scholarly journals Atomic Resolution Electron Microscopy: A Key Tool for Understanding the Activity of Nano-Oxides for Biomedical Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2073
Author(s):  
Alberto Azor-Lafarga ◽  
Isabel Gómez-Recio ◽  
M. Luisa Ruiz-González ◽  
José M. González-Calbet
Keyword(s):  
Electron Microscopy ◽  
Transition Metal ◽  
Oxidation State ◽  
Transition Metal Oxides ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Atomic Resolution ◽  
Local Composition ◽  
Resolution Electron ◽  
Potential Applications

Transition metal oxides constitute one of the most fruitful sources of materials with continuously increasing potential applications prompted by the expectations derived from the reduction of the particle size. The recent advances in transmission electron microscopy, because of the development of lenses, have made it possible to reach atomic resolution, which can provide answers regarding the performance of the transition metal nano-oxides. This critical information is related not only to the ability to study their microstructural characteristics but also their local composition and the oxidation state of the transition metal. Exploring these features is a well-known task in nano-oxides for energy and electronic technologies, but they are not so commonly used for elucidating the activity of these oxides for biomedical applications. Nevertheless, the identification at the atomic level of a certain dopant or the unambiguous determination of the oxidation state of a transition metal in a nano-oxide can be important questions to be answered in a certain biomedical application. In this work, we provide several examples in transition metal nano-oxides to show how atomic-resolution electron microscopy can be a key tool for its understanding.

Fabrication and characterization - by High Resolution Electron Microscopy and atom probe microanalysis - of Co-based metallic multilayer films

1990 ◽  
Vol 48 (4) ◽  
pp. 772-773
Author(s):  
Amanda K. Petford-Long ◽  
A. Cerezo ◽  
M.G. Hetherington
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Atom Probe ◽  
Multilayer Films ◽  
Interface Roughness ◽  
Probe Field ◽  
Resolution Electron ◽  
Potential Applications ◽  
Field Ion Microscope

The fabrication of multilayer films (MLF) with layer thicknesses down to one monolayer has led to the development of materials with unique properties not found in bulk materials. The properties of interest depend critically on the structure and composition of the films, with the interfacial regions between the layers being of particular importance. There are a number of magnetic MLF systems based on Co, several of which have potential applications as perpendicular magnetic (e.g Co/Cr) or magneto-optic (e.g. Co/Pt) recording media. Of particular concern are the effects of parameters such as crystallographic texture and interface roughness, which are determined by the fabrication conditions, on magnetic properties and structure.In this study we have fabricated Co-based MLF by UHV thermal evaporation in the prechamber of an atom probe field-ion microscope (AP). The multilayers were deposited simultaneously onto cobalt field-ion specimens (for AP and position-sensitive atom probe (POSAP) microanalysis without exposure to atmosphere) and onto the flat (001) surface of oxidised silicon wafers (for subsequent study in cross-section using high-resolution electron microscopy (HREM) in a JEOL 4000EX. Deposi-tion was from W filaments loaded with material in the form of wire (Co, Fe, Ni, Pt and Au) or flakes (Cr). The base pressure in the chamber was around 8×10−8 torr during deposition with a typical deposition rate of 0.05 - 0.2nm/s.

scholarly journals Femtosecond M2,3-Edge Spectroscopy of Transition-Metal Oxides: Photoinduced Oxidation State Change in α-Fe2O3

2013 ◽  
Vol 4 (21) ◽  
pp. 3667-3671 ◽  
Author(s):  
Josh Vura-Weis ◽  
Chang-Ming Jiang ◽  
Chong Liu ◽  
Hanwei Gao ◽  
J. Matthew Lucas ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Oxidation State ◽  
Transition Metal Oxides ◽  
State Change

Valence Mapping of Particulate 3D-Transition Metal Oxides Using Energyfiltered Transmission Electron Microscopy

2000 ◽  
Vol 6 (S2) ◽  
pp. 176-177
Author(s):  
R.M. Stroud ◽  
J.H. Scott
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Data Extraction ◽  
Mixed Valence ◽  
Charge Localization ◽  
Transmission Electron ◽  
Critical Issues

Particulate, mixed-valence transition metal oxides are frequently used for battery, catalytic and magnetic applications. For example, the Li ion exchange battery exploits charge transfer of mixed Mn+3, Mn+4 materials. Charge localization and phase separation, especially at particle surfaces, are critical issues for determining the materials’ useful properties, be it catalytic activity or saturation magnetization. The ability to image the charge localization and correlate this with crystallographic information would be extremely useful in the study of this class of materials. Using energy-filtered transmission electron microscopy (EFTEM), valence maps of Mn and Co with a ∼ 2 nm scale have been obtained for bulk samples. In principal this technique can de directly extended to the case of particulate samples, however there are some additional experimental challenges, such as thickness and edge effects, that must be addressed. We demonstrate here the feasibility of valence mapping of particulate samples, and discuss the factors that limit quantitative data extraction from the maps.

scholarly journals Atomic-resolution electron microscopy of nanoscale local structure in lead-based relaxor ferroelectrics

2020 ◽  
Vol 20 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Abinash Kumar ◽  
Jonathon N. Baker ◽  
Preston C. Bowes ◽  
Matthew J. Cabral ◽  
Shujun Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Local Structure ◽  
Relaxor Ferroelectrics ◽  
Atomic Resolution ◽  
Resolution Electron

Atomically Thin 2D Transition Metal Oxides: Structural Reconstruction, Interaction with Substrates, and Potential Applications

2018 ◽  
Vol 6 (1) ◽  
pp. 1801160 ◽  
Author(s):  
Tong Yang ◽  
Ting Ting Song ◽  
Martin Callsen ◽  
Jun Zhou ◽  
Jian Wei Chai ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Potential Applications
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