Materials Science s a nd Applications, 2011, 2, 1675-1681
doi:10.4236/msa.2011.211223 Published Online November 2011 (
Copyright © 2011 SciRes. MSA
Synthesis, Structural and Physical Properties of
Cu1–xZnxFe2O4 Ferrites
Shahida Akhter1*, Deba Prasad Paul1, Md. Abdul Hakim2, Dilip Kumar Saha2, Md. Al-Mamun2,
Alhamra Parveen2
1Department of Physics, University of Chittagong, Chittagong, Bangladesh; 2Materials Science Division, Atomic Energy Centre,
Dhaka, Bangladesh.
Email: *
Received August 30th, 2011; revised October 13th, 2011; accepted October 22nd, 2011.
Zn substituted Cu-Zn ferrites with a composition Cu1–xZnxFe2O4 have been synthesized by standard double sintering
ceramic method and characterized by X-ray diffraction. The single-phase cubic spinel structure of all the samples has
been confirmed from X-ray diffraction analyses. The lattice constant is found to increase linearly with the zinc content
obeying Vegards law. This increase in lattice parameter is explained in terms of the sizes of component ions. It is well
known that density plays a key role in controlling the properties of polycrystalline ferrites. The X-ray and bulk densities
of the Cu-Zn ferrite is significantly decreased whereas porosity increased with increasing Zn concentration, thereby
giving an impression that zinc might be helping in the densification of the materials. SEM micrographs exhibit a de-
crease in grain size with increasing Zn content. The real part of initial permeability, μ increase with increasing Zn
contents upto x = 0.5 after that it decreases with higher Zn content.
Keywords: Ferrites, XRD, Lattice Parameter, Density, Porosity, Permeability
1. Introduction
Ferrites, i.e. ferrimagnetic cubic spinels, possess the com-
bined properties of magnetic materials and insulators.
Ferrites represent an important class of functional mag-
netic materials, largely used in electronic industry and
many other fields of interest, like high frequency devices,
solid state physics, mobile communications of informa-
tion technology [1-3]. By virtue of their magnetic and
semiconducting properties the copper ferrite and its solid
solutions with other ferrites are employed as magnetic
materials foe multilayer chip inductors but also for
transducers of high thermomagnetic sensitivity [4,5]. The
copper ferrite has the structure of the mineral spinel cor-
responding to the general chemical formula MeFe2O4
where Me is Cu or a diavalent ion of the transition ele-
ments and Fe is the iron trivalent ion Fe3+. As long as the
ions are distributed in this way over A (tetrahedral) and
B (octrahedral) position the spinel is known as normal.
When divalent ions are distributed on B position and
trivalents ones on A position the spinel is known as in-
verse. For instance zinc ferrite is normal and copper fer-
rite completely inverse and these are extreme cases. In
reality there is a random distribution of the ions over A
and B sites and each composition is characterized by a
degree of inversion, which very much depend on the
preparation. Mixed ferrites have different degrees of in-
version and CuZn ferrites proved to be very sensitive to
thermal treatments having different cation distribution
upon annealing and mainly upon cooling speed from
high temperatures. The objective of this work is to syn-
thesize the Zn substituted Cu-Zn ferrites and to investi-
gate the effect of zinc ions which substitute iron in ferrite,
on the structural and physical properties of Cu-Zn ferrite
by studying XRD, SEM and frequency dependence per-
2. Materials and Method
Ferrite samples of the chemical formula Cu1–xZnxFe2O4
(x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7) were prepared by
the double sintering ceramic technique. High purity re-
agent powders of CuO, ZnO, and Fe2O3 were dried at
150˚C and were weighed precisely according to their
molecular weight. Intimate mixing for the materials was
carried out for 4 hours using agate mortar and then the
materials in ethyl alcohol are poured into an agate jar
with two types of stainless steel balls of different sizes.
Synthesis, Structural and Physical Properties of CuZn Fe O Ferrites
1676 1–xx2 4
The weight ratio of material to ball was 1:5 under air
atmosphere. The jar was placed into a planetary grinding
miller, and then the materials were continuously milled
for 4 hours. The slurry was dried and was pressed into
disc shape sample. The disc shaped sample was pre-sin-
tered at 850˚C for 6 hours at a heating rate of 4˚C/minute
in air to form ferrite through chemical reaction and then
cooled down to room temperature at the same rate as that
of heating. The pre-sintered material was again crushed
and wet milled for another 4 hours in distilled water to
reduce it to small crystallites of uniform size. The mix-
ture was dried and a few drops of saturated solution of
polyvinyl alcohol were added as a binder.
