Synthesis and study of cerium substituted cobalt nickel spinel nano ferrites

Abstract

A series of Cerium substituted Cobalt Nickel Ferrite nano particles with nominal composition Co0.5Ni0.5CexFe2-xO4 (where x=0.00, 0.05, 0.10, 0.15, 0.20) have been synthesized by chemical co-precipitation and sol–gel auto combustion techniques. Samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), dielectric properties and DC electrical resistivity. XRD confirmed the cubic spinel structure for both syntheses routs. The unit cell parameter increased by increasing Ce concentration from 8.359 Å to 8.372 Å for coprecipitation and from 8.353 Å to 8.367 Å for sol-gel while crystallite size decreased from 24 nm ±1 nm to 16 nm ±1 nm for co-precipitation and from 27 nm ±1 nm to 18 nm ±1 nm for sol-gel. Theoretical density increased from 5.335 g/cm3 to 5.692 g/cm3 for coprecipitation and from 5.347 g/cm3 to 5.366 g/cm3 for sol-gel. SEM results show presence of uniformly distributed and almost spherical in shape particles for both techniques. FTIR measurements confirm vibrations at tetrahedral and octahedral sites by two fundamental absorption bands υ1 around 600 cm-1 and υ2 around 400 cm-1 . DC electrical resistivity of x=0.00 sample is higher than Ce substituted ferrite samples and in the range of 108 Ω-cm at 373 K. Dielectric properties are studied from 100 Hz to 5 MHz as a function of frequnecy