Abstract
Strontium doped lanthanum manganite (La0.8Sr0.2)0.95MnO3 (LSM) and lanthanum strontium cobalt ferrite La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) thin films were grown by pulsed laser deposition (PLD) on single crystal substrates. Total X-ray Reflection Fluorescence (TXRF) reveals the evolution of surface composition due to annealing at 800 C. X-ray Absorption Near Edge Spectroscopy (XANES) provides insight into the local electronic structure of the cations. LSM manganese concentration is higher at the surface than in the bulk in as-deposited films. Annealing further enhances surface manganese segregation and irreversibly changes the manganese XANES spectra. Surface strontium is greatly enhanced in LSCF samples quenched from 800 C, however the strontium is reabsorbed into the film when allowed to cool slowly.