Systematic studies of the magnetic properties of magnetic nanoparticles from FeraSpin R and the FeraSpin Series with respect to their suitability as tracers for magnetic particle imaging are presented. Magnetic particle spectroscopy measurements indicate that FeraSpin R exhibits a harmonic spectrum very similar to that of Resovist, whereas FeraSpin L, XL, and XXL show a 2.5-fold increase of harmonic amplitudes compared to FeraSpin R. To understand the differences between the various samples of the FeraSpin Series, representing size-selected, narrowly distributed particles of identical composition extracted from FeraSpin R, measurements of the ac susceptibility (ACS), magnetorelaxometry (MRX), and static M-H curves were performed on suspended and immobilized particle samples. ACS and MRX measurements on immobilized samples indicate a wide distribution of anisotropy energies despite the narrow distribution of hydrodynamic sizes. Static magnetization measurements show that all samples exhibit a bimodal distribution of magnetic moments: The fraction of larger moments corresponds to the contribution from the overall particle core, whereas the smaller is attributed to the contribution from the crystallites comprising the core.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering