التفاصيل البيبلوغرافية
العنوان: |
Phase constitution, Sr distribution and morphology of self-assembled La-Sr-Co-O composite films prepared by PLD. |
المؤلفون: |
Stämmler, Sebastian1, Merkle, Rotraut1 r.merkle@fkf.mpg.de, Stuhlhofer, Benjamin1, Logvenov, Gennady1, Hahn, Kersten1, van Aken, Peter A.1, Maier, Joachim1 |
المصدر: |
Solid State Ionics. May2017, Vol. 303, p172-180. 9p. |
مصطلحات موضوعية: |
*PULSED laser deposition, *MOLECULAR self-assembly, *COMPOSITE materials, *STRONTIUM, *THIN films, *LANTHANUM compounds |
مستخلص: |
Thin compact La-Sr-Co-O composite films consisting of both (La,Sr)CoO 3‐ δ and (La,Sr) 2 CoO 4+ δ crystallites and a total La:Sr ratio of 70:30 were prepared by phase separation on a single crystal Y-stabilized zirconia substrate using pulsed laser deposition (PLD) from a single target. The self-assembled composite films have grains of about 50 nm lateral extension with a (La,Sr)CoO 3‐ δ /(La,Sr) 2 CoO 4+ δ /O 2 triple phase boundary density of 1.1–2.6·10 5 cm/cm 2 . Sr is accumulated in (La,Sr) 2 CoO 4+ δ at the expense of (La,Sr)CoO 3‐ δ , but less than expected for thermodynamic equilibrium. Insufficient cation diffusivity for complete demixing can cause the formation of metastable La-Sr-Co-O phases: (1) a Co-deficient perovskite phase La 0.7 Sr 0.3 Co 0.9 O 3‐ δ with high oxygen reduction activity, (2) a higher-order Ruddlesden-Popper phase. These results lay the basis for an accurate quantification and understanding of the potentially high oxygen reduction reaction activities of such films. [ABSTRACT FROM AUTHOR] |
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