Magnetic properties, .sup.57./sup.Fe Mössbauer spectroscopy and .sup.1./sup.H NMR relaxometry of ε-Fe.sub.2-x./sub.Ga.sub.x./sub.O.sub.3./sub. nanoparticles: The effect of gallium doping on magnetic and MRI performance

0541750 - FZÚ 2022 RIV NL eng J - Článek v odborném periodiku
Kubíčková, Lenka - Kaman, Ondřej - Veverka, Pavel - Herynek, V. - Brázda, Petr - Bernášek, K. - Veverka, M. - Kohout, J.
Magnetic properties, ⁵⁷Fe Mössbauer spectroscopy and ¹H NMR relaxometry of ε-Fe_2-xGa_xO₃ nanoparticles: The effect of gallium doping on magnetic and MRI performance.
Journal of Alloys and Compounds. Roč. 856, Mar (2021), č. článku 158187. ISSN 0925-8388. E-ISSN 1873-4669
Grant CEP: GA MŠMT(CZ) EF16_019/0000760; GA ČR GA19-02584S; GA MŠMT(CZ) LM2018096
Grant ostatní: OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Institucionální podpora: RVO:68378271
Klíčová slova: epsilon ferric oxide * core-shell nanoparticles * hyperfine interactions * ¹H relaxometry * ultra-high-field MRI
Obor OECD: Nano-materials (production and properties)
Impakt faktor: 6.371, rok: 2021
Způsob publikování: Omezený přístup
https://doi.org/10.1016/j.jallcom.2020.158187

Magnetic nanoparticles of ε-Fe1.76Ga0.24O3 were prepared by thermal treatment of a mesoporous silica matrix impregnated with nitrates. The chosen Ga-doping enhanced magnetization and suppressed the low-temperature spin-reorientation transition typical for ε-Fe2O3. Despite the small mean size of 11 nm, the nanoparticles were in the blocked state over the whole temperature range under study, unlike standard superparamagnetic contrast agents based on other iron oxides or ferrites. The role of Ga-doping in local magnetic properties of the epsilon polymorph of ferric oxide was probed by 57Fe Mössbauer spectroscopy. The particles were further coated with silica and their performance in MRI was tested both in relaxometry and ultra-high-field imaging. The obtained dependences of relaxivity on temperature and thickness of the coating were placed in the context of relevant theoretical models of particle-induced relaxation – motional averaging and static dephasing regimes.
Trvalý link: http://hdl.handle.net/11104/0319282