Abstract of Publication No. 343
O. Waldmann, J. Schülein, R. Koch, P. Müller, I. Bernt, R. W. Saalfrank, H. P.
Andres, H. U. Güdel and P. Allenspach
The magnetic anisotropy of the two cyclic hexanuclear Fe(III) clusters
L = N(CH2CH2O)3, was investigated. Based on a
spin Hamiltonian formalism, the magnetic anisotropy was calculated exactly to
first order, i.e., in the strong exchange limit, using Bloch's perturbational
approach and irreducible tensor operator techniques. Experimentally, the
magnetic anisotropy was investigated by magnetic susceptibility and high-field
torque magnetometry of single crystals as well as inelastic neutron scattering.
It is demonstrated that torque magnetometry provides a valuable tool for the
study of magnetic anisotropy in spin cluster complexes. The experimental data
could be accurately reproduced by the calculations, and the different methods
yield consistent values for the coupling constants and zero-field-splitting
parameters. Both the anisotropy and the exchange interaction parameter are found
to increase with increasing Fe-O-Fe angle.