Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: Multiferroics

MA 20.12: Vortrag

Mittwoch, 27. Februar 2008, 17:00–17:15, EB 202

Magnetization density in TbMnO₃ single crystals — •de Groot Joost¹, Kentzinger Emmanuel¹, Goukassov Arsène², Gillon Beatrice², and Möchel Anne¹ — ¹Forschungszentrum Jülich Gmbh D52425 Jülich IFF-4: Streumethoden — ²Laboratoire Léon Brillouin (LLB), CEA-CNRS, CE Saclay, F-91191 Gif-sur-Yvette Cedex, France

TbMnO₃ belongs to a class of rare earth manganites showing multiferroic behaviour. While neutron diffraction [1] gives evidence for 4f Tb magnetization below the ferroelectric phase transition temperature 26K, hard x-ray resonance exchange scattering [2] clearly shows a magnetic polarization in the Tb 5d states below T_N=41K. In [2] it is argued that a strong coupling exists between the Mn magnetic order and the Tb magnetization. In order to evidence this coupling and to search for induced magnetization on the Oxygen atoms, we performed polarized neutron diffraction using the spin flip method in an external field on a TbMnO₃ single crystal. These experiments were performed on the diffractometer 5C1 at the LLB. We detected a clear antiferromagnetic coupling between the field induced magnetization at the Tb and Mn sites in the paramagnetic phase. We will discuss these results compared to resonant x-ray scattering.

[1] M. Kenzelmann et al.,PRL 95, 087206 (2005)

[2] J. Voigt, J. Persson, J. W. Kim, G. Bihlmayer, Th. Brückel; Phys. Rev. B, 76 (2007), 104431-1