Magnetic behaviour of nanoparticles deviates from bulk materials not only due to finite size and surface effects, but also by the occurrence of new crystal structures (polymorphs) and metastable states, such as non-equilibrium cation distribution.
Magnetic nanoparticles of iron oxides and substituted variants, including their functional derivatives, have attracted significant interest due to promising capabilities for emerging diagnostic imaging methods (e.g. magnetic resonance imaging, magnetic particle imaging) and novel therapeutic interventions (e.g. magnetic hyperthermia, targeted drug delivery).
Since a comprehensive understanding of the complex link between composition, microstructure, magnetic properties, and relaxation characteristics is pivotal for the rational design of well-defined magnetic nanoparticle systems, we have advanced Mössbauer spectroscopic methods for a specific use in nanoparticle research and developed a magnetic particle spectrometer to evaluate critical attributes of magnetic nanoparticle suspensions.