title: Apparent Oxygen Uphill Diffusion in La0.8Sr0.2MnO3Thin Films upon Cathodic Polarization.
abstract: The impact of cathodic bias on oxygen transport in La0.8Sr0.2MnO3(LSM) thin films was investigated. Columnar-grown LSM thin films with different microstructures were deposited by pulsed laser deposition.18O tracer experiments were performed on thin film microelectrodes with an applied cathodic bias of -300 or -450 mV, and the microelectrodes were subsequently analyzed by time-of-flight secondary ion mass spectrometry. The18O concentration in the cathodically polarized LSM microelectrodes was strongly increased relative to that in the thermally annealed film (without bias). Most remarkable, however, was the appearance of a pronounced18O fraction maximum in the center of the films. This strongly depended on the applied bias and on the microstructure of the LSM thin layers. The unusual shape of the18O depth profiles was caused by a combination of Wagner-Hebb-type stoichiometry polarization of the LSM bulk, fast grain boundary transport and voltage-induced modification of the oxygen incorporation kinetics.
authors.affiliation: Institute of Chemical Technologies and Analytics Vienna University of Technology Getreidemarkt 9 Vienna A-1060 Austria.
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Huber
authors.affiliation: Institute of Chemical Technologies and Analytics Vienna University of Technology Getreidemarkt 9 Vienna A-1060 Austria.
authors.forename: Edvinas
authors.initials: E
authors.lastname: Navickas
authors.affiliation: Institute of Chemical Technologies and Analytics Vienna University of Technology Getreidemarkt 9 Vienna A-1060 Austria.
authors.forename: Gernot
authors.initials: G
authors.lastname: Friedbacher
authors.affiliation: Institute of Chemical Technologies and Analytics Vienna University of Technology Getreidemarkt 9 Vienna A-1060 Austria.
authors.forename: Herbert
authors.initials: H
authors.lastname: Hutter
authors.affiliation: Institute of Chemical Technologies and Analytics Vienna University of Technology Getreidemarkt 9 Vienna A-1060 Austria.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Fleig
keywords: cathodic bias; grain boundaries; mass spectrometry; thin films; tracer diffusion