Synthesis and Study of Aluminum Substituted Copper Nickel Spinel Nano Ferrites

Abstract

This thesis work is based upon a series of Aluminum substituted CuNi-ferrite (Cu0.5Ni 0.5AlxFe2-xO4-) ferrite nanoparticles synthesized by chemical co- precipitation method with optimum synthesis conditions such as pH, reaction time and temperature. Characterization techniques such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), DC electrical resistivity and dielectric properties were incorporated for their study. From the analysis of the X-ray diffraction pattern it is confirmed that all the samples have single phase spinel structure. The lattice constant value decreases from 8.3527A°~ 8.3307A as the Al+3concentration increases from x=0.0 to x=0.5 respectively. The obtained values of crystallite sizes remain within the range of (9-46 ± 3 nm). The average particle size obtained from Scanning Electron Microscopy was 37.30 nm approximately for sample at x=0.0 and 33.28 nm at x= 0.5 which was closely an agreement to XRD measured value for particle size. The nanosize ferrite particles were spherical in shape having uniform distribution. From the FTIR measurements, two fundamental absorption bands were observed and assigned to the vibration of tetrahedral and octahedral sites. DC electrical resistivity shows an increase from 5.52 x 106 to 16.5 x 106 Ω cm as the Al3+ concentration increases from 0.00 to 0.50 respectively. The variation of dielectric constant, dielectric loss and tangent loss factor for all the samples have been studied as a function of frequency in the range 1MHz to 1000MHz at room temperature. The dielectric constant, dielectric loss and tangent loss factor varies with increasing Al3+ concentration between 5 to 8, 0.18 to 0.30 and 0.04 to 0.03 respectively at 1000 MHz. The drift mobility has been calculated for all the samples from the temperature dependent DC electrical resistivity measurements. It varies between 1.75 x 10-11 to 6.72 x 10-11 as Al3+ concentration increases from 0.00 to 0.50 respectively.