Core-shell structure Au@Fe3O4 nanoparticles was synthesized via a thermal decomposition method, evidencing through interplanar atomic distances of ~ 0.23 nm and ~ 0.48 nm finding in the center and the shell of the particles, matching to the (1 1 1) Au and (1 1 1) magnetite planes, respectively. The nanocomposite has an average diameter of the core of ~ 10.5 nm and a thickness of the shell of ~1.85 nm, accessed by TEM. X-ray diffraction carried out on the sample shows the crystal structure of fcc Au and fcc Fe3O4 without a spurious crystalline phase. Besides, Rietveld refinement displays an outer diameter of ~ 8.1 and ~ 12.3 for the core and shell, respectively, the latter using the Scherrer constant of 0.9 and 1.43, respectively. The UV–vis characterization result shows a surface plasmon resonance spectra of Au@Fe3O4 nanoparticles at ~ 540 nm, which advise a successful core–shell coupling of Au and the Fe3O4. Finally, the magnetic response displays a system with a superparamagnetic state at room temperature and with a distribution of blocking temperatures associated with the enhanced surface contribution related to the hollow magnetite structure's inner and outer surface. From the mean TB, the effective magnetic anisotropy Keff1.7×104 J/m3 was obtained, which is in agreement with the expected for the magnetite phase.
Bibliographical noteFunding Information:
The authors acknowledges the partial support of the the Agencies: Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq), Coordena??o de Aperfei?oamento de Pessoal de Ensino Superior (CAPES). F.F.H Arag?n acknowledges the support provided by the UNSA-Invetiga through the international impact researcher visit program (grant no III-22-2019-UNSA)
The authors acknowledges the partial support of the the Agencies: Conselho Nacional de Desenvolvimento Científico e Tecnológico ( CNPq ), Coordenação de Aperfeiçoamento de Pessoal de Ensino Superior ( CAPES ). F.F.H Aragón acknowledges the support provided by the UNSA -Invetiga through the international impact researcher visit program (grant no III-22-2019-UNSA )
© 2021 Elsevier B.V.
- Core-shell nanoparticles
- Effective magnetic anisotropy
- Surface plasmon resonance