Banca de DEFESA: IRIELSON CARNEIRO DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : IRIELSON CARNEIRO DE LIMA
DATA : 12/01/2018
HORA: 09:00
LOCAL: Sala 3F1
TÍTULO:

STUDY OF THE MAGNETIC PROPERTIES OF THE MIXED OXIDE OF IRON AND MANGANESE III

PALAVRAS-CHAVES:

Multiferroic, combustion, superparamagnetic

PÁGINAS: 59
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Inorgânica
ESPECIALIDADE: Determinação de Estrutura de Compostos Inorgânicos
RESUMO:

The continued and growing demand for high-performance, more versatile and miniaturized electronic devices has increased interest in the study and development of new materials. The multiferroic (magnetoelectrics, magnetoelastoelectrics, and ferroelectric-ferroelectric) has emerged as of great interest to associate two or more ferroic properties in the same material. In this work the mixed perovskite of iron and manganese (MnFeO₃) was synthesized by the combustion method, sintered at different temperatures (500 ° C, 750 ° and 900 ° C) and characterized by X-ray diffraction associated with the Rietveld method (DRX-Rietveld ) and X-Ray Fluorescence (FRX), while its magnetic properties were studied by Vibrating Sample Magnometry (VSM) and Electronic Paramagnetic Resonance (EPR).

Analysis of the DRX-Rietiveld spectra showed that in the sample sinteerized at 500 ° formation of oxides was formed while only 64% of the material was transformed into FeMnO3 of cubic structure, whereas in the samples sintered at 750 and 900 ° the formation almost that absolute of  FeMnO₃ with a small excess of iron oxide III, attributed to an experimental error. The X-ray fluorescence confirms the XRD information, showing the percentages of oxides formed.

Paramagnetism was investigated by EPR analysis and showed a wide signal in the region of 0.3 tesla, the calculation of the factor g gave 2.043 which is close to the theoretical value for a free electron confirming the paramagnetism. The magnetization curve as a function of the applied field (M x H) obtained by the Vsm technique, shows values for superparamagnetic material.

MEMBROS DA BANCA:
Presidente - 350633 - ADEMIR OLIVEIRA DA SILVA
Externo à Instituição - JARLEY FAGNER SILVA DO NASCIMENTO - IFRN
Interno - 7350310 - MARIA DE FATIMA VITORIA DE MOURA