RE-doped Fe3O4 (RE = Eu, Gd, Er) nanoparticles for nanothermometry
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2019
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ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 64th
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Temperature affects every physical system, chemical reaction, and biological
process. A new method, magnetic nanothermometry, is being explored
to measure temperature throughout a volume. This method uses large changes in magnetization as function of temperature, which cannot be obtained with current magnetic nano-objects (MNO). To get a large magnetization
change we have examined the magnetic properties of RE-doped Fe3O4
(RE = Eu, Gd, Er) MNO. Samples were synthesized by co-precipitation.
For the doped material, RE+3 were chosen in order to replace the Fe+3 in
the (Fe+2)(Fe+3)2O4 structure. Structural characterization was performed by
X-ray diffraction and transmission electron microscopy. Hyperfine interaction
parameters as a function of temperature (300 K to 873 K) were obtained
by perturbed angular g-g correlation (PAC) spectroscopy using 111In(111Cd)
as probe nuclei. To fit the PAC spectra, the 111Cd probes were considered to
occupy three sites: tetrahedral, octahedral, and a third site where the probes
are located at the nanoparticle surface [1]. The hyperfine magnetic field Bhf
was calculated using the Larmor equation, and its behavior as a function
of temperature follows a Brillouin-type transition. For example, the Curie
temperature (TC) obtained for 5% Er-doped was approx. 846 K (FIG. 1),
which is higher than the expected TC for pure Fe3O4 (approx. 722 K) [2].
Magnetization as a function of temperature shows a 70 % change in magnetization
around 100 K for Er-doped Fe3O4 (FIG.2), which is an improvement
in temperature on pure Fe3O4 (below 50 K) [3]. Current work is focused on
correlating the temperature range in which the magnetization change occurs
and determining if it depends on the dopant element.
Como referenciar
CORREA, E.; BOSCH-SANTOS, B.; SALES, T.; CABRERA-PASCA, G.; CORREA, B.S.; NETO, O.F.; CARBONARI, A.W.; OLESHKO, V.; DENNIS, C. RE-doped Fe3O4 (RE = Eu, Gd, Er) nanoparticles for nanothermometry. In: ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 64th, November 4-8, 2019, Las Vegas, Nevada, USA. Abstract... p. 90-90. Disponível em: http://repositorio.ipen.br/handle/123456789/31536. Acesso em: 01 Mar 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.