Electrochemical properties of dense (La, Sr)MnO3-δ films produced by pulsed laser deposition

The electrical conductivity and the electrochemical properties of dense La0.85Sr0.15MnO3 - delta (LSM) films, prepared using Pulsed Laser Deposition (PLD) have been investigated. The nano-structure of the LSM films has been characterized using scanning electron microscopy (SEM). The oxygen transport properties of the films were studied using electrochemical impedance spectroscopy (EIS) on symmetrical cells. Electrical conductivity measurement were carried out in an oxygen partial pressure range from 1 to 0.0032 atm, and a temperature range from 950 to 700 degrees C. The electrical conductivity at 800 degrees C was 116S cm(-1) and did not vary with the p(O2). Impedance spectra were recorded in the temperature range from 600 to 950 degrees C in the oxygen partial pressure range from 0.06 to 1.00 atm. At 900 degrees C and 1.00 atm the area specific resistance was 30.6 Omega cm(2) and an activation energy of 2.7 eV was found. The ASR increased with decreasing p(O2) Based on the impedance spectra an oxide ion conductivity of 5.0 x 10(-1) S cm(-1) was found at 900 degrees C and p(O2)= 1.00 atm. The characteristic length, at which the oxide transport reaction switch from being limited by bulk diffusion to that of surface exchange, was estimated to be approximately 220 and 130 nm at 700 and 900 degrees C, respectively. (C) 2012 Elsevier B.V. All rights reserved.