  The effect of substrate strain on the electronic valence band structure of
La0.7Ca0.3MnO3 thin films has been investigated. For this purpose
La0.7Ca0.3MnO3 thin films have been simultaneously grown on SrTiO3 and LaAlO3
substrates using pulsed laser deposition technique. These samples were
characterized by x-ray diffraction, x-ray reflectivity, core level x-ray
photoelectron spectroscopy, and scanning electron microscopy measurements. Our
experiments confirmed that all these samples have same chemical composition but
different strain configuration. The electronic structure of these samples is
probed through valence band spectroscopy measurements on Indus-1 synchrotron
x-ray source. We observe that strain has large effect on the valence band
electronic structure of La0.7Ca0.3MnO3. The results are explained on the basis
of strain induced orbital occupancy and change in the crystal field splitting
due to Mn-O bond length.
