Studies on AC Susceptibility of CoFe2O4+ Ba0.9Sr0.1TiO3 Magnetoelectric Composite Material
1D.R.Sapate, 2A.A.Pandit
and 3K.M.Jadhav
1
Department of Physics, Sant Ramdas Arts, Commerce and Science College Ghansawangi (India)
Department of Physics, Yeshwantrao Chavan College Sillod, Aurangabad, (India)
3
Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, (India)
Abstract: AC Susceptibility of ME composites consisting of cobalt ferrite (CoFe2O4) and barium strontium titanate
2
(Ba0.9Sr0.1TiO3) were investigated. The composites were prepared by standard double sintering ceramic method. The X-ray
diffraction analysis was carried out to confirm the phases formed during sintering and also to calculate the lattice parameters. The
AC Susceptibility of magnetoelectric (ME) composites consisting of cobalt ferrite (CoFe2O4) and barium strontium titanate
(Ba0.9Sr0.1TiO3) were investigated. Also using Loria techniques Curie temperature of ferrite and their composites are calculated.
Key words magnetoelectric composites, AC Susceptibility, X-ray diffraction, Loria techniques, Curie temperature etc.
1 Introduction
In the past decades, there has been continued increasing interest in magnetoelectric (ME) materials due to their
attractive physical properties and potential applications in actuators, transducers, field sensors and data storage
devices [1-2].The ME effect can be realized in composite based on product properties. Suitable combination of
piezomagnetic and piezoelectric phase can yield desired ME property. The single domain particles of the ferrite
phase together with large lattice distortion serve as better candidates in piezomagnetic effect and hence enhance the
ME output [3-4]. Numerous single phase ME materials were investigated by many researchers which exhibited
weak ME output. In the present work, we have successfully synthesized (x) CoFe 2O4+ (1−x) Ba0.9Sr0.1TiO3
composites with both ferromagnetic and ferroelectric properties at room temperature. In the present paper the AC
Susceptibility of (x) CoFe2O4+ (1-x) Ba0.9Sr0.1TiO3 composites with x = 0.0 (ferroelectric), x=1.0(ferrite) and x=
0.1(composites) are reported. Curie temperature is determined using AC Susceptibility and Loria techniques.
2 Experimental
The composites containing the two individual phases viz. ferrite (CoFe2O4) and ferroelectric (Ba0.9Sr0.1TiO3) were
prepared by standard double sintering ceramic method. The ferrite phase was prepared through solid-state reaction
using AR grade CoO and Fe2O3 in appropriate molar proportions as starting materials. These basic oxides were
mixed and ground in agate mortar for couple of hours and presintered at 950 0C for12h. The presintered sample is
reground again for 4h and finally post sintered at 1100 0C for 24 h in programmable furnace. The ferroelectric phase
was prepared following the same route by mixing AR grade BaCO3, SrCO3 and TiO2 in their appropriate molar
proportions and presintered at 9500C for 12h. After cooling the sample is ground for 4-5 h and post sintered at
10200C for 16 h. The ME composites were prepared by mixing 10 mole % of CoFe2O4 phase with 90 mole% of
Ba0.9Sr0.1TiO3 phase respectively. The composite mixtures were presintered at 1100 0C for 16 h. The pellets having
3-4 mm thickness and 10 mm diameter were prepared using the hydraulic press.
3 Results and discussion
All the peaks that appear in the XRD pattern have been identified; the occurrence of peaks with specific
indices confirms the formation of cubic spinel structure of CoFe2O4 and pervoskite tetragonal structure of
Ba0.9Sr0.1TiO3. The XRD data was used to calculate the structural parameters. The X-ray diffraction patterns (XRD)
of the (x) CoFe2O4+ (1-x) Ba0.9Sr0.1TiO3 for x=0.1ME composites shows presence of both ferrite and ferroelectric
phases without any additional impurity phase. The intensity of the major peak such as (311) for ferrite phase and
(101) for ferroelectric phase depend on their individual phase fraction in the composite. The susceptibility plots for
all the samples exhibits normal ferrimagnetic behavior which increases with increasing ferrite content x.
Susceptibility increases to a certain temperature and then suddenly falls and reaches zero value. Curie temperature
increases as ferrite content x increases in the composite system under investigation. Curie temperature is calculated
by Loria techniques and ac susceptibility.
4 Conclusions
The analysis of X-ray diffraction pattern shows that the prepared CoFe2O4 sample possesses single phase cubic
spinel structure and the prepared Ba0.9Sr0.1TiO3 sample possesses pervoskite tetragonal spinel structure. The lattice
constant of the composites decreases with increasing ferrite content x. The number of ferrite peaks and intensity
increases with increase in ferrite content x in the composites. Curie temperature (Tc) increases with increase in
ferrite content (x) in composite material.
References
[1] Busch-Vishniac, Inter. J. Phys. Today 51, 28 (1998).
[2] C.M.Kanmadi, ,B.K.Das, Chang Woo Kim et.al. Mater. Chem. and Phys, 116, 6 (2009).
[3] K.K. Patankar, V.L. Mathe, R.N. Patil and B.K. Chougule, Mater. Chem. and Phys, Vol. 96, Issues 2-3, 197 (2006).
[4] R. S .Devan et. al, J. Phys. D: Appl. Phys. 41, 105010 (2008).
1