DENER PEREIRA SANTOS
Abstract:
In this master project were synthesized magnetic nanoparticles (NPs) formed by the transition metal oxides ZnFe2O4, CoFe2O4 and MnFe2O4. To understand the electronic structure of the NPs, were used the techniques X-Ray Fluorescence Spectroscopy (XRF) and Photoelectron Spectroscopy (XPS). To understand the crystallographic structure, were used the techniques X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The procedure used to synthesize the compounds was the Pechini method, using high purity metal salts, containing the following chemical elements: Zn, Co, Mn and Fe. The metal salts were mixed to the polymer (Polyvinylpyrrolidone) at specific concentrations, followed by stirring by 2 hours, then maintained in an oven at 80 ° C for 24 hours. To crystallize the NPs, the samples were calcined at different temperatures: 400 ° C, 500 ° C and 600 ° C for a period of 4 hours. The FRX technique suggested that after the chemical synthesis process, the concentrations of the metal ions were the same as those of ferrite compounds. The XRD technique confirmed the formation of Zn, Mn and Co ferrites with polycrystalline formation. Through the MET we can observe the average grain size, with diameters between 10 and 20 nm, with ideal size for biological applications. The XPS technique also confirms the formation of Zn, Mn and Co ferrites.
