title: Probing the bulk ionic conductivity by thin film hetero-epitaxial engineering.
abstract: Highly textured thin films with small grain boundary regions can be used as model systems to directly measure the bulk conductivity of oxygen ion conducting oxides. Ionic conducting thin films and epitaxial heterostructures are also widely used to probe the effect of strain on the oxygen ion migration in oxide materials. For the purpose of these investigations a good lattice matching between the film and the substrate is required to promote the ordered film growth. Moreover, the substrate should be a good electrical insulator at high temperature to allow a reliable electrical characterization of the deposited film. Here we report the fabrication of an epitaxial heterostructure made with a double buffer layer of BaZrO3and SrTiO3grown on MgO substrates that fulfills both requirements. Based on such template platform, highly ordered (001) epitaxially oriented thin films of 15% Sm-doped CeO2and 8 mol% Y2O3stabilized ZrO2are grown. Bulk conductivities as well as activation energies are measured for both materials, confirming the success of the approach. The reported insulating template platform promises potential application also for the electrical characterization of other novel electrolyte materials that still need a thorough understanding of their ionic conductivity.
authors.forename: Daniele
authors.initials: D
authors.lastname: Pergolesi
authors.affiliation: CIC Energigune, Albert Einstein 48, E-01510-Miñano (Álava), Spain.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Roddatis
authors.forename: Emiliana
authors.initials: E
authors.lastname: Fabbri
authors.affiliation: Paul Scherrer Institut, Department of General Energy Research, CH-5225, Villigen-PSI, Switzerland.
authors.forename: Christof W
authors.initials: CW
authors.lastname: Schneider
authors.affiliation: Paul Scherrer Institut, Department of General Energy Research, CH-5225, Villigen-PSI, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lippert
authors.affiliation: Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: Enrico
authors.initials: E
authors.lastname: Traversa
authors.affiliation: Department of Materials, Imperial College London, London SW7 2BP, UK.
authors.forename: John A
authors.initials: JA
authors.lastname: Kilner
keywords: high resolution transmission electron microscopy; impedance spectroscopy; ionic conductivity; oxygen ion conductors; pulsed laser deposition