Synthesis and Magnetic Properties of Solvothermal
Synthesized Ni-Zn Ferrites
Nivedita L. Raveendran1, P. Saravanan2, R. T. Rajendrakumar3*
1
Advanced Materials and Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore 46, India.
2
Defence Metallurgical Research Laboratory, Hyderabad 500058, India
3
Reader, Department of Nanoscience and Technology, Bharathiar University, Coimbatore 46, India.
*Corresponding author’s e-mail:rtrkumar@buc.edu.in, Tel.: +91-9789757888
Nickel-zinc ferrite nanoparticles were prepared by
solvothermal technique by varying the precursor molar ratio.
The as-prepared and annealed particles were subjected to
various characterization techniques. The XRD analysis
confirmed the formation of cubic spinel structure; while
magnetization measurements demonstrated superparamagnetic
behaviour with maximum Ms value of 33.7 emu/g for
Ni0.5Zn0.5Fe2O4 nanoparticles.
Keywords: Ni-Zn ferrite, solvothermal, superparamagnetic,
EMI suppression.
Introduction
Nickel-zinc ferrite with spinel structure is one
of the most widely studied materials due to its high
versatility in industrial use and its suitability in
biomedical fields, high frequency applications and
electronic devices for EMI suppression. They are
magnetically soft materials and possess high saturation
magnetization, low coercivity, high resistivity and low
dielectric loss. While the processing of Ni-Zn ferrite
nanoparticles was widely investigated by means of
many soft-chemical methods, the applicability of
solvothermal technique is very less explored. The
purpose of the present study is to investigate the effect
of this preparation technique on the properties of mixed
spinel ferrite for improving its functional properties.
Experimental methodology
Nickel-zinc ferrite particles (NixZn1-xFe2O4;
x = 0.0-1.0) were synthesized by varying the precursor
molar ratio of nitrate precursors using solvothermal
method with diethylene glycol as the solvent [1]. The
precursor mixture solution was sealed in a Teflon lined
stainless steel autoclave and kept at 130oC for 20 h. The
particles were prepared without the benefit of any
surfactants. The synthesized particles were annealed at
different temperatures. The as-prepared and annealed
ferrite nanoparticles were characterized by XRD, UVvis spectroscopy and VSM.
Results
The XRD diffraction results confirmed the
spinel structure of the as-prepared nanocrystalline
ferrites with average crystallite size in the range of 40 –
50 nm, as calculated from the Debye-Scherrer’s
formula. From the optical analysis, it was observed that
the band gap decreases as the percentage of Nisubstitution increases. The magnetic hysteresis curves
obtained at room temperature for the as-prepared
samples are shown in Fig. 1. All the curves exhibit
negligible coercivity and remanence magnetization at
300K -indicating the presence of superparamagnetic
behavior [2]. The Ms values 23.6, 28.7 and 33.7 emu/g
were estimated for the nickel-zinc ferrite particles
corresponding to the Ni-precursor molar ratio of 0.7, 0.3
and 0.5, respectively and these values are superior than
that of those obtained for pure zinc (17.5 emu/g)and
nickel ferrites (20.9 emu/g).
40
30
Magnetization (emu/g)
Abstract
20
10
0
NiFe2O4
-10
Ni0.7Zn0.3Fe2O4
-20
Ni0.3Zn0.7Fe2O4
Ni0.5Zn0.5Fe2O4
-30
ZnFe2O4
-40
-20000
-10000
0
10000
20000
Applied Field (Oe)
Fig.1: Room temperature M-H curves
NixZn1-xFe2O4 prepared by solvothermal method.
for
References
[1] Wei Yan etal., Materials Science and Engineering
B 171 (2010) 144–148
[2] R. Ortega-Zempoalteca et. Al., Phys. Status Solidi
A, 1–5 (2014)