Synthesis, structure and magnetic properties of the Lu2O3–CoO mixed system

Polycrystalline samples of the cubic Lu2−xCoxO3 solid solutions (x = 0.1, 0.3, 0.5) were prepared and analyzed by the XRD Raman spectroscopy and magnetic susceptibility measurements. The samples crystallize in the space group Ia-3 with a byxbyite structure type. The structure refinement have shown that Co3+ is preferentially distributed in C3i sites in Lu2O3 host. Replacing Lu3+ by Co3+ introduces slight changes in the atomic coordinates leading to decrease of the mean cation–anion distances. The ability of Raman spectroscopy to detect changes in local co-ordination is utilized. The susceptibility data was analyzed within 2–50 K range according to the second-order perturbation (Van Vleck equation). The differences in χ−1(T) are mainly caused by the difference in the crystal field strength and less by exchange interaction. The concentration dependence of the magnetic susceptibility is caused by the concentration dependence of effective crystal field.