VOL. 3, NO. 1, January 2013 ISSN 2225-7217
ARPN Journal of Science and Technology
©2011-2013. All rights reserved.
http://www.ejournalofscience.org
106
Magnetization and Magnetic Behavior of Ni
1-x
Cd
x
Fe
2
O
4
Ferrites
1
Sumon Kumar Nath,
2
M. Mahbubur Rahman,
3
S.S. Sikder,
4
M.A. Hakim,
5
S. Manjura Hoque
1,3
Department of Physics, Khulna University of Engineering Technology (KUET), Khulna 9203, Bangladesh.
2
Department of Physics, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh.
2
School of Engineering & Energy, Murdoch University, Murdoch, Western Australia 6150, Australia.
4,5
Materials Science Division, Atomic Energy Centre, Ramna, Dhaka 1000, Bangladesh.
ABSTRACT
This article describes the experimental investigation on the magnetization behavior of Ni
1-x
Cd
x
Fe
2
O
4
ferrites for x 0.0 &
0.8 prepared by conventional ceramic method. Magnetic properties have been measured as a function of field and
temperature using vibrating sample magnetometer and SQUID magnetometer. Saturation magnetization at 20 K increases
with Cd-content up to x = 0.5 and decreases thereafter. Neel’s two sublattice collinear model is applied for the initial rise
of the magnetization up to x 0.5 and beyond that three sublattices non-collinear model proposed by Yafet-Kittel are
predominant. This indicates the appearance of spin canting structure in Ni
1-x
Cd
x
Fe
2
O
4
ferrites with higher Cd-content.
Sample with x = 0.8 shows anomalous temperature dependent magnetic ordering on applied magnetic field. Low field (5
Oe) magnetization shows antiferromagnetic ordering while the ferromagnetic ordering has been found to be dominant with
the high field (1 T). That is the magnetic ordering of Ni
1-x
Cd
x
Fe
2
O
4
is dependent on the strength of applied field.
Keywords: Saturation magnetization, spin canting, magnetic ordering, ferromagnetic ordering, antiferromagnetic ordering.
1. INTRODUCTION
Ferrites have proved them commercially
important magnetic materials ranging from the very
ordinary radio sets to the complicated and exhaustive
hardware involved in computers. Ferrites are extensively
used in many kinds of magnetic devices such as
transformers, inductors, magnetic heads, in resonance
circuits for high frequency (ranging from 10
3
to 10
11
Hz)
because of their high electrical resistivity, low eddy
current losses, high initial permeability, high saturation
induction, low histeresis loss and reduced physical size.
For these reasons, extensive research work has been
continued over the past few decades to improve their
qualities and efficiencies from the application point of
view to various technical devices.
In this work soft ferrites with cubic spiel
structure with a composition of Ni
1-x
Cd
x
Fe
2
O
4
ferrites for
x = 0.00 to 0.80 in steps of 0.10 have been carried out.
Spinel ferrites are derived from magnetite, Fe
3
O
4
by
partial substitution of the iron ions by other cations. The
general chemical formula spinel materials is AFe
3+
2-
x
B
x
O
4,
where A represents a divalent cation, or a
combination of cations with an average valency of two,
and B is a trivalent cation or a combination of cations
with an average valency of three. The composition
parameter can range between zero and two, but it is
obvious that if x is close to two, these oxides cannot be
considered as ferrites anymore.
Although the spinel ferrite materials are widely
used for so many years in eletro-technical equipment,
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2
Corresponding author: M. Mahbubur Rahman, School
of Engineering & Energy, Murdoch University,
Murdoch, WA 6150, Australia. Email:
much research and development in this field is still in
progress, from the basic as well as from the application
point of view. Although there have been no novel
developments in ferrite materials and components, world
production of ferrites is still increasing and the
development problems connected with these technically
important materials are yet to be solved. As magnetic
materials, ferrites are still the best in high frequency and
very high frequency circuits and they cannot be replaced
by other magnetic elements, since they are relatively
inexpensive and easy to fabricate [1]. A wide variety of
information regarding the development and study of
electromagnetic, dielectric and optical properties are
available in Refs. [2-4].
In cubic spinel ferrite there are two sub-lattices:
tetrahedral (A-site) and octahedral (B-site). Structural,
electro-magnetic and other properties of spinel ferrites
responsible for their applications have been reported to
be strongly dependent upon the cationic distributions on
these sites [5]. Therefore, there are enormous
opportunities to carry out research in order to improve
their magnetic and other qualities by various cationic
replacements in A-site or B-site [6]. In spinel ferrites
cations are found to residing on the tetrahedral A-sites
and octahedral B-sites. Due to the existence of these
cations inter-sublattice (J
AB
) and intra-sublattice (J
AA
,
J
BB
) exchange interactions have been found to occur. It
is generally believed that the magnetic properties of
spinel ferrites depend upon the relative strengths of these
types of exchange interactions. When the cations of A
and B sites are totally magnetic, the inter-exchange
interactions J
AB
are much stronger than J
AA
and J
BB
interactions i.e., J
AB
»J
BB
»J
AA
. On that occasion,
spins have a collinear structure in which moments on the
A-sites are anti-parallel to the moments on the B-sites.
However, when one of the intra-sublattice interactions