Heat Treatment Effect on the Structural and Magnetic
Properties of Magnesium Ferrite Nanoparticles
C. Murugesan and G. Chandrasekaran
Department of Physics, Pondicherry University, R. Venkataraman Nagar, Kalapet, Pondicherry-605014, India
*
Corresponding author’s e-mail:chandgc@gmail.com
Abstract
Magnesium ferrite nanoparticles have been prepared
using sol-gel auto combustion method. The thermal studies
indicate that the decomposition of metal nitrates and fuel
completed within 475oC. In order to investigate the effect
of heat treatment on the structural and magnetic
properties, the prepared sample annealed at 500oC, 600oC,
700oC, 800oC and 900oC. X-ray diffraction (XRD) pattern
of as-prepared sample shows single phase spinel structure;
whereas the samples annealed at 500-700oC shows the
presence of α-Fe2O3 and 900oC annealed sample is free
from α-Fe2O3. Magnetic properties are measured using
vibrating sample magnetometer (VSM), the value of
saturation magnetization increasing with increasing
annealing temperature except for 500oC annealed
MgFe2O4 nanoparticles.
room temperature. The obtained loops shown in Fig.1
confirm soft ferrite nature of the prepared samples. The
value of saturation magnetization is increasing from
15.75 - 33.76 emu/g with annealing temperature except
for 500oC annealed sample.
Keywords: Spinel ferrites, annealing, combustion, crystallite
size, saturation magnetization.
Introduction
Ferrites have been attracted special attention due to
good magnetic properties as well as high electrical
resistivity. Spinel ferrites with general formula AFe2O4
(A-divalent metal ion) have found their important
applications in hyperthermia, information storage
systems, microwave devices, magnetic recording media,
electronic industries and humidity sensors [1].
Magnesium ferrite is one of the important spinel widely
used for technological applications such as high-density
magnetic recording, hyperthermia, and sensor. It was
reported that MgFe2O4 particles have relatively high
heat generation compared with other ferrites for
magnetic hyperthermia [2]. Therefore, it seems that
MgFe2O4 nanoparticles with a precise size control have
great capability for magnetic hyperthermia. Therefore
the present study is aimed at examining the effect of
heat treatment on the structural and magnetic properties
of MgFe2O4 nanoparticles synthesized using sol-gel
auto combustion method.
XRD Analysis
The crystallite size was calculated using Scherrer’s
equation, the average size of the crystallites increases
from 28 to 46 nm when annealing temperature
increases.
Magnetic Study:
Magnetic properties of the magnesium ferrite are
measured by tracing the magnetic hysteresis loop at
Figure1. Hysteresis curve of MgFe2O4 nanoparticles
annealed at different temperature.
These observed structural and magnetic properties
evidently bring out the direct impact of annealing
temperature on magnetic properties of magnesium
ferrite nanoparticles.
Acknowledgment
The authors thank the Central Instrumentation Facility,
Pondicherry University. C. Murugesan thanks UGC for
the financial assistance in the form of Rajiv Gandhi
National Fellowship (RGNF).
References
A. Goldman, Modern Ferrite Technology, Marcel
Dekker, New York, 1993.
[2] T. Maehara, K. Konishi, T. Kamimori, H. Aono, H.
Hirazawa, T. Naohara, S. Nomura, H. Kikkawa,
Y.Watanabe and K. Kawachi, “Selection of ferrite
powder for thermal coagulation therapy with alternating
magnetic field” J. Mater. Sci. 40 (2005) 135.