AI Article Synopsis
- The origin of phase separation in manganites, like La1-xCaxMnO3, is still not fully understood, but new experimental evidence sheds light on it.
- Researchers found that at low hole densities, Mn(4+) holes cluster around Ca(2+) ions, causing localized holes that contribute to nanocluster formation.
- This clustering limits the hopping of electrons between Mn ions, which is why perovskites with low hole density exhibit insulating properties.
Article Abstract
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 La1-xCaxMnO3 system. For low hole densities, direct evidence of Mn(4+) holes localization around Ca(2+) 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 Mn(3+) and Mn(4+) 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 Mn(4+) holes are bound to substitutional divalent Ca(2+) ions.
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| http://dx.doi.org/10.1021/acs.nanolett.5b04704 | DOI Listing |
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