In situ oxygen surface exchange coefficient measurements on lanthanum strontium ferrite thin films via the curvature relaxation method

Here, an in situ curvature relaxation (κR) method was used to measure chemical oxygen surface exchange coefficients ( k ˜ ʹ s ) under well-characterized stress, temperature, and oxygen partial pressure conditions. These k ˜ ʹ s were measured by analyzing the transient curvature of yttria stabilized zirconia supported La0.6Sr0.4FeO3 − δ thin films reacting to oxygen partial pressure step changes. The sputtered thin film k ˜ ʹ s measured here were consistent with extrapolated bulk sample k ˜ ʹ s , but larger than those reported for pulsed laser deposited thin films. This is the first time that the curvature response of a system has been used to characterize thin film oxygen surface exchange kinetics. The simultaneous measurement of film stress and k ˜ provided by the curvature relaxation method may help explain the large k ˜ discrepancies observed in the literature.