Abstract
Abstract Nanocrystalline cobalt ferrite powder has been synthesised by citrate precursor and co-precipitation methods. Structural characterization of the samples has been carried out using powder X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscope (FE-SEM). Distribution of cations among the two interstitial sites (tetrahedral and octahedral sites) has been estimated by analysing the powder X-ray diffraction patterns by employing Rietveld refinement technique, and the results reveal the existence of samples as a mixed type spinel with cubic structure. It is observed that the distribution of cations and structural parameters are strongly dependent on synthesis method and annealing temperature. The vibrational modes of the octahedral and tetrahedral metal complex in the sample have been examined using FT-IR in the wave number range of 390 to 750 cm−1, and it shows an absorption band within this range, which confirms the spinel structure of the sample. The existence of constituents in the sample, i.e., Co, Fe and O has been authenticated using energy dispersive spectrum with the help of a FE-SEM.
Highlights
Magnetic nanoparticles of spinel ferrites are of great interest in fundamental science especially in addressing the relationship between magnetic properties and their crystal chemistry
Different sizes of nanocrystalline cobalt ferrites were successfully synthesised by the citrate precursor and coprecipitation methods
It has been observed that the crystallite size increases with the increase in annealing temperature, and the crystallite size can be controlled by controlling the annealing temperature
Summary
Magnetic nanoparticles of spinel ferrites are of great interest in fundamental science especially in addressing the relationship between magnetic properties and their crystal chemistry. Crystal chemistry shows how the chemical composition, internal structure, distribution of cations, and physical properties are linked together, and it gives a clear understanding of magnetic properties of spinel ferrite nanoparticle. M2+ and Fe3+ are the divalent and trivalent cations, respectively It crystallises in a facecentred cubic structure belonging to the space group Fd 3À m composed of large unit cells containing eight formula units [AB2O4]8, i.e. a total of 56 ions per unit cell. Eight tetrahedral (A sites) and 16 octahedral (B sites) sites are occupied by the divalent and trivalent technological applications at or above room temperature, such as data storage devices, magnetic sensors, actuators, targeted drug delivery, medical diagnosis, etc. The nanocrystalline cobalt ferrite is in infant stage to be used in technological applications
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