Local Charge Disproportion in a High-Performance Perovskite

被引：66

作者：

Arnold, Mirko ^{[1
]}

Xu, Qiang ^{[2
]}

Tichelaar, Frans D. ^{[2
]}

Feldhoff, Armin ^{[1
]}

机构：

[1] Leibniz Univ Hannover, Inst Phys Chem & Electrochem, D-30167 Hannover, Germany

[2] Delft Univ Technol, Natl Ctr High Resolut Electron Microscopy, NL-2628 CJ Delft, Netherlands

来源：

CHEMISTRY OF MATERIALS | 2009年 / 21卷 / 04期

关键词：

TRANSITION-METAL OXIDES; FINE-STRUCTURES; OXYGEN; EELS; 3D; EDGE; IRON; STATE;

D O I：

10.1021/cm802779f

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The temperature-dependent local charge disproportion in the (Ba0.5Sr0.5)(Co0.8Fe0.2)O-3-delta perovskite-type oxide (denoted as BSCF) was monitored by in situ electron energy-loss spectroscopy applying monochromized electrons in a transmission electron microscope. At elevated temperatures, oxygen is removed from the crystal lattice in these perovskite-type oxides that is due to a reduction of the transition metal sites. To determine the site-specific valence in the BSCF perovskite, we measured the cobalt and iron L-edges and the oxygen K-edge on increasing the temperature from 298 to 1223 K. It was found that the loss of oxygen at elevated temperatures is mainly due to a reduction of the cobalt site compared to the iron site. The understanding of the site specific redox behavior in this material is important in explaining its long-term instability at intermediate temperatures, which has not been elucidated priory this study.

引用

页码：635 / 640

页数：6

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