Detalhes bibliográficos
| Ano de defesa: |
2022 |
| Autor(a) principal: |
Maia, André de Oliveira Girão |
| Orientador(a): |
Não Informado pela instituição |
| Banca de defesa: |
Não Informado pela instituição |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Não Informado pela instituição
|
| Programa de Pós-Graduação: |
Não Informado pela instituição
|
| Departamento: |
Não Informado pela instituição
|
| País: |
Não Informado pela instituição
|
| Palavras-chave em Português: |
|
| Link de acesso: |
http://www.repositorio.ufc.br/handle/riufc/68690
|
Resumo: |
This work deals with the synthesis of superparamagnetic nanoparticles of cobalt ferrite and nickel ferrite, through the protein sol-gel method, which uses gelatin as an organic precursor, and a rapid thermal processing furnace that uses halogen lamps as a heat source. XRD, TEM, M × H, FC, ZFC and Mössbauer Spectroscopy measurements were performed to characterize the samples. Nanoparticles with an average size of 5-10 nm and microstrain of the order of 10-4-10-3 were obtained for cobalt ferrite and for nickel ferrite the average size was 6-12 nm and the microstrain of the order of 10-4-10-2. The increase in coercivity and remanence was observed with increasing nanoparticle size for both materials. Saturation magnetization decreased with particle size reduction due to the formation of a disordered layer on the surface. Mössbauer spectroscopy showed an increase in the amount of superparamagnetic nanoparticles for samples with smaller nanoparticles and with less dispersion. |
