Investigation of the oxohalogenide Cu4Te5O12Cl4 with weakly coupled Cu(II) tetrahedra

Abstract

The crystal structure of the copper(II) tellurium(IV) oxochloride Cu${}_4$Te${}_5$O${}_{12}$Cl${}_4$ (Cu-45124) is composed of weakly coupled tetrahedral Cu clusters and shows crystallographic similarities with the intensively investigated compound Cu${}_2$Te${}_2$O${}_5$X${}_2$, with X~=~Cl, Br (Cu-2252). It differs from the latter by a larger separation of the tetrahedra within the crystallographic ab plane, that allows a more direct assignment of important inter-tetrahedra exchange paths and the existence of an inversion center. Magnetic susceptibility and specific heat evidence antiferromagnetic, frustrated correlations of the Cu spin moments and long range ordering with $T_c$=13.6 K. The entropy related to the transition is reduced due to quantum fluctuations. In Raman scattering a well structured low energy magnetic excitation is observed at energies of $\approx$50K (35cm${}^{-1})$. This energy scale is reduced as compared to Cu-2252.

11 pages, 9 figures, further information see http://www.peter-lemmens.de

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Cited by in corpus (5)

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• Spin-lozenge thermodynamics and magnetic excitations in Na${}_3$RuO${}_4$
• Series expansion analysis of a tetrahedral cluster spin chain
• Microscopic model for the novel frustrated Cu(II)-spin tetrahedron-based Cu4Te5O12X4 (X=Cl, Br) systems