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MA: Magnetismus

MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)

MA 20.148: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

XPS and Mössbauer studies of grain boundary effects in highly ordered Sr₂FeMoO₆ — •M. Raekers¹, C. Taubitz², K. Kuepper², H. Hesse¹, I. Balasz³, I. G. Deac³, S. Constantinescu⁴, M. Valeanu⁴, E. Burzo³, and M. Neumann¹ — ¹Universität Osnabrück, Fachbereich Physik, Barbarastr. 7, D-49069 Osnabrück, Germany — ²Institut für Ionenstrahlphysik und Materialforschung, Forschungszentrum Rossendorf, 01314 Dresden, Germany — ³Faculty of Physics, Babes-Bolyai University, 3400, Cluj-Napoca, Romania — ⁴National Institute of Materials Physics, P.O. Box MG-07, Bucharest, Romania

Sr₂FeMoO₆ is magneto resistance (MR) compound which has attracted much attention in the last years. Our work group has already studied this compound intensely[1,2]. Here we present the oxidation states of Fe and Mo and the presence of grain boundaries in the magneto resistance (MR) compound Sr₂FeMoO₆ by means of x-ray photoelectron spectroscopy (XPS) and Mössbauer spectroscopy. XPS of the Mo 3d and Fe 3s core levels is indicating a mixed valence state involving around 30% Fe³⁺- Mo⁵⁺ and 70% Fe²⁺- Mo⁶⁺ states. Mössbauer studies confirm the presence of a valence fluctuation state and an essential amount of grain boundaries in the present Sr₂FeMoO₆ crystal. The influence of the grain boundaries will be discussed.

[1] J. Phys.: Condens. Matter 17 (27): 4309-4317 (2005)

[2] phys. stat. sol. (a), 201, No. 15, 3252-3256 (2004)