Pressure-induced phase transition of La2Zr2O7 and La0.5Gd1.5Zr2O7 pyrochlore

被引：13

作者：

Niu, Jingjing ^{[1
,3
]}

Wu, Xiang ^{[2
]}

Zhang, Haibin ^{[3
]}

Qin, Shan ^{[1
]}

机构：

[1] Peking Univ, MOE, Sch Earth & Space Sci, Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China

[2] China Univ Geosci Wuhan, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Hubei, Peoples R China

[3] China Acad Engn Phys, Inst Nucl Phys & Chem, Innovat Res Team Adv Ceram, Mianyang 621900, Sichuan, Peoples R China

来源：

RSC ADVANCES | 2019年 / 9卷 / 33期

基金：

中国国家自然科学基金;

关键词：

ELECTRICAL-CONDUCTIVITY; TRANSFORMATIONS; OXIDES;

D O I：

10.1039/c9ra03438b

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

In situ high-pressure experiments on La2Zr2O7 and La0.5Gd1.5Zr2O7 have been carried out at up to approximately 40 GPa using synchrotron X-ray diffraction and Raman spectroscopy combined with a diamond anvil cell technique. Both La2Zr2O7 and La0.5Gd1.5Zr2O7 undergo a phase transition from a pyrochlore phase (Fd3m) into a cotunnite-like phase (Pnma) at 22.7 and 23.3 GPa, respectively. This type of phase transition is mainly controlled through the order-disorder occupancy of cations, and Gd3+ substitution of La3+ reduces the stability of zirconate pyrochlore. However, abnormal changes to the unit-cell volumes and vibrational modes observed at 5.5 GPa in La2Zr2O7 and 6.5 GPa in La0.5Gd1.5Zr2O7 are attributed to an anion disorder in the pyrochlore.

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收藏

页码：18954 / 18962

页数：9

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