Polycrystalline La0.7Sr0.3MnO3 manganite thin films were grown on silicon substrates covered by SiOx amorphous native oxide. Unusual splitting of the manganite layer was found: on the top of an intermediate layer characterised by lower crystalline order, a magnetic robust layer is formed. Curie temperatures of about 325 K were achieved for 70 nm thick films. A strong room temperature XMCD signal was detected indicating high spin polarisation near the surface. (C) 2005 Elsevier Ltd. All rights reserved.