Oxygen Bonding in Bismuth Layered Compounds SrBi2Ta2O9

2007 ◽  
Vol 997 ◽  
Author(s):  
Dong Su ◽  
Nan Jiang ◽  
Jianguo Wen ◽  
Jianshe Liu
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Local Density ◽  
Layered Compounds ◽  
Density Approximation ◽  
Electron Loss ◽  
Density Of State ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Fine Structures ◽  
Z Contrast

AbstractWith the help of the high resolution Z-contrast scanning transmission electron microscopy (STEM), the near edge fine structures of the electron loss spectroscopy (EELS) arises from different layers are investigated in SBT. The EELS spectra are interpreted by comparing with the calculation using linearnized augment plane wave (LAPW) method within the local density approximation (LDA). The oxygen bonding nature in different layers are discussed. In Bi2O2 layer, oxygen 2p state interacted with the Bi 6p state leads to a high t2g state in density of state while in SrTa2O7 layer, oxygen 2p state hybridized with Ta 5d and Sr 5d, which leads a higher eg state than t2g state.

scholarly journals FEI Tecnai G2 F20

2016 ◽  
Vol 2 ◽  
Author(s):  
Martina Luysberg ◽  
Marc Heggen ◽  
Karsten Tillmann
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Conventional Imaging ◽  
Electron Loss ◽  
High Angle ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Set Up ◽  
Elemental Maps

The FEI Titan Tecnai G2 F20 is a versatile transmission electron microscope which is equipped with a Gatan Tridiem 863P post column image filter (GIF) and a high angle energy dispersive X-ray (EDX) detector. This set up allows for a variety of experiments such as conventional imaging and diffraction, recording of bright- and dark-field scanning transmission electron microscopy (STEM) images, or acquiring elemental maps extracted from energy electron loss spectra (EELS) or EDX signals.

Observing dislocations with ADF-STEM

1991 ◽  
Vol 49 ◽  
pp. 668-669
Author(s):  
Y. Huang ◽  
J. M. Cowley
Keyword(s):  
Material Science ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
High Angle ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Contrast Mechanism ◽  
Annular Dark Field ◽  
Annular Detector ◽  
Z Contrast

Scanning transmission electron microscopy (STEM) with a high angle annular detector has become a useful technique in material science. The atomic number sensitive contrast (Z-contrast) of the Annular Dark-Field (ADF) image is good for looking at the distribution of heavy elements in a relatively light substrate. In many cases the impurity distributions are substantially affected by the defects in the materials and their interaction with the impurities. Therefore it is also desirable to observe defects with ADF images. This is possible and has some advantages over normal STEM. We have studied the ADF imaging of dislocations, its contrast mechanism and visibility in the ADF image.

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