Speaker
Description
Magnetic nanoparticles (MNPs) and their unique properties are of intense research interest. These nanoscopic materials exhibit complex magnetic behavior, which is essential in the proposed applications, ranging from spintronics and catalysis to biomedicine, where they found their usage as contrast agents in imaging techniques or innovative cancer treatment (hyperthermia) [1]. This led to a substantial investigation, particularly aimed at iron oxide MNPs. However, we present a novel candidate, the $\varepsilon$-Fe$_3$N, possessing unprecedented magnetic properties in bulk form, surpassing classical MNPs of iron oxides. In this contribution, we will present a comprehensive characterization of passivated $\varepsilon$-Fe$_3$N MNPs with a mean particle diameter of $17.2(2)$ nm. The complex magnetic nature of this material was disentangled by probing magnetic scattering fluctuations using the magnetic small-angle scattering with incident beam polarization at the D$33$ instrument at ILL [3]. In summary, we will reveal the radial distribution of nuclear scattering density, expose the magnetic morphology of passivated $\varepsilon$-Fe$_3$N MNPs, unravel magnetization contributions from the magnetic core and shell, and ultimately discuss the resulting magnetic response of presented MNPs.
Acknowledgements
This work was supported by the Czech Science Foundation (22-10035K) and the AMULET project, co-funded by MŠMT and the EU (CZ. 02.01.01/00/22_008/0004558). We also acknowledge the Institut Laue-Langevin for beamtime and financial support.
References
[1] L. M. Bauer et al., “High-performance iron oxide nanoparticles for magnetic particle imaging – guided hyperthermia (hMPI),” Nanoscale, vol. 8, no. 24. Royal Society of Chemistry (RSC), pp. 12162–12169, 2016. https://doi.org/10.1039/c6nr01877g
[2] I. Dirba et al., “Evaluation of Fe-nitrides, -borides and -carbides for enhanced magnetic fluid hyperthermia with experimental study of α″-Fe16N2 and ϵ-Fe3N nanoparticles,” Journal of Physics D: Applied Physics, vol. 56, no. 2. IOP Publishing, p. 025001, Nov. 17, 2022. https://doi.org/10.1088/1361-6463/aca0a9
[3] S. Hricov et al., “Unmasking the Complex Core-Multishell Morphology of Magnetic Nanoparticles.” Institut Laue-Langevin (ILL), 2023. https://doi.org/10.5291/ILL-DATA.DIR-297
