Regensburg 2002 – wissenschaftliches Programm

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MA: Magnetismus

MA 10: Poster : Dünne Schichten(1-21),Spinabh.Transp.(22-39),Exch.Bias(40-51),Spindyn.(52-55),Mikromag.(56-66),Partikel(67-74),Abb.Verf.(75-77),Oberfl.+Spinelektr.+Elektr.Theo+Mikromag(75-87),PÜ+Aniso+Werkst/Leg.(88-103),Mol.Mag.+N-dim+Messm.+Postdead(104-111

MA 10.109: Poster

Dienstag, 12. März 2002, 15:00–19:00, Bereich A

Magnetic Properties of the Complex Cu-Vandate KCu₅V₃O₁₃ — •P. Lemmens^1,2, J. Pommer¹, A. Ionescu¹, G. Güntherodt¹, H.-H. Henning², M. Birke², D. Baabe², D. Mienert², G. Roth³, H.-A. Krug v. Nidda⁴, J. Deisenhofer⁴, H. Kageyama⁵, Y. Ueda⁵, Z. Hiroi⁵, and M. Takigawa⁵ — ¹2. Physikalisches Institut, RWTH Aachen — ²IMNF, TU Braunschweig — ³Institut für Kristallographie, RWTH Aachen — ⁴Experimentalphysik 5, Univ. Augsburg — ⁵ISSP Tokyo, Kashiwa, Chiba

The compound KCu₅V₃O₁₃ is a complex Oxo-Cu-vanadate with 5 independent Cu-sites (s=1/2) per unit cell that are coordinated on a ladder of spin tetrahedra or triangles. Magnetic and structural properties of this compound are compared to related Cu-divanadates. The observed instabilities in specific heat and magnetic susceptibility at 7.5K and 3.7K correspond to antiferromagnetic ordering as shown by µ-SR experiments. These data and corresponding NMR experiments give hints that spin fluctuations are partly conserved through the transitions. This is supported by specific heat data. At high temperatures evidence is found in ESR experiments for a partial charge transfer between Cu and V. The interplay of these dynamics with the complex and low symmetry exchange topology leads in a medium temperature range to the observation of anisotropic switching phenomena in the magnetic susceptibility.
We acknowledge support by DFG SPP1073.