Low-Temperature Superionic Conductivity in Strained Yttria-Stabilized Zirconia

✍ Scribed by Michael Sillassen; Per Eklund; Nini Pryds; Erik Johnson; Ulf Helmersson; Jørgen Bøttiger

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 487 KB
• Volume: 20
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/adfm.201000071

✦ Synopsis

Abstract

Very high lateral ionic conductivities in epitaxial cubic yttria‐stabilized zirconia (YSZ) synthesized on single‐crystal SrTiO~3~ and MgO substrates by reactive direct current magnetron sputtering are reported. Superionic conductivities (i.e., ionic conductivities of the order ∼1 Ω^−1^cm^−1^) are observed at 500 °C for 58‐nm‐thick films on MgO. The results indicate a superposition of two parallel contributions – one due to bulk conductivity and one attributable to conduction along the film–substrate interface. Interfacial effects dominate the conductivity at low temperatures (<350 °C), showing more than three orders of magnitude enhancement compared to bulk YSZ. At higher temperatures, a more bulk‐like conductivity is observed. The films have a negligible grain‐boundary network, thus ruling out grain boundaries as a pathway for ionic conduction. The observed enhancement in lateral ionic conductivity is caused by a combination of misfit dislocation density and elastic strain in the interface. These very high ionic conductivities in the temperature range 150–500 °C are of great fundamental importance but may also be technologically relevant for low‐temperature applications.