|
KMID : 0381919990290040471
|
|
Korean Journal of Microscopy
1999 Volume.29 No. 4 p.471 ~ p.477
|
|
|
Observations on the Modulated Structure in Pyrochlore-type Compounds, $In_2(Ti_{1.7}Zn_{0.3})O_{0.67}$ and $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$
|
|
Lee Hwack-Joo
Park Hyun-Min
Cho Yang-Koo
Ryu Hyun
Nahm Sahn
Y. Bando
|
|
|
Abstract
|
|
|
|
Microstructural observations on the pyrochlore-type $Lu_2Ti_2O_7$ and the similar type of compounds, $In_2(Ti_{1.7}Zn_{0.3})O_{6.7}$ and $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$ which were made by the isothermal heat-treatment at 1623K for 18 days in Pt tube, were carried out using a top-entry HRTEM working at 200 kV. The modulated structures were found in both compounds, however, not in $Lu_2Ti_2O_7$. From the electron diffraction pattern analysis, the modulated superlattices are incommensurate and are 2.69 times of sublattices along (220) direction. The high resolution TEM images have shown that the superlattices consist of alternate superlattices which are composed of two or three sublattices, resulting in the average of 2.7 times of sublattices in accordance with the analysis of electron diffraction patterns. The crystal structures of both compounds are found to quite similar to those of pyrochlore, however the evidence that the cubic axes are slightly deviated from right angle. The modulated structure has gradually changed to the unmodulated structure induced by electron irradiation.
|
|
|
KEYWORD
|
|
|
Pyrochlore, $Lu_2Ti_2O_7$, $In_2(Ti_{1.7}Zn_{0.3})O_{6.7}$, $In_2(Ti_{1.7}Mg_{0.3})O_{6.7}$, Modulated structure, Phase transition, Damage by electron beam
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
|