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Title: Abnormal Pressure-Induced Photoluminescence Enhancement and Phase Decomposition in Pyrochlore La 2 Sn 2 O 7

Authors:
 [1];  [2];  [2];  [3];  [3];  [3];  [3];  [4]
  1. State Key Laboratory of Superhard Materials, Department of Physics, Jilin University, Changchun 130012 China, Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 China
  2. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 China
  3. State Key Laboratory of Superhard Materials, Department of Physics, Jilin University, Changchun 130012 China
  4. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 China, High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne IL 60439 USA
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1380005
Grant/Contract Number:
FG02-99ER45775
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Advanced Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 34; Related Information: CHORUS Timestamp: 2017-09-07 15:57:31; Journal ID: ISSN 0935-9648
Publisher:
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
Germany
Language:
English

Citation Formats

Zhao, Yongsheng, Li, Nana, Xu, Cong, Li, Yan, Zhu, Hongyu, Zhu, Pinwen, Wang, Xin, and Yang, Wenge. Abnormal Pressure-Induced Photoluminescence Enhancement and Phase Decomposition in Pyrochlore La 2 Sn 2 O 7. Germany: N. p., 2017. Web. doi:10.1002/adma.201701513.
Zhao, Yongsheng, Li, Nana, Xu, Cong, Li, Yan, Zhu, Hongyu, Zhu, Pinwen, Wang, Xin, & Yang, Wenge. Abnormal Pressure-Induced Photoluminescence Enhancement and Phase Decomposition in Pyrochlore La 2 Sn 2 O 7. Germany. doi:10.1002/adma.201701513.
Zhao, Yongsheng, Li, Nana, Xu, Cong, Li, Yan, Zhu, Hongyu, Zhu, Pinwen, Wang, Xin, and Yang, Wenge. Mon . "Abnormal Pressure-Induced Photoluminescence Enhancement and Phase Decomposition in Pyrochlore La 2 Sn 2 O 7". Germany. doi:10.1002/adma.201701513.
@article{osti_1380005,
title = {Abnormal Pressure-Induced Photoluminescence Enhancement and Phase Decomposition in Pyrochlore La 2 Sn 2 O 7},
author = {Zhao, Yongsheng and Li, Nana and Xu, Cong and Li, Yan and Zhu, Hongyu and Zhu, Pinwen and Wang, Xin and Yang, Wenge},
abstractNote = {},
doi = {10.1002/adma.201701513},
journal = {Advanced Materials},
number = 34,
volume = 29,
place = {Germany},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on July 10, 2018
Publisher's Accepted Manuscript

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

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  • The structural transitions of the pyrochlore, Cd{sub 2}Nb{sub 2}O{sub 7}, at pressures up to 32.5 GPa have been investigated by in situ Raman scattering and angle-dispersive x-ray diffraction (ADXRD) methods. The x-ray diffraction results reveal that small amounts ({approx}7%) of metallic cadmium form by chemical decomposition at pressures greater than 4 GPa. Both Raman and XRD results indicate that a pressure-induced structural distortion from pyrochlore to defect fluorite occurs in pyrochlore Cd{sub 2}Nb{sub 2}O{sub 7} at pressures of 12-14 GPa. Subsequently, a new high-pressure phase formed and the phase transition was complete at {approx}27 GPa. The high-pressure phase is eithermore » monoclinic or orthorhombic and transforms to either the pyrochlore (or defect fluorite) structure or the amorphous state when quenched to ambient conditions. Energy dispersive spectroscopy (EDS) analysis and high-resolution transmission electron microscopy (HRTEM) observation of the quenched sample confirmed the Cd loss and resulting mixture of ordered pyrochlore, defect fluorite, high-pressure phase, as well as amorphous domains.« less
  • The structural transitions of the pyrochlore, Cd{sub 2}Nb{sub 2}O{sub 7}, at pressures up to 32.5 GPa have been investigated by in situ Raman scattering and angle-dispersive x-ray diffraction (ADXRD) methods. The x-ray diffraction results reveal that small amounts ({approx}7%) of metallic cadmium form by chemical decomposition at pressures greater than 4 GPa. Both Raman and XRD results indicate that a pressure-induced structural distortion from pyrochlore to defect fluorite occurs in pyrochlore Cd{sub 2}Nb{sub 2}O{sub 7} at pressures of 12-14 GPa. Subsequently, a new high-pressure phase formed and the phase transition was complete at {approx}27 GPa. The high-pressure phase is eithermore » monoclinic or orthorhombic and transforms to either the pyrochlore (or defect fluorite) structure or the amorphous state when quenched to ambient conditions. Energy dispersive spectroscopy (EDS) analysis and high-resolution transmission electron microscopy (HRTEM) observation of the quenched sample confirmed the Cd loss and resulting mixture of ordered pyrochlore, defect fluorite, high-pressure phase, as well as amorphous domains.« less
  • The electrical properties of sintered specimens of new compounds Ca[sub 2x]Ce[sub 2[minus]2x]Sn[sub 2]O[sub 7] (0.35 [le] x [le] 0.43) and Sr[sub 0.7]Ce[sub 1.3]Sn[sub 2]O[sub 7] with cubic pyrochlore structure were measured as functions of temperature and oxygen partial pressure. These compounds showed semiconductive behavior. The negative Seebeck coefficient indicates these compounds to be n-type, and the dominant carrier is the electron. In these compounds, almost no oxygen nonstoichiometry was detected in the range of oxygen partial pressure (pO[sub 2]) from 1 to 10[sup [minus]3.5] atm with thermogravimetric analysis. Moreover, the electrical conductivity slightly increased as pO[sub 2] decreased from 1more » to 10[sup [minus]15] atm. Since it was required that part of the Ce ions should be trivalent to maintain the electrical neutrality in the whole crystal from the point of view of the chemical composition, the formation of the carriers was explained by the substitution of trivalent Ce ion for Ca. The Seebeck coefficient increased as temperature increased from 780 to 1,273 K, so the conduction mechanism of these new compounds is probably small polaron hopping. 16 refs., 4 figs.« less