EPR and magnetization studies on single crystals of a heterometallic (CuII and CrIII) complex: Zero-field splitting determination

Magnetic properties of single crystals of the heterometallic complex [Cu(bpy)(3)](2)[Cr(C2O4)(3)]NO3 center dot 9H(2)O (bpy = 2,2'-bipyridine) have been investigated. From the recorded EPR spectra, the spin-Hamiltonian parameters have been determined. The magnetization measurements have shown magnetic anisotropy at low temperatures, which has been analysed as a result of the zero-field splitting of the Cr-III ion. By fitting the exactly derived magnetization expression to the measured magnetization data, the axial zero-field splitting parameter, D, has been calculated. Comparing to the EPR measurements, it has been confirmed that D can be determined from the measurements of the macroscopic magnetization on the single crystals. (C) 2008 Elsevier Masson SAS. All rights reserved.