Magnetization curves of Dy-N clusters

Magnetic properties of isolated Dy-N clusters are studied in a molecular be am performing Stern-Gerlach experiments. The magnetizations mu (z) of Dy-N, axe measured in dependence of the magnetic field strength B = 0-1.6 T and at nozzle temperatures T-n = 18 K and T-n = 300 K. At room temperature the magnetization augments linear with the field following a simple paramagneti c model. At T-n = 18 K the magnetization curves saturate at field strengths B greater than or equal to 0.8 T. To explain the magnetization process at low temperatures two models are discussed: A model for adiabatic magnetizat ion based on cluster rotation effects and a modified van-Vleck model.