The resulting powders were pressed uniaxially under a
pressure of (20 Pa) in a stainless steel dies to make pel-
lets. The pressed pellets (9 mm diameter, 3 mm thickness)
toroids (12 mm outer diameter, 8 mm inner diameter and
4 mm thickness) were then finally sintered at 950˚C for 4
hours in air and cooled in the furnace. All samples were
heated slowly in the programmable Muffle furnace (Model
HTL 10/17, Germany) at the rate of about 220˚/hours
increase to avoid cracking of the samples. Then, the tem-
perature was raised to firing temperature of 950˚C and
kept at this temperature for 4 hours. The surfaces of all
the samples were polished in order to remove any oxide
layer formed during the process of sintering. The weight
and dimensions of the pellets were measured to deter-
mine bulk densities. Phase analysis was done by X-ray
diffraction using Phillips (PW3040) X’ Pert PRO X-ray
diffractometer. The powder specimens were exposed to
radiation with a primary beam of 40 kV and 30
mA with a sampling pitch of 0.02˚ and time for each step
data collection was 1.0 sec to characterize it. A 2
was taken from 10˚ to 90˚ to set possible fundamental
peaks where Ni filter was used to reduce CuK
All the data of the samples were analyzed using com-
puter software “X PERT HIGHSCORE”. X-ray diffrac-
tion patterns were carried out to confirm the crystal struc-
ture, where no extra lines were found indicating the ab-
sence of the starting oxides or any other phases. The mi-
crostructures of the samples were done by a scanning
electron microscope (SEM) (model: FEI Inspect). The
SEM micrographs were taken on the smooth surface of
the pellet-shaped polished samples. Before taking micro-
graphs, the surface of the samples were thermally etched
at a temperature of 150˚C below the sintering tempera-
ture. Frequency dependence initial permeability of the
toroid shaped samples was measured with 6500B im-
pedance analyzer at frequency range upto 15 MHz.
3. Results and Discussion
The structural study is essential for optimizing the prop-
erties needed for various applications. The phase identi-
fication and lattice constant determination were performed
on an X-ray diffractometer. The X-ray diffraction pat-
terns of the synthesized Zn substituted mixed ferrite
Cu1–xZnxFe2O4 is shown in Figure 1. All the samples
show good crystallization, with well-defined diffraction
lines. Powder X-ray diffraction of the ferrite samples,
showing well-defined reflections without any ambiguity,
reveals the formation of single-phase cubic spinel struc-
ture and all the peaks observed match well with those of
Mg-Cu-Zn, Mg-Cu and Zn-Mg ferrites reported earlier
[6-8]. The X-ray lines show considerable broadening, in-
dicating the fine particle nature of the ferrite powder. It is
obvious that the characteristic peaks for spinel Cu-Zn
ferrites appear in all samples as the main crystalline
phase. The peaks (220), (311), (222), (400), (422), (511)
and (440) correspond to spinel phase. A strong diffrac-
tion from the planes (311), (511) and (440) as well as
weak diffraction from the planes (220), (222), (400) and
(422) appeared in the X-ray diffractograms. Generally,
for the spinel ferrites the peak intensity depends on the
concentration of magnetic ions in the lattice.
After that, using the X-ray data, the lattice constant (a0)
and hence the X-ray densities were calculated. The lattice
constant was determined through the Nelson-Rilay ex-
trapolation method. The values of the lattice constant ob-
tained from each reflected plane are plotted against Nel-
son-Rilay function [9]
12 cossincosF
 
, where
is the
Bragg’s angle and straight lines are obtained as shown in
Figure 2. The accurate values of lattice constant, a0 were
estimated from the extrapolation of these lines to F(
) =
0 or
= 90˚.
Figure 3 shows the variation of lattice constant with
Zn concentration. A linear increase was evidenced in the
lattice constant with increasing Zn2+ ion concentration
from 8.365 Å for Cu-Zn ferrite for x = 0.0 to 8.439 Å for
x = 0.7. The increase in lattice constant with content of
Zinc indicates that the present system obeys the Vegard’s
law [10]. An increase in lattice constant with an increase
in the content of Zn can be attributed to the ionic size
differences since the unit cell has to expand when sub-
stituted by ions with large ionic size. Since the ionic
20 30 40 50 60 70
Position (2)
Intensity (A.U)
Figure 1. XRD pattern of Cu1–xZnxFe2O4 (x = 0.0 - 0.7).
Copyright © 2011 SciRes. MSA
Synthesis, Structural and Physical Properties of Cu1–xZnxFe2O4 Ferrites
Copyright © 2011 SciRes. MSA
Figure 2. Variati on of lattice parameter with N-R function.
Figure 3. Vari ati on “a” with Zn content.
radius of Zn2+ ions ( = 0.82 Å) [11] is larger than
that of Cu2+ ions ( = 0.73 Å) [12], the substitution is
expected to increase the lattice constant with the increase
in x throughout the concentration studied. A similar lin-
ear variation has also been observed in Zn-Mg [8], Li-Mg
[13]; Zn-Mg-Cu [14]; Zn-Mg [15]; and Li-Cd [16] ferrites.
