Modulated Structure of the High-TcSuperconductor Bi-Pb-Ca-Sr-Cu-O Studied by High-Resolution Electron Microscopy and Electron Diffraction

1989 ◽  
Vol 28 (Part 2, No. 10) ◽  
pp. L1783-L1786 ◽  
Author(s):  
Yoshihiko Hirotsu ◽  
Osamu Tomioka ◽  
Naoki Yamamoto ◽  
Yoshio Nakamura ◽  
Sigemaro Nagakura ◽  
...  
1988 ◽  
Vol 27 (Part 2, No. 10) ◽  
pp. L1869-L1872 ◽  
Author(s):  
Yoshihiko Hirotsu ◽  
Osamu Tomioka ◽  
Tadakatsu Ohkubo ◽  
Naoki Yamamoto ◽  
Yoshio Nakamura ◽  
...  

2000 ◽  
Vol 56 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Takeo Oku ◽  
Anna Carlsson ◽  
Jan-Olov Bovin ◽  
Christer Svensson ◽  
L. Reine Wallenberg ◽  
...  

The modulated structure of Ag2SnO3, disilver tin trioxide, was investigated by high-resolution electron microscopy and electron diffraction along four different directions. Electron diffraction showed an incommensurate one-dimensional modulated structure with a modulation wavevector of 1/6.4a*. High-resolution images showed a large number of superstructure domains with the size range 10–100 nm and orientations related by hexagonal rotation. The modulation was determined to be displacements along the c axis of the Ag atoms both in octahedral and linear coordination. An approximate structure model with a commensurate sixfold superstructure, with an orthorhombic cell (P212121, a = 2.922, b = 1.267, c = 0.562 nm), is proposed. Calculated images and electron diffraction patterns, based on this model, agree well with experimental observations.


2001 ◽  
Vol 16 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Takeo Oku ◽  
Jan-Olov Bovin ◽  
Iwami Higashi ◽  
Takaho Tanaka ◽  
Yoshio Ishizawa

Atomic positions for Y atoms were determined by using high-resolution electron microscopy and electron diffraction. A slow-scan charge-coupled device camera which had high linearity and electron sensitivity was used to record high-resolution images and electron diffraction patterns digitally. Crystallographic image processing was applied for image analysis, which provided more accurate, averaged Y atom positions. In addition, atomic disordering positions in YB56 were detected from the differential images between observed and simulated images based on x-ray data, which were B24 clusters around the Y-holes. The present work indicates that the structure analysis combined with digital high-resolution electron microscopy, electron diffraction, and differential images is useful for the evaluation of atomic positions and disordering in the boron-based crystals.


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