The colossal magnetoresistance (LaxSn1-x)(y)MnO3-delta films studied by X-ray photoemission spectroscopy

(La-x Sn1-x)(y)MnO3-delta (LSnMO) epitaxial films have been successfully gr own on single-crystal (1 0 0) LaAlO3 substra res by pulsed-laser deposition (PLD). Measurements of magnetic and transport properties show that this ma terial has colossal magnetoresistance (CMR) effect near the insulator-metal (IM) transition and paramagnetic-ferromagnetic (PF) phase transition. The core levels and the valence band of the film have been studied by X-ray pho toemission spectroscopy (XPS). Through the study of angle-resolved X-ray ph otoemission spectroscopy (ARXPS), we find that the terminal layer of LSnMO film is the MnO atomic plane and there is a slight tin separating out in th e film surface. On the basis of the above results and the crystalline struc ture of perovskite oxides, the growth mechanism of the LSnMO heteroepitaxy on (100) LaAlO3 substrate has been discussed. (C) 2000 Elsevier Science B.V . All rights reserved.