Oriented thin films of La0.5Sr0.5CoO3-x were deposited on single-crystal 9.5 mol% Y2O3 stabilized ZrO2 by laser deposition. The films were infused with O-18 by exchange with 20 kPa O-2 at 300-400 degrees C, then quenched and depth profiled by secondary ion mass spectroscopy. Analysis of the depth profiles revealed a significant barrier to interfacial transport at these relatively low temperatures.