Investigação das propriedades magnetoelásticas da ferrita de níquel : análise teórico-experimental

• Ano de defesa: 2018
• Autor(a) principal: Afonso, Ricardo
• Orientador(a): Gualdi, Alexandre José
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• Palavras-chave em Português: Ferrita de níquel; Teoria do funcional da densidade; Propriedades magnetoelásticas; Magnetostricção; Propriedades elásticas
• Palavras-chave em Inglês: Magnetostricition; Density functional theory; Nickel ferrites; Elastic properties
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/9719

In this dissertation, we investigate the magnetoelastic properties of nickel ferrite compared to the pure metal nickel, either by ab-initio calculation or through experiments using the capactive cell technique. The first step of our approach is to establish the convergence criteria on density functional theory (DFT). This also required us to benchmark our method by using other materials such as pure Fe, Co and diamond. The first step of our study is to explore not only the approach of DFT but also its capacity to describe other properties. Since all the electronic structures of theses material have been suitably reported, the second step of our calculation demonstrates how close to the experimental data DFT may result the elastic constants. The results has shown reasonably error to the actual values. On the third moment, our investigation resides to find the magnetostriction coefficient through DFT, which met in accordance with the experiments we carried out using the capacitance technique.