Possible origin of electronic phase separation in La0.7 Ca 0.3 MnO3

Abstract

The effect of substrate strain on the electronic valence band structure of La0.7 Ca0.3 MnO3 thin films has been investigated. For this purpose La0.7 Ca0.3 MnO3 thin films have been simultaneously grown on SrTiO3 and LaAlO3 substrates using pulsed laser deposition technique. The chemical characterization of these samples is carried out by core level x-ray photoelectron spectroscopy and the structural characterization by x-ray diffraction. Our experiments confirm that all these samples have the 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 a large effect on the valence band of La0.7 Ca0.3 MnO3. The results are explained on the basis of change in the crystal field splitting due to Mn-O bond length. © 2008 American Institute of Physics.