It was reported [17] that the value of lattice constant of
CuFe2O4 is 8.380 Å. Our experimental value is 8.365 Å,
which is almost similar to the reported value. This slight
difference in the value of the lattice constant is may be
due to the different scattering source, different sintering
and preparation techniques.
The bulk density,
B, was measured by usual mass and
dimensional consideration whereas X-ray density,
was calculated for each sample using the expression [18]
where, M is the molecular weight of the corresponding
composition, N is Avogadro’s number, V = a3 is the
volume of the cubic unit cell and Z is the number of
molecules per unit cell, which is 8 for the spinel cubic
structure. The porosity percentage was then calculated
B and
x values using the expression [19]
1 100
Density plays a key role in controlling the properties
of polycrystalline ferrites [20,21]. The variation of X-ray
and bulk densities is shown in Figure 4. By substituting
Zn in Cu-Zn ferrite, a decrease of X-ray and bulk densi-
ties is observed. The X-ray density depends upon the
Synthesis, Structural and Physical Properties of CuZn Fe O Ferrites
1678 1–x x2 4
Figure 4. X-ray and bulk de nsities with Zn conte nt.
lattice constants and molecular weight of the samples. As
lattice constants increase linearly with the increase of Zn
content, X-ray density decrease owing to the stoichiome-
tery of the sample. Similar decrease pattern is observed
by A. A. Pandit et al. in Mg-Mn ferrite [22]. It is also
observed form Figure 4 that the X-ray densities are lar-
ger in magnitude than corresponding to bulk densities.
This may be due to the existence of pores which were
formed and developed during the sample preparation or
the sintering process [23].
The effect of Zn ion on bulk density and on the poros-
ity is shown in Table 1 and Figure 5. By incorporating
Zn into Cu-Zn ferrite, a significant decrease of the bulk
density can be obtained. The highest density 5.124 g/cm3
whereas lowest porosity 5.61% is obtained for the com-
position of x = 0.0 i.e for pure Cu-ferrite. The porosity
value of all the samples is less than 12% that indicates
the existence of very few pores in the samples. The po-
rosity is found to increase from 5.61% for x = 0.0 to
10.18% for x = 0.7. Moreover this increase in porosity
and decrease in bulk density is due to the increase in
grain size, because the grains may be of irregular shape
and as the sintering proceeds the grain growth takes place
[24]. The intergrainular pores as developed during sin-
tering must also be capable of moving with the grain
boundaries as the growth occurs, requires that the pores
move together and coalesce, and a different transport
mechanism has been indicated. This consists of the trans-
port of gaseous oxygen across the pores and the diffusion
of cations around the pores; it is facilitated by high con-
centration of cation vacancies i.e. excess of Fe2O4. Hence
it is conclude that porosity increase with the addition of
Zn content due to the creation of more cation vacancies
with the reduction of oxygen vacancies [25].
Structural and magnetic properties sensitively depend
on the microstructure of ferrites. Grain size of the micro-
structures is the most important parameter affecting the
magnetic properties of ferrites. Figure 6 shows the SEM
Table 1. Lattice Constant, Bulk density, X-ray density and
porosity of the system Cu1–xZnxFe2O4.
a0 (Å)
Bulk Density,
B (gm/cm3)
0.0 8.36535.124 5.43 5.61 3.822
0.1 8.37245.067 5.42 6.49 3.577
0.2 8.38635.029 5.40 6.79 3.325
0.3 8.39344.974 5.39 7.65 2.902
0.4 8.40834.928 5.36 8.09 2.396
0.5 8.41644.868 5.35 9.02 2.047
0.6 8.42954.787 5.33 10.18 1.565
0.7 8.4396 4.716 5.31 11.26 1.277
Figure 5. Bulk density and Porosity with Zn content .
photographs of Cu-Zn ferrites substitute with Zn content
of 0.0, 0.2, 0.4 and 0.6 respectively. The average grain
size was obtained by line intercept method using SEM.
As shown in Figure 6, the microstructures revealed that
the grain size was influenced by the Zn substitution.
Fro m Table 1, it is observed that with the increase of Zn
substitution, the grain size decreased. In general, the
grain sizes of all samples are smaller than 4 μm, which is
superior to reduce thickness of each layer in multilayer
chip inductors leading to further miniaturization.
