Optical absorption in epitaxial La1−xSrxFeO3 thin films

Abstract

We report the dependence of optical absorption on Sr concentration in La1−xSrxFeO3 (LSFO) (x≤0.4) perovskite thin films. Strained epitaxial films were deposited on SrTiO3 substrates using oxide molecular beam epitaxy. We find systematic changes in the optical absorption spectra with increasing x including a red-shift of transition energies and the increasing presence of a lower energy transition within the fundamental gap of pure LaFeO3. These results serve as a demonstration of the complex manner in which absorption spectra can be altered in complex oxides via heterovalent A-site substitution.