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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.17: Poster

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

Excitation spectrum of the novel frustrated 2D s=1/2 system (CuCl)LaNb₂O₇ — •V. Gnezdilov¹, P. Scheib², P. Lemmens², Yu.G. Pashkevich³, T. Kitano⁴, Y. Ajiro⁴, N. Oba⁴, K. Yoshimura⁴, and H. Kageyama⁴ — ¹B.I. Verkin Inst. for Low Temp. Physics, NASU, Ukraine — ²IPKM, TU Braunschweig, D-38106 Braunschweig, Germany — ³A.A. Galkin Donetsk Phystech, NASU, 83144 Donetsk, Ukraine — ⁴Dept. Chem., Kyoto Univ., Kyoto 606-8502, Japan

We report on the magnetic properties and Raman scattering data of the double-layered perovskite (CuCl)LaNb₂O₇ with a square lattice of s=1/2, prepared by topotactic ion-exchange reactions. Thermodynamic and spectroscopic experiments show a spin gap of ≈ 2 meV. Evidence for competing ferro- and antiferromagnetic exchange pathes connecting nearest and second-nearest-neighbors, respectively, exist. The role of the lattice system for the magnetic properties is critically discussed. This work has been supported partly by the ESF-HFM.