Laser Investigations of Stored Metal Cluster Ions

The Mössbauer characterization of nanosized iron oxides is based on the dependence of the magnetic relaxation time on several parameters. Because the contributions of the magnetic anisotropy and of the particle volume cannot be separated, the knowledge of properties other than hyperfine by the use of several techniques is needed to achieve a full understanding of the studied system. In this work, after a brief review of the difference between bulk and nanostuctured magnetism, we show how Mössbauer spectroscopy, complemented by other techniques, applied to nanosized systems of maghemite and hematite, yields a good characterization of the solids and of the interparticle interactions. In the case of hematite we also show that more work is needed to identify in depth the parameters that determine the Morin transition.