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By using a combination of synchrotron photoemission and a finite element model, the layer-by-layer stoichiometry of pulsed laser deposited La0.7Sr0.3MnO3 (LSMO) thin films is extracted. For 3- and 5-unit-cell films, the LSMO stoichiometry at the LSMO/SrTiO3 interface has been studied, and it is found that the Sr surface segregation is reversed at the lower interface such that it becomes La rich and Sr depleted. Mn is depleted throughout the entire layer, consistent with reports of a magnetically dead' layer and the formation of a Ruddlesden-Popper phase. The depth-averaged Mn concentration is less than 50% of the expected value, suggesting that interface mixing or segregation into the bulk is important, whereas the depth-averaged La and Sr concentrations are close to the expected values. Copyright (c) 2013 John Wiley & Sons, Ltd. |
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