SrMnO3 Thermochromic Behavior Governed by Size-Dependent Structural Distortions

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• 作者：Irma N. González-Jiménez ; Esteban Climent ; Almudena Torres-Pardo ; María Hernando ; Ana E. Sánchez-Peláez ; Francisco Fernández-Martínez ; M. Teresa Fernández Díaz ; José M. González-Calbet ; Alicia de Andrés ; Áurea Varela ; Marina Parras
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：April 18, 2016
• 年：2016
• 卷：55
• 期：8
• 页码：3980-3991
• 全文大小：751K
• 年卷期：0
• ISSN：1520-510X

文摘

The influence of particle size in both the structure and thermochromic behavior of 4H-SrMnO<sub>3sub> related perovskite is described. Microsized SrMnO<sub>3sub> suffers a structural transition from hexagonal (P6<sub>3sub>/mmc) to orthorhombic (C222<sub>1sub>) symmetry at temperature close to 340 K. The orthorhombic distortion is due to the tilting of the corner-sharing Mn<sub>2sub>O<sub>9sub> units building the 4H structural type. When temperature decreases, the distortion becomes sharper reaching its maximal degree at ∼125 K. These structural changes promote the modification of the electronic structure of orthorhombic SrMnO<sub>3sub> phase originating the observed color change. nano-SrMnO<sub>3sub> adopts the ideal 4H hexagonal structure at room temperature, the orthorhombic distortion being only detected at temperature below 170 K. A decrease in the orthorhombic distortion degree, compared to that observed in the microsample, may be the reason why a color change is not observed at low temperature (77 K).