Observation of vortex domain structures in multiferroic hexagonal manganites RMnO3by transmission electron microscopy

Microscopy ◽  
2014 ◽  
Vol 63 (suppl 1) ◽  
pp. i22.3-i22
Author(s):  
Yoichi Horibe ◽  
Fei-Ting Huang ◽  
Taekjib Choi ◽  
Nara Lee ◽  
Sang-Wook Cheong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Domain Structures ◽  
Transmission Electron ◽  
Hexagonal Manganites

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The Crystal Structure of the β’-Phase Including Ag in Al-Mg-Si-Ag Alloy

2011 ◽  
Vol 409 ◽  
pp. 67-70 ◽  
Author(s):  
Junya Nakamura ◽  
Kenji Matsuda ◽  
Tatsuo Sato ◽  
Calin D. Marioara ◽  
Sigmund J. Andersen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dark Field ◽  
Unit Cell ◽  
Atomic Column ◽  
Direction Parallel ◽  
Ag Addition ◽  
Domain Structures ◽  
Β Phase ◽  
Transmission Electron

In the present work, b’ phase in alloys Al -1.0 mass% Mg2Si -0.5 mass% Ag (Ag-addition) and Al -1.0 mass% Mg2Si (base) was investigated by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) to understand the effect of Ag addition. The b’ phase is rod-shape with the longest direction parallel to <001>Al. HRTEM images and SAED patterns obtained along the direction were similar for the b’ phase in both alloys. The unit cell of b’-phase in Ag-addition alloy is hexagonal with the same c-axis dimension as the Ag-free b’, but shorter a-axis. Ag was found in the composition of the rod-shaped precipitates in Ag-addition alloy by energy dispersive X-ray spectroscopy (EDS). In addition, the distribution of Ag was investigated by energy filtered mapping and high annular angular dark field scanning transmission electron microscopy (HAADF-STEM). The Ag-containing atomic column was observed in every b’ unit cell, and the unit cell symmetry is slightly changed as compared with the Ag-free b’. The Ag-containing b’ rods have complicated domain structures. The interfaces of these particles are enriched with Ag atoms that occupy the lattice positions in the Al matrix. The occupancy of the Ag-containing atomic columns seem to vary both inside particles, as well as at the interfaces.

In-Situ Transmission Electron Microscopy and Computer Simulation Study of the Kinetics of Oxygen Loss in Yba2Cu3OZ

1989 ◽  
Vol 169 ◽  
Author(s):  
C. P. Burmester ◽  
L. T. Wille ◽  
R. Gronsky ◽  
B. T. Ahn ◽  
V. Y. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulation Study ◽  
Oxygen Loss ◽  
Domain Structures ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Image Simulations

AbstractHigh resolution transmission electron microscopy during in‐situ quenching of YBa2Cu3Oz is used to study the kinetics of microdomain formation during oxygen loss in this system. Image simulations based on atomic models of oxygen‐vacancy order in the basal plane of this material generated by Monte Carlo calculations are used to interpret high resolution micrographs of the structures obtained by quenching. The observed domain structures agree well with those obtained from the simualtions.

Transmission electron microscopy study of domain structures in ferroelectric SrBi2Nb2O9 ceramics

2004 ◽  
Vol 839 ◽  
Author(s):  
C. Karthik ◽  
N. Ravishankar ◽  
K.B.R. Varma
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Ferroelectric Ceramics ◽  
Potential Candidate ◽  
Transmission Electron Microscopy Study ◽  
Antiphase Boundaries ◽  
Domain Structures ◽  
Transmission Electron

ABSTRACTA transmission electron microscopy study has been carried out on the domain structures of SrBi2Nb2O9 (SBN) ferroelectric ceramics which belong to the Aurivillius family of bismuth layered perovskite oxides. SBN is a potential candidate for Ferroelectric Random access memory (FeRAM) applications. The 90° ferroelectric domains and antiphase boundaries (APBs) were identified with dark field imaging techniques using different superlattice reflections which arise as a consequence of octahedral rotations and cationic shifts. The 90° domain walls are irregular in shape without any faceting. The antiphase boundaries are less dense compared to that of SrBi2Ta2O9(SBT). The electron microscopy observations are correlated with the polarization fatigue nature of the ceramic where the domain structures possibly play a key role in the fatigue- free behavior of the Aurivillius family of ferroelectric oxides.

Ferroelectric Domain Structures and Piezoelectric Properties of Pb(Zr,Ti)O3 Ceramics

2011 ◽  
Vol 485 ◽  
pp. 3-6
Author(s):  
Naoki Iwaji ◽  
Chiharu Sakaki ◽  
Nobuyuki Wada ◽  
Hiroshi Takagi ◽  
Shigeo Mori
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Boundary ◽  
Piezoelectric Properties ◽  
Ferroelectric Domain ◽  
Strongly Correlated ◽  
Grain Composition ◽  
Pzt Ceramics ◽  
Domain Structures ◽  
Transmission Electron

We investigated domain structures in Pb(Zr,Ti)O3(PZT) ceramics whose composition lies on the morphotropic phase boundary (MPB) using transmission electron microscopy (TEM) and evaluated the piezoelectric properties of PZT. We found that monoclinic nanosized domains (nanodomains), which form in tetragonal domains, strongly correlated with the piezoelectric properties of PZT. The degree of formation of nanodomains depends on the grain composition. Thus, controlling the homogeneity of grain composition in the ceramics is crucial for optimizing the piezoelectric properties of PZT.

HRTEM study of crystal structures and microstructures of High-Te superconductors YBa2−xSrxCu3Oy (x=0-1.2)

1990 ◽  
Vol 48 (4) ◽  
pp. 58-59
Author(s):  
Yoshio Matsui ◽  
Uk Lee ◽  
Akira Ono ◽  
Shigeo Horiuchi ◽  
Chusei Tsuruta
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Crystal Structures ◽  
Twin Plane ◽  
Orthorhombic Structure ◽  
High Tc ◽  
Domain Structures ◽  
Transmission Electron ◽  
Cation Sites

High-Tc superconducting oxide YBa2Cu3Oy has an orthorhombic structure (a=0. 382, b=0. 389 and c=1. 17nm) with layer sequences of (..BaO CuOx BaO CuO2 Y CuO2 BaO CuOx BaO..) along the c-axis. It usually has twinned microstructure with twin plane {110}, causing associated splitting of some of the diffraction spots. It is well known that these characteristic structures of YBa2Cu3Oy can be affected by partial substitutions of cation sites. For instance, tetragonal structure with a=b is stabilized in the compounds Ba2−xLa1+xCu3Oy and Ba2−xNd1+xCu3Oy . Formations of 90-degree domain structures are also observed in these compounds. Recently, Ono et al. prepared a series of compounds, YBa2−xSrxCu3Oy (x=0 to 1.2), to study the effects of substituting Ba by Sr and found the gradual decrease of Tc with increase of x. In the present study, change of the crystal structures and the microstructures in a series of compounds are examined by means of high-resolution transmission electron microscopy.

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