Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)

MA 18.34: Poster

Dienstag, 26. Februar 2008, 15:15–18:30, Poster E

Evolution of the crystal structure of YMn_2−xFe_xO₅ due to iron doping and DFT calculations for the x=1 compound — •Torsten Weißbach¹, Dmitri Souptel², Günter Behr², Thomas Führlich¹, Falk Wunderlich¹, Dirk C. Meyer¹ und Sibylle Gemming³ — ¹Institut für Strukturphysik der TU, Dresden, Germany — ²Institut für Festkörper-und Werkstoffforschung (IFW), Dresden, Germany — ³FZ Dresden-Rossendorf, Dresden, Germany

YMnFeO₅ is a ferrimagnet below 165 K[1]. Its crystal structure is derived from that of the ferromagnetic and low-temperature ferroelectric YMn₂O₅ by occupation of the Mn position possessing pyramidal oxygen environment with Fe; the other Mn site is coordinated by oxygen in an octahedral manner. Powder samples for x = 0, 0.25, 0.5, 1 [2] were inspected by X-ray powder diffraction and EXAFS, single crystals (x = 0.07, 0.25) by single-crystal X-ray diffraction methods. The structure data show a significant displacement of Fe within the oxygen pyramid, while the Mn position remains nearly constant with respect to the surrounding oxygen atoms. All-electron density-functional calculations in the LSDA+U approximation for the x = 1 compound [3] are in good agreement with the collinear, commensurate ferrimagnetic ordering of the magnetic moments as proposed in [1].

[1] Munoz, A. et al., Chem. Mater. 16, 4087 (2004); [2] all materials prepared by D. Souptel at IFW Dresden; [3] FPLO: Koepernik, K. et al., Phys. Rev. B 59, 1743 (1999)