Size dependence of the surface spin disorder and surface anisotropy constant in ferrite nanoparticles

0575070 - ÚMCH 2024 RIV GB eng J - Článek v odborném periodiku
Gerina, M. - Angotzi, M. S. - Mameli, V. - Gajdošová, Veronika - Rainer, D. N. - Dopita, M. - Steinke, N.-J. - Aurélio, D. - Vejpravová, J. - Zákutná, D.
Size dependence of the surface spin disorder and surface anisotropy constant in ferrite nanoparticles.
Nanoscale Advances. Roč. 5, č. 17 (2023), s. 4563-4570. ISSN 2516-0230. E-ISSN 2516-0230
Institucionální podpora: RVO:61389013
Klíčová slova: magnetic nanoparticles * core-shell * ferrite
Obor OECD: Polymer science
Impakt faktor: 4.7, rok: 2022
Způsob publikování: Open access
https://pubs.rsc.org/en/content/articlelanding/2023/NA/D3NA00266G

The magnetic properties of nanoscale magnets are greatly influenced by surface anisotropy. So far, its quantification is based on the examination of the blocking temperature shift within a series of nanoparticles of varying sizes. In this scenario, the surface anisotropy is assumed to be a particle size-independent quantity. However, there is no solid experimental proof to support this simplified picture. On the contrary, our work unravels the size-dependent magnetic morphology and surface anisotropy in highly uniform magnetic nanoparticles using small-angle polarized neutron scattering. We observed that the surface anisotropy constant does not depend on the nanoparticle's size in the range of 3–9 nm. Furthermore, our results demonstrate that the surface spins are less prone to polarization with increasing nanoparticle size. Our study thus proves the size dependence of the surface spin disorder and the surface anisotropy constant in fine nanomagnets. These findings open new routes in materials based on a controlled surface spin disorder, which is essential for future applications of nanomagnets in biomedicine and magnonics.
Trvalý link: https://hdl.handle.net/11104/0345370