Microstructure and high temperature transport properties of high quality epitaxial SrFeO3 − δ films

We report the high temperature electronic transport properties of SrFeO3 − δ epitaxial thin films obtained by pulsed laser deposition on NdGaO3(110) substrates. The films show total conductivity higher than the bulk material and apparent activation energy of about 0.12 eV in O2, lower than reported values for SrFeO3 − δ films. The conductivity dependence with oxygen partial pressure shows a power dependence with an exponent close to + 1/4, in agreement with expected point defect equilibrium. For a given oxygen partial pressure, the temperature coefficient of resistance (TCR) shows a low positive value of about 1.5–2.5 10− 3 K− 1, which is still suitable for resistive oxygen sensing applications. The transport properties of the films are discussed in view of their particular microstructure.