Synthesis and Structural Properties of Bismuth Doped Cobalt Nanoferrites Prepared by Sol-Gel Combustion Method

Naraavula Suresh Kumar,Katrapally Vijaya Kumar

doi:10.4236/wjnse.2015.54016

Abstract

A series of Bismuth doped Cobalt nanoferrites of chemical composition CoBixFe2-xO4 (where x = 0.00, 0.05, 0.10, 0.15, 0.20 & 0.25) were prepared by sol-gel combustion method and calcinated at 600℃. The structural and morphological studies were carried out by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive Spectroscopy (EDS) and Fourier Transform Infrared (FT-IR) spectra showing the single phase spinal structure. The X-ray diffraction (XRD) analysis confirmed a single phase fcc crystal. The crystallite size of all the compositions was calculated using Debye-Scherrer equation and found in the range of 17 to 26 nm. The lattice parameters were found to be decreased as Bi3+ ion doping increases. The surface morphology was studied by Scanning Electron Microscope (SEM) and particle size was confirmed by Transmission Electron Microscopy (TEM). The EDS plots revealed existence of no extra peaks other than constituents of the taken up composition. The Fourier Transform Infrared (FT-IR) studies were made in the frequency range 350 - 900 cm-1 and observed two strong absorption peaks. The frequency band is found at 596 cm-1 where as the lower frequency band at 393 cm-1. It is clearly noticed that the two prominent absorption bands were slightly shifted towards higher frequency side with the increase of Bi3+ ion concentration.

Highlights

In recent years the research on metal nanoferrites has been the subject of much interest due to their unusual structural, magnetic, dielectric and electrical properties
The infrared spectra of synthesized powders were recorded by SHIMADZU Fourier Transform Infrared Spectrophotometer (FT-IR), Model P/N-206-73500-38, in the range of 4000 to 250 cm−1 with a resolution of 4 cm−1, which reveals the formation of single phase cubic spinal structure
The XRD pattern matches with the (JCPDS-KDD) file number of (22-1086) and the corresponding reflections of peaks (220), (311), (400), (333), (440) were observed in X-ray diffraction pattern

Summary

Introduction

In recent years the research on metal nanoferrites has been the subject of much interest due to their unusual structural, magnetic, dielectric and electrical properties. In general the nano ferrite materials have high resistivity i.e., low electrical conductivity, moderate saturation magnetization, high coercivity, mechanical hardness and chemical stability [6]-[9]. Cobalt Ferrite (CoFe2O4) is a spinal structured ceramic oxide and well known hard magnetic material with high coercivity and moderate magnetisation. Bismuth Ferrite (BFO) is one of the most important single phase multi ferroic materials due to their high electrical resistivity, low magnetic and dielectric losses [12] [13]. It is reported that on substituting of bismuth in very small amount does not alter the spinal structure of Cobalt ferrite. In this paper we have reported the synthesis and structural characterisations of Bismuth doped Cobalt nonoferrites with the chemical composition CoBixFe2-xO4 (where x = 0.00 to 0.25)

Experimental

Raw Materials

Synthesis

Characterization

XRD Analysis