Interfacial effects in La 2/3 Sr 1/3 MnO 3 thin films with different complex oxide capping layers

Interfacial effects in sputtered La 2/3 Sr 1/3 MnO 3 thin films with different capping layers (MgO, LaAlO 3 , SrTiO 3 , NdGaO 3 , and Au) have been locally investigated by means of x-ray absorption spectroscopy and x-ray magnetic circular dichroism at the Mn L 3,2 -edge. Data were acquired by using the total electron yield detection mode thus guaranteeing maximum sensitivity to the interface. The data show that LaAlO 3 capping almost does not modify the bulklike Mn valence at the interface. In case of SrTiO 3 and Au, the presence of divalent Mn is detected, whereas MgO and NdGaO 3 capping lead to an increase of the Mn valence oxidation state. The modification of the nominal Mn valence state leads to depressed surface magnetization