Papers by Author: S. Marutha Senthil

Abstract: The nano crystalline nickel-cobalt ferrite using albumen (egg white) is synthesized by thermal evaporation method and its dielectric behaviour is analyzed for different annealing temperatures. The dielectric property of the sample is measured using impedance analyzer in the frequency range 1-100 MHz. The variation of dielectric constant and dissipation factor under different frequency for the samples at different annealing temperature are analyzed. A steady dielectric constant is observed for the sample annealed at 500°C. The dielectric constant obtained for this sample is low and it is in the range of 18.9 to 6.9 for different frequencies. This low value of dielectric constant shows the less interfacial polarization due to high resistivity which may be to the presence of a few Fe2+ ions. It is observed that the dispersion in dielectric constant by varying the annealing temperature is producing an intended result. The presence of constituent phases in Ni1-xCoxFe2O4 is confirmed by X-Ray Diffraction. The particle size for Ni1-xCoxFe2O4 obtained from Scherrer equation is found to be is 30nm. The morphology, particle size and percentage composition of elements are measured by employing Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis spectrum (EDX).

Abstract: An attempt has been made to synthesize Ni1-xCoxFe2O4 by a simple technique of thermal evaporation with the help of egg white. The use of egg white (ovalbumin) in the synthesis process mainly helps to shape the particle during the reaction. The X-ray diffraction patterns reveal that the synthesized Ni1-XCoxFe2O4 ferrites are in nanocrystalline phase. The transmission electron microscopy observation confirmed that the average particle size of Ni1-xCoxFe2O4 has been varied from 7 nm to 30 nm. EDX spectrum gives account of the percentage composition of the products such as nickel, cobalt, Fe and O. Vibrating Samples Magnetometer (VSM) have been sued to study the saturation magnetization for variation of Ni substitution over CoFe2O4 and the influence of particle size in magnetic properties. Its analysis is based on the aspect of variation in coercivity with temperature. The FTIR spectra of the sample in the range 400 – 4000 cm-1 reveals the common feature of ferrites like high frequency band to the tetrahedral and low frequency band to the octahedral stretching vibrations.