TATIANE DA SILVA NASCIMENTO

TATIANE DA SILVA NASCIMENTO

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Synthesis and characterization of Fe3O4-HfO2 nanoparticles by magnetization and hyperfine interactions measurements
2020 - MATOS, IZABELA T.; SALES, TATIANE S.; CABRERA-PASCA, GABRIEL; BURIMOVA, ANASTASIA; SAXENA, RAJENDRA N.; PEREIRA, LUCIANO F.; OTUBO, LARISSA; CARBONARI, ARTUR W.
Nanoparticles (NPs) that combine biocompatibility and enhanced physical characteristics for biomedical applications are currently an area of intense scientific research. Hafnium oxide NPs is an innovative approach in the anticancer treatment by radiotherapy due to their low toxicity and enhancement of local dose in the tumor reducing the total radiation dose for the patient [1]. The combination of this amazing property with the excellent magnetic hyperthermia performance of Fe3O4 NPs can produce a promising nanomaterial for cancer therapy. In the present work, we have synthesized NPs samples of Fe3O4 doped with 10%Hf and HfO2 doped with 10% Fe by chemical procedures. The samples had their morphological, structural, and magnetic properties characterized by some results being displayed in Fig. 1. The crystal structure of the samples was characterized by X-ray Diffraction (XRD), whose results present a single phase. Transmission Electron Microscopy (TEM) images show spherical and hexagonal NPs with an average size of 12 nm as displayed in Fig. 2. The magnetic property was investigated by magnetization measurement. The results from the temperature dependence of ZFC-FC magnetization show a large peak in the ZFC curve corresponding to a broad distribution of blocking temperatures as shown in Fig. 1(b). Fortunately, when irradiated with neutrons in a research reactor, the nuclear reaction 180Hf(n,γ)181Hf yields the probe nucleus 181Hf(181Ta) used by the perturbed angular correlations (PAC) technique to measure hyperfine interactions. Both samples show electric quadrupole interaction characteristics of the HfO2 phase indicating that the Fe replaces Hf in HfO2 NPs, but rather than substituting Fe, Hf form HfO2 NPs diluted in Fe3O4 NPs. Moreover, a pure time-dependent magnetic dipole interaction below 300 K was observed for Fe3O4 NPs mixed with 10% of HfO2.
Annealing effect on the structural and local magnetic properties of nickel ferrite nanoparticles studied by hyperfine interaction measurements
2020 - RODRIGUES, PRISCILA S.; MATOS, IZABELA T.; SALES, TATIANE S.; BURIMOVA, ANASTASIA; CABRERA-PASCA, GABRIEL; PEREIRA, LUCIANO F.; SAXENA, RAJENDRA N.; OTUBO, LARISSA; CARBONARI, ARTUR W.
Nickel ferrite in the form of nanoparticles is a technologically important material that can be applied for the production of biosensors, catalysts, drug delivery, and magnetic resonance contrast agents. In this work NiFe O samples comprising spherical nanoparticles of ~6 nm in diameter have been synthesized via a thermal decomposition route. The quality control of the samples was carried out with conventional techniques including X-ray diffraction and transmission electron microscopy. Post-synthesis XRD pattern revealed textured spinel NiFe O . Local magnetic properties were examined with Time Differential Perturbed Angular Correlation (TDPAC) spectroscopy within the 12 - 773K temperature range with In( Cd) probe introduced into the samples at synthesis. Quasi-static magnetic properties were observed (including above room temperature), as expected due to the small time window of TDPAC. The TDPAC results shown in Fig. 1 were analyzed using a model with combined electric quadrupole and magnetic dipole interactions. An expressive dynamic interaction was observed upon heating after synthesis. A theoretical model based on the Brillouin function for different ionic moments was applied to study the evolution of the hyperfine magnetic field with temperature (see Fig. 1-2) and allowed to attribute the magnetic interaction to the probe location at Fe3+ site. Site occupancy and the interplay between magnetic and structural properties are discussed with respect to application perspectives.
The effect of Er doping on local structure of magnetite nanoparticles
2021 - RODRIGUES, PRISCILA S.; BURIMOVA, ANASTASIA; SALES, TATIANE S.N.; FILHO, ARNALDO A.M.; OTUBO, LARISSA; SAXENA, RAJENDRA N.; CARBONARI, ARTUR W.
In this work Fe3O4:Er nanoparticles (NPs) with the characteristic size of ~ 11 nm were synthesized via classic co-precipitation method. Electron microscopy and X-ray diffraction were employed to probe the morphology and structure of the samples. Results revealed that samples synthesized in the Fd-3mZ structure with lattice constant close to that of pure magnetite. 111In probe generator was incorporated at synthesis in order to map the evolution of hyperfine magnetic field with temperature using time differential perturbed angular correlation (TDPAC) spectroscopy. The TDPAC results are discussed in terms of the effect of Er dopant on the magnetic properties and local structure of the NPs.
Investigation of hyperfine interactions of multiferroic oxides Bi0.85La0.15FeO3 through perturbed angular correlation spectroscopy
2021 - MIRANDA FILHO, A.A.; SALES, T.S.N.; OTUBO, L.; CABRERA-PASCA, G.A.; CARBONARI, A.W.
Synthesis and characterization of Fe3O4-HfO2 nanoparticles by hyperfine interactions measurements
2021 - SALES, T.S.N.; BURIMOVA, A.; RODRIGUES, P.S.; MATOS, I.T.; CABRERA-PASCA, G.A.; SAXENA, R.N.; PEREIRA, L.F.D.; OTUBO, L.; CARBONARI, A.W.
Nanoparticles (NPs) that combine biocompatibility and enhanced physical characteristics for biomedical applications are currently an area of intense scientific research. Hafnium oxide NPs are an innovative approach in the anticancer treatment by radiotherapy due to their low toxicity and enhancement of local dose in the tumor reducing the total radiation dose for the patient. The combination of this property with the excellent magnetic hyperthermia performance of Fe3O4 NPs can produce a promising nanomaterial for cancer therapy. In this work, we attempted to synthesize nanoscale samples of HfO2 doped with nominal 10 at.% Fe, and Fe3O4 doped with Hf at 10 at.% level using simple chemical routes. The crystal structure of the samples was characterized by X-ray diffraction. The material was irradiated with neutrons in a research reactor, the nuclear reaction 180Hf(n, γ)181Hf yielding the probe nucleus 181Hf(181Ta) used in the perturbed angular correlations experiments to measure hyperfine interactions. Despite their immediate response to the external magnetic field, at local level both samples showed only electric quadrupole interaction typical of the monoclinic hafnia indicating that Fe replaces Hf in HfO2 NPs, but, rather than substituting Fe, Hf enters magnetite in the form of HfO2 clusters. Transmission Electron Microscopy was exploited to study the morphology of these complex systems, as well as to localize hafnia clusters and understand the nature of their coupling to Fe3O4 specks.