Effect of Zn Substitution on the Magnetic Properties of Cobalt Ferrite Nano Particles Prepared Via Sol-Gel Route

Sonal Singhal,Tsering Namgyal,Kailash Chandra,S. Bansal

doi:10.4236/jemaa.2010.26049

Abstract

Zinc substituted cobalt ferrite nanoparticles (CoxZn1-xFe2O4, with x = 0.0, 0.2, 0.4, 0.8 and 1.0) were prepared via sol-gel route and the effect of zinc concentration on saturation magnetization and lattice parameter were investigated. The particle sizes of the as obtained samples were found to be ~10 nm which increases upto ~92 nm on annealing at 1000oC. The frequency bands near 564-588 cm-1 and 425-442 cm-1 are assigned to the tetrahedral and octahedral clusters which confirm the presence of M-O stretching band in ferrites. The unit cell parameter ‘a’ increases linearly with increasing concentration of zinc due to larger ionic radii of Zn2+ ion . It was found that this substitution allows tunable changes in the magnetic properties of cobalt ferrite. Interestingly, saturation magnetization first increases upto x = 0.4 and then decreases for higher Zn substitution, thus tunable changes in magnetic properties of cobalt ferrite are possible. Source of such behaviour could be the variation of exchange interaction between the tetrahedral and the octahedral sites.

Highlights

Nanocrystalline ferrites are currently the subject of interest because of its wide application in industrial as well as re- search areas
An interesting example is that of CoFe2O4 which has got some peculiar properties like high saturation magnetization (Ms), high coercivity (Hc) and large anisotropy [2]
The authors suggested that the vibrational mode of tetrahedral clusters is higher as compared to that of octahedral clusters, which is attributed to the shorter bond length of tetrahedral clusters

Summary

Introduction

Nanocrystalline ferrites are currently the subject of interest because of its wide application in industrial as well as re- search areas. Dey and Ghose prepared Co0.2Zn0.8 Fe2O4 by co-precipitation method and found decrease in magnetization with increasing particle size [5]. Arulmurugan et al [6] suggested that substitution of Co2+ with Zn2+ lead to improved magnetic properties of nanocrystalline ferrites They observed a decreasing behavior of saturation magnetization and the particle size of the Co-Zn substituted ferrite nanoparticles with increasing Zn concentration. Effect of Zn Substitution on the Magnetic Properties of Cobalt Ferrite Nano Particles Prepared Via Sol-Gel Route 377 a measured frequency range but vary with sintering temperature. The present work deals with the synthesis of nano particles of zinc substituted cobalt ferrite (CoxZn1-xFe2O4 where x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) via sol-gel method and characterized using infrared spectroscopy (IR), transmission electron microscope (TEM), X-ray diffractometry (XRD) and magnetic measurements. This work is an attempt to investigate the magnetic properties of zinc substituted cobalt ferrites

Experimental

FT-IR Characterization

X-Ray Diffraction Studies

Magnetic Measurements

Conclusions