Transmission electron microscopy studies of the effect of A-site cation size mismatch and disorder on charge ordering behavior in (La1−xYx)0.5(Ca1−ySry)0.5MnO3

2001 ◽  
Vol 78 (15) ◽  
pp. 2157-2159 ◽  
Author(s):  
Y. Q. Wang ◽  
X. F. Duan ◽  
Z. H. Wang ◽  
B. G. Shen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Charge Ordering ◽  
Size Mismatch ◽  
Transmission Electron ◽  
A Site ◽  
Cation Size

scholarly journals Structural and Electrical Properties of Ca2+ Doped LaFeO3: The Effect of A-site Cation Size Mismatch

2020 ◽  
Vol 10 (2) ◽  
pp. 5538-5546
Author(s):  
A. E. Irmak
Keyword(s):  
Crystal Structure ◽  
Sol Gel ◽  
Charge Ordering ◽  
Room Temperature Resistivity ◽  
Size Mismatch ◽  
Ca Doping ◽  
Average Size ◽  
A Site ◽  
Cation Size ◽  
Small Polarons

In this study, nanosized La1-xCaxFeO3 (0.00≤x≤0.40) compounds prepared via sol-gel method followed by heat treatment at 1100oC for 24 hours are studied. Crystal structure, microstructure, surface morphology and temperature-dependent resistivity of the samples are investigated. TEM investigation reveals nanoparticles with an average size of 35nm produced from the sol-gel process. The crystal structure of the compounds belongs to an orthorhombically distorted perovskite structure with Pbnm space group. Lattice distortion and cation size mismatch increase with an increase in Ca and particle and grain growth are suppressed by Ca doping. Electrical conduction is explained via thermally activated hopping of small polarons. Unit cell volume, charge ordering temperature, and activation energy for small polarons decrease linearly with an increase in cation size mismatch. Room temperature resistivity decreases with Ca doping and gets its minimum value for 30% Ca at which the orthorhombic distortion is maximum.

Scanning transmission electron microscopy of nanostructures

2017 ◽  
Author(s):  
S.J. Pennycook ◽  
M. Varela ◽  
M.F. Chisholm ◽  
A.Y. Borisevich ◽  
A.R. Lupini ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Quantum Wires ◽  
Semiconductor Nanocrystals ◽  
Charge Ordering ◽  
Spatial Average ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

This article investigates nanostructures by means of scanning transmission electron microscopy. The electron microscope is uniquely suited to the study of individual nanostructures, allowing differentiation of different structures and properties that is difficult or impossible to do with techniques that provide a spatial average. The present generation of aberration correctors, which correct all aberrations up to third order, makes it possible to obtain sufficient sensitivity to image and spectroscopically analyze single atoms. This article begins with a brief overview of the correction of lens aberration in electron microscopy, followed by several examples of insights into nanomaterials and the atomic origins of their functionality. In particular, it considers semiconductor nanocrystals, semiconductor quantum wires, and nanocatalysts. It also discusses magnetism in gold and silver nanoclusters as well as charge ordering in manganites.

Chemical Composition, Geochemical Alteration, and Radiation Damage Effects in Natural Perovskite

1997 ◽  
Vol 506 ◽  
Author(s):  
Gregory R. Lumpkin ◽  
Michael Colella ◽  
Katherine L. Smith ◽  
Roger H. Mitchell ◽  
Alf Olav Larsen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
Electron Diffraction ◽  
Perovskite Structure ◽  
Alpha Decay ◽  
Primary Result ◽  
Transmission Electron ◽  
A Site ◽  
Dose Levels

ABSTRACTPreliminary analytical and transmission electron microscopy (AEM and TEM) results for a small suite of natural perovskites are reported in this paper and discussed in relation to previous work. We show that perovskite compositions in Synroc and tailored ceramics plot within the known fields of natural perovskite compositions. AEM analyses and electron diffraction work on selected samples indicate that they are predominantly stoichiometric variants of the cubic perovskite structure. Geochemical alteration was observed in one sample of loparite from Bratthagen, Norway. The primary result of this alteration was leaching of Na from the A-site. Although sufficient alpha-decay dose levels for complete amorphization are not realized in this suite of samples, the available data bracket the beginning of the crystalline-amorphous transformation at doses that are ∼ 2-4 times greater than those of zirconolite of similar age. These results may be due to fundamental differences in the damage annealing rates of perovskite and zirconolite.

A site-specific focused-ion-beam lift-out method for cryo Transmission Electron Microscopy

2012 ◽  
Vol 180 (3) ◽  
pp. 572-576 ◽  
Author(s):  
Stefano Rubino ◽  
Sultan Akhtar ◽  
Petter Melin ◽  
Andrew Searle ◽  
Paul Spellward ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Site Specific ◽  
Transmission Electron ◽  
A Site

Effect of A-site cation size mismatch on charge ordering behavior in (La1−xYx)0.5(Ca1−ySry)0.5MnO3

2001 ◽  
Vol 90 (1) ◽  
pp. 488-492 ◽  
Author(s):  
Y. Q. Wang ◽  
Ian Maclaren ◽  
X. F. Duan ◽  
Z. H. Wang ◽  
B. G. Shen
Keyword(s):  
Charge Ordering ◽  
Size Mismatch ◽  
A Site ◽  
Cation Size

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

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