Curie-temperature enhancement of electron-doped Sr2FeMoO6 perovskites studied by photoemission spectroscopy -: art. no. 115101

We report here on the electronic structure of electron-doped half-metallic ferromagnetic perovskites such as Sr2-xLaxFeMoO6 (x=0-0.6) as obtained from high-resolved valence-band photoemission spectroscopy (PES). By comparing the PES spectra with band-structure calculations, a distinctive peak at the Fermi level E-F with predominantly (Fe+Mo) t(2g)(down arrow) character has been evidenced for all samples, irrespectively of the x values investigated. Moreover, we show that the electron doping due to the La substitution provides selectively delocalized carriers to the t(2g)(down arrow) metallic spin channel. Consequently, a gradual rising of the density of states at the E-F has been observed as a function of the La doping. By changing the incoming photon energy we have shown that electron doping mainly rises preferentially the Mo density of states. These findings provide fundamental clues for understanding the origin of ferromagnetism in these oxides and shall be of relevance for tailoring oxides having still higher T-C.