AsTe material, recently obtained from crystallization of the parent AsTe glass, which shows promising properties for thermoelectric applications. The seemingly complex crystal structure of AsTe is investigated with density functional theory, from the stand point of As/Te disorder, in a structural template derived from elemental-Te (Te), following experimental findings from combined X-ray total scattering and diffraction. Our workflow includes a combinatorial structure generation step followed by successive structure selection and relaxation steps with progressively-increasing accuracy levels and a multi-criterion evaluation procedure.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
Searching for single-molecule magnets (SMM) with large effective blocking barriers, long relaxation times, and high magnetic blocking temperatures is vitally important not only for the fundamental research of magnetism at the molecular level but also for the realization of new-generation magnetic memory unit. Actinides (An) atoms possess extremely strong spin-orbit coupling (SOC) due to their 5 orbitals, and their ground multiplets are largely split into several sublevels because of the strong interplay between the SOC of An atoms and the crystal field (CF) formed by ligand atoms. Compared to TM-based SMMs, more dispersed energy level widths of An-based SMMs will give a larger total zero field splitting (ZFS) and thus provide a necessary condition to derive a higher .
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