Experimental Evidence of the Origin of Nanophase Separation in Low Hole-Doped Colossal Magnetoresistant Manganites

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• 作者：Raquel Cortés-Gil ; M. Luisa Ruiz-González ; Daniel González-Merchante ; José M. Alonso ; Antonio Hernando ; Susana Trasobares ; María Vallet-Regí ; Juan M. Rojo ; José M. González-Calbet
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：16
• 期：1
• 页码：760-765
• 全文大小：442K
• ISSN：1530-6992

文摘

While being key to understanding their intriguing physical properties, the origin of nanophase separation in manganites and other strongly correlated materials is still unclear. Here, experimental evidence is offered for the origin of the controverted phase separation mechanism in the representative La_1–xCa_xMnO₃ system. For low hole densities, direct evidence of Mn⁴⁺ holes localization around Ca²⁺ ions is experimentally provided by means of aberration-corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy. These localized holes give rise to the segregated nanoclusters, within which double exchange hopping between Mn³⁺ and Mn⁴⁺ remains restricted, accounting for the insulating character of perovskites with low hole density. This localization is explained in terms of a simple model in which Mn⁴⁺ holes are bound to substitutional divalent Ca²⁺ ions.