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Abstract
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This work provides a set of structural, morphological, and magnetic results for the CoFe2-xAlxO4 (x = 0.00, 0.25, 0.50, 0.75, 1.00 at %) ferrite nanoparticles synthesized by the hydrothermal route. X-ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Spectroscopy (EDAX), High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED) microscopy and Fourier-Transform Infrared Microscopy (FTIR) were used to characterize the structural and morphological features of the prepared magnetic nanoparticles. Rietveld refinement carried out by the Material Analyses Using Diffraction (MAUD) software confirmed the formation of a single-phase spinel structure with no trace of impurity phase. FESEM micrographs showed the appearance of the ferrite nanoparticles with a size distribution in agreement with the data reported by XRD. HRTEM analyses showed the formation of cubic-shaped nanoparticles with dimensions near to the data extracted from XRD. The formation of spinel structure was approved by the FTIR spectra. The magnetic measurements through VSM analysis showed that the incorporation of Al3+ cations into the cobalt ferrite lattices decreases the values of saturation magnetization from about 69 emu/g to near 26 emu/g, which was attributed to the none-magnetic nature of Al3+ cations. The values of the coercive field, on the other hand, indicate a fluctuating trend as a function of Al3+ doping. The coercivity behavior was mainly affected by cation distribution, the variation of anisotropy constant, and the size of crystallites. All the obtained data showed that the magnetic ferrite nanoparticles could be synthesized successfully through the hydrothermal method as a technique that has not been used previously to prepare Co–Al ferrite nanoparticles.
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