| Texto completo | |
| Autor(es): |
Orozco-Henao, Juan M.
;
Almeida, Adriele A.
;
Fabris, Fernando
;
Floridia Addato, Maria A.
;
Fonticelli, Mariano H.
;
Muraca, Diego
;
Lavorato, Gabriel C.
Número total de Autores: 7
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Nano Letters; v. 25, n. 33, p. 8-pg., 2025-08-08. |
| Resumo | |
Spinel ferrite nanoparticles (NPs) with controlled composition, size, and morphology have offered a wide range of functional properties, but engineering nonhomogeneous composition profiles remains elusive. Here, we use Fe3O4/CoFe2O4 core/shell NPs as precursors to prepare compositionally graded NPs via controlled interfacial diffusion of metal cations. Electron-microscopy-based elemental mapping reveals that thermal annealing above 200 degrees C in an oxygen-rich atmosphere transforms the initially sharp core/shell interface into a compositionally graded spinel structure with a Co-rich outer layer. This cation redistribution results in pronounced changes in the magnetic properties, including a remarkable increase in coercivity and high-field susceptibility. Enhancement in the effective anisotropy is quantitatively described by modeling the time-dependent Co diffusion, enabling estimation of the cation diffusivity. These findings demonstrate a robust strategy for preparing anisotropy-graded spinel ferrite NPs, offering a broadly applicable approach to tailoring the properties of complex metal oxide nanostructures. (AU) | |
| Processo FAPESP: | 21/13592-0 - Magnetolipossomas para liberação controlada e remota de fármacos ativados por meio de campo magnético alternado |
| Beneficiário: | Adriele Aparecida de Almeida |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 22/16460-0 - Ferrofluidos para aplicações em escoamento de fluidos viscosos |
| Beneficiário: | Diego Muraca |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 19/13678-1 - Propriedades magnéticas em estruturas nanoconfinadas: nanopartículas metálicas e isolantes dopadas com terras-raras produzidas por Laser Ablation e síntese química. |
| Beneficiário: | Fernando Fabris |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |