Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.91: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Structural properties of Ru-codoped La_1−xSr_1+xMnO₄ — •O. Schumann¹, D. Senff¹, M. Kriener¹, I. Klassen¹, N. Hollmann¹, T. Lorenz¹, A. Revcolevschi², G. Andre³, F. Bouree³ und M. Braden¹ — ¹II. Physikalisches Institut, Universität zu Köln — ²LPCES, Universite Paris Sud XI — ³Laboratoire Léon Brillouin

We present x-ray and neutron scattering studies on ruthenium co-doped La_1−xSr_1+xMnO₄. This co-doping leads to a suppression of charge, orbital and magnetic order.

La_0.5Sr_1.5MnO₄ is the 2D-analogon of the half-doped 3D-perovskite manganites (Mn³⁺:Mn⁴⁺=1:1). While showing similar charge, orbital and spin order, a CMR effect is only observed in a very high field. As the CMR-effect in the 3D-manganites is due to a competition between antiferromagnetic (insulating) and ferromagnetic (metallic) interactions, this high field indicates a rather stable AF-order in the layered compound. To weaken this order we prepared several single crystals of Ru-codoped La_0.5Sr_1.5MnO₄, with Ru concentrations ranging from 2% up to 30%. Neutron diffraction, magnetization measurements and resistivity measurements shows, that Ruthenium doping rapidly suppress the charge and orbital order. Furthermore we find a ferromagnetic ground-state and an increased magnetoresistivity.