A high-entropy manganite in an ordered nanocomposite for long-term application in solid oxide cells.

The implementation of nano-engineered composite oxides opens up the way towards the development of a novel class of functional materials with enhanced electrochemical properties. Here we report on the realization of vertically aligned nanocomposites of lanthanum strontium manganite and doped ceria with straight applicability as functional layers in high-temperature energy conversion devices. By a detailed analysis using complementary state-of-the-art techniques, which include atom-probe tomography combined with oxygen isotopic exchange, we assess the local structural and electrochemical functionalities and we allow direct observation of local fast oxygen diffusion pathways. The resulting ordered mesostructure, which is characterized by a coherent, dense array of vertical interfaces, shows high electrochemically activity and suppressed dopant segregation. The latter is ascribed to spontaneous cationic intermixing enabling lattice stabilization, according to density functional theory calculations. This work highlights the relevance of local disorder and long-range arrangements for functional oxides nano-engineering and introduces an advanced method for the local analysis of mass transport phenomena

Interface structure governed by plastic and structural dissimilarity in perovskite La 0.7 Sr 0.3 MnO 3 nanodots on rock-salt MgO substrates

International audienceSelf-assembled La0.7Sr0.3MnO3 perovskite nanodots have been grown on highly mismatched rock-salt type MgO substrates by chemical solution deposition. The interfacial dislocation structure indicates that the relaxation mechanism is governed by the easy glide of MgO 1/2〈101〉{101} dislocations towards the interface, where they dissociate into misfit-relieving and tilting components. The latter induce a 4-domain tilt pattern superimposed to the main cube-on-cube epitaxial orientation. It is shown that the inheritance of the rotational component of the Burgers vector has detrimental consequences on the interfacial quality, evidencing the impact of structural and plastic dissimilarity on the design of self-assembled nanostructures