Banca de DEFESA: RAFAEL LEAL DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RAFAEL LEAL DA SILVA
DATA : 29/11/2018
HORA: 10:00
LOCAL: Auditório do DFTE
TÍTULO:

Synthesis and characterization of nanostructures of samarium doped ferrites and coated with polymers.

PALAVRAS-CHAVES:

Defesa Doutorado

PÁGINAS: 115
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
SUBÁREA: Física da Matéria Condensada
RESUMO:

This work was shown in the physical and characterization of nanoparticles magnetite and ferrite of cobalt doped with Sm: Fe 2.68Sm0.32O4 and CoFe (2-x) SmxO4 (x = 0.05, 0.10, 0.15 and 0.20). As magnetite nanoparticles were produced using the polyol method, where the polymer polyvinylpyrrolidone (PVP) was used for protection as nanoparticles of the oxidation. As nanoparticles of Sm-doped cobalt ferragens, they were constructed by the ionic rope reaction (ICR) method and covered by a chitosan matrix.
A crystal structure and magnetic properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy and DC magnetometry.
A magnetite sample has a print size distribution having a diameter of 5.2 nm. As the bees presented under the superparamagnetic effect of 4 × 105 J / m3 at 5 K. In a constant environment, the MH presented the has a single paramagnetic component, while the 5 K is a saturation magnetization of 18.9 emu / ha MH curve , field cooling (FC) has a displacement with a bias shift field of ~ 110 Oe. The benefits are discussed in terms of spatial distribution of actions, as determined by Mössbauer spectroscopy. Immunization of magnetocrystalline anisotropy.
The cobalt silver samples are coated by the chitosan biopolymer, with a variable variation of the Sm-ion concentration dependent sizes, ranging from 9.49 nm to 5.62 nm. The coercive field values, saturation magnetization and anisotropy were subjected to structural changes with doping. A theological dose was made taking into account the form of distribution of particles, blocked and superparamagnetic. The mega-sounds spectrum was when performance was used in three sixths in each of the crystallographic groups, at room temperature and at 12 K. The results were calculated in relation to the random distribution of Smenoe A and B levels. were for applications of an AC magnetic field of 70.5 kHz and intensity of 200 Oe. The value was maximum for the sampling of a series of 12.09 W / g, which aims to use hyperthermia.

MEMBROS DA BANCA:
Externo à Instituição - GUSTAVO DE OLIVEIRA GURGEL REBOUCAS - UFERSA
Externo à Instituição - JOSE ALZAMIR PEREIRA DA COSTA - UERN
Presidente - 350830 - JOSE HUMBERTO DE ARAUJO
Interno - 1674707 - MARCO ANTONIO MORALES TORRES
Externo à Instituição - RODOLFO BEZERRA DA SILVA - UERN