Study of structure and magnetic properties of Ni–Zn ferrite nano-particles synthesized via co-precipitation and reverse micro-emulsion technique

M Abdullah Dar,R K Kotnala,Jyoti Shah,W A Siddiqui

doi:10.1007/s13204-013-0241-x

Abstract

Nano-crystalline Ni–Zn ferrites were synthesized by chemical co-precipitation and reverse micro-emulsion technique with an average crystallite size of 11 and 6 nm, respectively. The reverse micro-emulsion method has been found to be more appropriate for nano-ferrite synthesis as the produced particles are monodisperse and highly crystalline. Zero-field cooled and field cooled magnetization study under different magnetic fields and magnetic hysteresis loops at different temperatures have been performed. The non-saturated M–H loops, absence of hysteresis, and coercivity at room temperature are indicative of the presence of super paramagnetic and single-domain nano-particles for both the materials. In sample ‘a’, the blocking temperature (TB) has been observed to decrease from 255 to 120 K on increasing the magnetic field from 50 to 1,000 Oe, which can be attributed to the reduction of magneto crystalline anisotropy constant. The MS and coercivity were found to be higher for sample ‘a’ as compared with sample ‘b’ since surface effects are neglected on increasing the crystallite size.

Highlights

Nano-crystalline ferrites are materials of considerable interest because of their unique dielectric, magnetic, and optical properties, which make them appealing both from the scientific and technological points of view (Wang et al 1998; Abdullah Dar et al 2010)
We have reported the synthesis of nano-crystalline sized mixed ferrite system, namely Ni0.7Zn0.3Fe2O4, by chemical co-precipitation and reverse micro-emulsion method
X-ray diffraction pattern of Ni0.7Zn0.3Fe2O4 ferrite nanocrystals synthesized via chemical co-precipitation and reverse micro-emulsion technique are presented in Fig. 1a, b, respectively

Summary

Introduction

Nano-crystalline ferrites are materials of considerable interest because of their unique dielectric, magnetic, and optical properties, which make them appealing both from the scientific and technological points of view (Wang et al 1998; Abdullah Dar et al 2010). The study of magnetic behavior of ferrites has attracted considerable attention from past few decades, in particular because deviations from bulk behavior have been widely reported for particle sizes below about 100 nm range. Considerable attention has been paid on ferrites of different morphology and their shape- and sizedependent properties as well their corresponding applications were investigated Both the physical and chemical methods have been developed for the synthesis of ferrite nano-structures of various morphologies. We have reported the synthesis of nano-crystalline sized mixed ferrite system, namely Ni0.7Zn0.3Fe2O4, by chemical co-precipitation and reverse micro-emulsion method. Synthesis of Ni0.7Zn0.3Fe2O4 ferrite nano-crystals by reverse micro-emulsion method. Two reverse micro-emulsions were prepared for the synthesis of Ni0.7Zn0.3Fe2O4 ferrite nano-crystals, one containing the metal salts prepared by mixing stoichiometric amounts of 0.2 M Fe(NO3)3Á9H2O, 0.07 M Ni(NO3)2Á6H2O and 0.03 M Zn(NO3)2Á6H2O. In order to study the effect of applied magnetic field on the blocking temperature (TB) and on the magneto-crystalline anisotropy, ZFC–FC measurements were performed at two different magnetic fields (50 and 1,000 Oe)

Results and discussion

80 K 100 K 150 K 200 K 250 K 300 K

Conclusions