Temperature and field dependences of transverse relaxivity of Co-Zn ferrite nanoparticles coated with silica: the role of magnetic properties and different regimes

0541752 - FZÚ 2022 RIV CH eng J - Journal Article
Veverka, Pavel - Kubíčková, Lenka - Jirák, Zdeněk - Herynek, V. - Veverka, Miroslav - Kaman, Ondřej
Temperature and field dependences of transverse relaxivity of Co-Zn ferrite nanoparticles coated with silica: the role of magnetic properties and different regimes.
Materials Chemistry and Physics. Roč. 260, Feb (2021), č. článku 124178. ISSN 0254-0584. E-ISSN 1879-3312
R&D Projects: GA MŠMT(CZ) EF16_019/0000760; GA ČR GA18-13323S
Grant - others:OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Institutional support: RVO:68378271
Keywords : magnetic nanoparticles * silica-coated particles * transverse relaxivity * motional averaging regime * static dephasing
OECD category: Nano-materials (production and properties)
Impact factor: 4.778, year: 2021
Method of publishing: Limited access
https://doi.org/10.1016/j.matchemphys.2020.124178

The transverse relaxivity r2 depends on multiple factors, most importantly on magnetic properties and the size of the particles, including both the size of magnetic cores and the effective size of whole particles present as individual entities in the suspension. The current study probes the transverse relaxivity of ferrimagnetic CoxZnyFe3-x-yO4 nanoparticles whose behavior varies from the blocked state, across the superparamagnetic regime to the vicinity of the paramagnetic state, while other parameters, namely the size of the magnetic cores (≈10 nm), the size of whole colloidally stable particles, and their geometry (≈30 nm-sized clusters of crystallites uniformly coated with ≈12 nm thick silica shell) are kept the same. Importantly, the field and temperature dependences of transverse relaxivity are discussed in relation to relevant theoretical models, i.e., motional averaging and static dephasing regimes.
Permanent Link: http://hdl.handle.net/11104/0319283