Influence of CTAB on co-precipitation synthesis of
SrFe12O19
Harikrishnan V, Rajan Babu D, Ezhil Vizhi R*
Crystal Growth and Crystallography Division, School of Advanced Sciences, VIT University, Vellore, India
*
rezhilvizhi@vit.ac.in, Tel.: +91-
Abstract
CTAB assisted synthesis of SrFe12O19 by simple coprecipitation method has been carried out. The structural
studies have been carried out by X-ray diffraction. The
samples have been annealed at 700oC, 800oC and 900oC. The
morphological studies have been carried out by field emission
scanning electron microscope. The magnetic properties have
been studied using vibrating sample magnetometer at room
temperature over a field range of 1.5 T.
added into the above mixture solution to avoid
agglomeration during calcination. Meanwhile in order
maintain pH of the reaction solution (pH 11) NaOH was
added to the solution in appropriate molar ratio. Reddish
brown co-precipitate was washed by deionized water for
5 times and 3 times with ethanol and then dried at
100oC overnight. The resultant was made as powders by
pestle and mortar. The powders were annealed at
different temperatures (700oC, 800oC, 900oC).
Keyword- CTAB, X-Ray diffraction,VSM.
Introduction
Magnetization of 74 emu/g and effective anisotropy
constant (Keff) of 3.577×106erg/cm3 at 300 K and Neel
temperature of 750 K were reported for single crystal
hexagonal strontium ferrite (SrFe12O19) [1]. Hexagonal
M type SrFe12O19 ferrite plays an important role in hard
magnetic materials especially for its large magnetic
anisotropy, high performance-to-cost ratio and good
chemical stability. The hexagonal strontium ferrite has
24 magnetic Fe3+ ions distributed among five
crystallographically distinct magnetic sublattices
namely 2a, 2b, 12k, 4f1 and 4f2. Magnetic moment and
magnetocrystalline anisotropy of Strontium ferrite arises
from the electronic structure of Fe3+ ions at five distinct
magnetic sublattices [2].
During co-precipitation, precipitates are generated
simultaneously and uniformly dispersed through the
solution. To obtain the ferrite powder, the precursor
must be calcined at high temperatures which might lead
to
some
disadvantages
including
chemical
inhomogeneity, coarser particle size and agglomeration.
To prevent the above disadvantages, generally
surfactants are employed. Surfactant addition plays a
major role in the structural and magnetic properties of
hexagonal ferrites [3]. CTAB was selected as the
surfactant.
Experimental
In the present investigations, Sr(NO3)2 and
Fe(NO3)3.9H2O were used as precursors. The Sr2+/Fe3+
ratio was taken to be 12. The precursors were taken in
50 ml deionized water. The CTAB with 1 wt % was
Result
Powder XRD was used to determine the lattice
constants and the crystallite size was determined using
scherrer formula. FE-SEM with EDAX was used to
determine the morphology of the particles and VSM
was used to tap the magnetic properties of the samples.
The results will be discussed in detail.
Conclusion
SrFe12O19 in the presence of CTAB was synthesized
using the co-precipitation method. The prepared
samples were annealed at different temperatures in
order to observe the purity of the samples. Various
characterizations such as FTIR, FE-SEM with EDAX
and VSM have been carried out. The results will be
discussed in detail.
Acknowledgment
The authors are thankful to the management of
VIT University for constant support and
encouragement.
References
[1] B.T.Shrik,
W.R.
Buessem,”Temperature
dependence of Ms and K1of BaFe12O19 and SrFe12O19
single crystals”Journal of Applied Physics, 40 (1969)
1294.
[2] S.P.Marshall, J.B.Sokoloff, “Calculation of the
ferromagnetic resoncelinewidth of Barium ferrite”
Journal of Applied Physics, 67 (1990) 5893.
[3] Jihoon Park et. al, “Maximum energy at elevated
temperatures for hexagonal strontium ferrite (SrFe 12O19)
magnet “.Journal of Magnetism and Magnetic
materials” 355 (2014) 1-6.