Electronic Structure of Sr2FeMoO6: X-ray Fluorescence Measurements

Colossal magnetoresistance (CMR) has attracted much attention due to the importance of its potential technological applications as well as the unusual fundamental magnetic properties. During the last decade the interest concentrated on systems based on doped manganites. Their behaviour is well understood in terms of double-exchange mechanism. Most recently, a CMR effect in the ordered double perovskite Sr2FeMoO6 was reported [1]. This compound exhibits intrinsic tunnelling-type magnetoresistance at room temperature. Its structure and fairly high magnetic transition temperature (Tc) have been reported long time ago [2]. The latest investigations have concentrated on the theoretical description of the magnetic and electronic structure of this compound [3,4]. In contrast, experimental investigation dealing with the electronic structure are rare. We report the first SXF measurements done at the ALS Beamline 8.0.1, obtained on polycrystalline samples of Sr2FeMoO6. The conduction and the valence band in Sr2FeMoO6 are known to consist of Fe 3d, O 2p and Mo 4d states. A big advantage of the SXF method is the symmetry-selective absorption-emission process. Starting at the Fe 2p core levels one can excite the electrons to the nd and ns levels due to the selection rules for optical transitions. According to band structur