Preparation of La 0.9Sr 0.1Ga 0.85Mg 0.15O 2.875 thin films by pulsed-laser deposition and conductivity studies

Abstract

Thin films La 0.9Sr 0.1Ga 0.85Mg 0.15O 2.875 (LSGMO), an oxide ion conducting electrolyte material, which has potential application in oxygen sensor development and in solid oxide fuel cells, have been prepared by pulsed-laser deposition. Preparation of thin film under high-vacuum condition gives a stoichiometric LSGMO, whereas film prepared under oxygen atmosphere is not stoichiometric. Highly oriented films of LSGMO are obtained on SrTiO 3 STO(001), whereas polycrystalline films are obtained on sapphire(0001), quartz, and calcia-stabilized zirconia substrates. Film conductivity is measured by ac impedance analysis. Film on sapphire shows higher conductivity compared to that of the film on STO by a factor of 10 at 730°C. The activation energies for films on sapphire and STO are 0.7 and 0.82 eV, respectively, in the temperature region between 630 and 930°C. © 2002 American Institute of Physics.