Enhancement of Ionic Conductivity in Sm-Doped Ceria/Yttria-Stabilized Zirconia Heteroepitaxial Structures

✍ Scribed by Simone Sanna; Vincenzo Esposito; Antonello Tebano; Silvia Licoccia; Enrico Traversa; Giuseppe Balestrino

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 824 KB
• Volume: 6
• Category: Article
• ISSN: 1613-6810
• DOI: 10.1002/smll.200902348

✦ Synopsis

Recent developments in the fi eld of thin-fi lm growth technologies have allowed control at an atomic level of deposited layers, thus opening new perspectives in the fi eld of engineering of multilayers and heterostructures based on complex oxides. [ 1 ] In particular, it is expected that oxide heterostructures, with almost ideal interfaces, may lead to interesting artifi cial materials with novel properties. Artifi cial thin-fi lm oxide structures make the already complex individual bulk properties even more interesting through their interaction at the interface. Following such an approach, a number of heterostructures have been tailored which show extraordinary properties that do not belong to the individual layers. These range from superconductivity at the interface between nonsuperconducting layers to high-mobility 2D conductivity at the interface between insulating oxides. [ 2 , 3 ] The number of possible combinations of these oxides is enormous, and the potential for novel behavior having practical applications represents a strong motivation for this research.

The same approach can be applied to heterostructures based on oxide ionic conductors provided that the issues concerning structural match at the interface are solved. The interest in heterostructures based on oxide ionic conductors is driven by the space-charge-zone effects at the interface, which can increase the charge-carrier concentration locally, and by interface mobility effects, the latter being of particular relevance in the case of materials with high defect density and relatively low mobility. The potential impact of oxide ionic conductor superlattices has been shown for superlattices based on CaF 2 and BaF 2 layers, grown by molecular beam epitaxy, which exhibited an increase in ionic conductivity