Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.14: Poster

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

Structural and magnetic properties of oxalate-bridged low-dimensional Cu²⁺ spin systems — •Katarina Remović-Langer¹, Volodymyr Pashchenko¹, Andrey Prokofiev¹, Bernd Wolf¹, Michael Lang¹, Jürgen Schreuer², Leonore Wiehl², Eiken Haussühl², and Björn Winkler² — ¹Physikalisches Institut, J. W. Goethe-Universität, FOR 412, Max-von-Laue-Str. 1, D-60438 Frankfurt(M), Germany — ²Institut für Mineralogie/Kristallographie, J. W. Goethe-Universität, FOR 412, Senckenberganlage 30, D-60054 Frankfurt(M), Germany

Our study focused on the structural and magnetic properties of two 1,1^′-bicoordinated oxalate-bridged Cu²⁺ spin chains, [Cu(µ-ox)-(H₂O)(4-apy)₂]_n (1) and [(pyOH)Cu(ox)-H₂O]_n (2). While in 1 all oxalate molecules are in the bis-monodentate configuration, compound 2 is built from two non-equivalent ox molecules which alternate in the bis-bidentate form along the chain. The Cu atoms of compound 1 are in a distorted square-pyramidal environment while those in compound 2 are in a distorted octahedral configuration. Magnetic measurements reveal the behavior of a uniform Heisenberg spin chain with a small antiferromagnetic (AF) exchange coupling constant of J ≈3K for 1, consistent with [1], and that of a dimer system with predominant AF intradimer interaction of J ≈403K and only weak interdimer couplings for 2. The nature and magnitude of the magnetic coupling through the oxalate bridges in 1 and 2 will be discussed in the light of available structural data.

[1] O. Castillo et al., Inorg. Chem. 39, 6142 (2000).