The structural and magnetic properties of soft ferrites
are influenced by the composition, additives and micro-
structures of the materials. Among these factors, the mi-
crostructures have great effect on structural and magnetic
properties. It is generally known that the larger grain
sizes, the higher the saturation magnetization and initial
permeability. Figure 7 shows permeability increased
with the increase of Zn content upto x = 0.5 and after that
it decrease. However, the variation of initial permeability
with Zn content was not consistent with the variation of
microstructures, the bulk density and the above empirical
Copyright © 2011 SciRes. MSA
Synthesis, Structural and Physical Properties of Cu1–xZnxFe2O4 Ferrites
Copyright © 2011 SciRes. MSA
x = 0.0 x = 0.2
x = 0.4 x = 0.6
Figure 6. SEM micrographs of Cu1–xZnxFe2O4 ferrites (x = 0.0, 0.2, 0.4, 0.6).
Figure 7. Variation of initial permeability at with Zn con-
tent 10 KHz.
principle. This phenomenon might be explained by the
following equation:
where μi is the initial permeability, Ms is the saturation
magnetization, K is the crystal anisotropy constant, λ is
the magnetostriction constant, and σ is the inner stress.
Nam et al. studies [26] that Zn substitution within small
range in composition plays a crucial role in properties of
NiCuZn ferrites by reducing magnetostriction effects.
Therefore with the increase of Zn content, the increase of
the initial permeability of CuZn ferrites was attributed to
the decrease of magnetostriction constant. The same
conclusions have been confirmed by Nakano’s [27] and
Xiwei qi’s [28] studies. From microstructures we could
see that the grain sizes tended to become smaller and the
distributions of pores were more even which might help
to diminish inner stress and lead to an increase of initial
permeability. In comparison with the reported results of
NiCuZn ferrites prepared by the same method [26], low
temperature sintered CuZn ferrites posses higher initial
permeability and better grain structure. The higher initial
permeability, low cost, low sintering temperature and
smaller grain size characteristics make the Zn substituted
CuZn ferrites be the most potential candidate material for
Multilayer chip inductor (MLCI) industry.
Synthesis, Structural and Physical Properties of CuZn Fe O Ferrites
1680 1–x x2 4
4. Conclusions
A series of Cu1–xZnxFe2O4 ferrites have been synthesized.
The presence of Zn ions causes appreciable changes in
the structure and physical properties of the Zn-substituted
Cu-Zn ferrite. XRD results indicate the single phase of
pure cubic spinel structure. The lattice constant is found
to increase linearly with increasing Zn content in the
mixed Cu-Zn ferrite system obeying Vegard’s law due to
larger ionic radius of Zn2+ compared to Cu2+. X-ray den-
sity decrease with increasing Zn content as lattice con-
stant increase. A remarkable decrease in the value of
bulk density has been found with increasing Zn substitu-
tion Cu-Zn ferrite attaining 98% of theoretical density for
the sample x = 0.0. The porosity is found to increase for
the Zn substitution due to the creation of more cation
vacancies with the reduction of oxygen vacancies. With
the increase of Zn substitution, the grain sizes decreased.
The increases of initial permeability of CuZn ferrites
with Zn content were attributed to the decrease of mag-
netostriction constant.
[1] C. W. Chen, “Magnetism and Metallurgy of Soft Mag-
netic Materials,” North-Holland, Amsterdam, 1990, p. 395.
[2] A. Ono, T. Muruno and N. Kaihara, “Development of
Non-Shrinking Soft Ferrite Composition Useful for Mi-
croinductors Applications,” Japan Electronic Engineer-
ing, Vol. 28, 1991, p. 5.
[3] T. Nomura and A. Nakano, “Japan Society of Powder and
Powder Metallurgy,” Proceeding of the Sixth Interna-
tional Conference on Ferrites, Tokyo, 29 September - 2
October 1992, p. 1198.
[4] S. R. Murthy, “Low Temperature Sintering of MgCuZn
Ferrite and Its Electrical and Magnetic Properties,” Bulle-
tin of Materials Science, Vol. 24, No. 4, 2001, pp. 379-
383. doi:10.1007/BF02708634
[5] E. J. W. Verwey and E. L. Helimann, “Ammonia Gas
Sensing Properties of Nanocrystalline Zn1–xCuxFe2O4
Doped with Noble Metal,” Journal of Chemical Physics,
Vol. 15, No. 1, 1947, p. 4.
[6] A. Bhaskar, B. Rajini Kanth and S. R. Murthy, “Electrical
Properties of Mn Added MgCuZn Ferrites Prepared by
Microwave Sintering Method,” Journal of Magnetism and
Magnetic Materials, Vol. 283, No. 1, 2004, pp. 109-114.
[7] N. Reslescu, E. Reslescu, C. L. Sava, F. Tudorache and P.
D. Popa, “On the Effects of Ga3+ and La3+ Ions in Mg-Cu
ferrite: Humidity-Sensitive Electrical Conduction,” Crys-
tal Research Technology, Vol. 39, No. 6, 2004, pp. 548-
557. doi:10.1002/crat.200310223
[8] B. P. Ladgaonkar, P. N. Vasambekar and A. S. Vain-
gankar, “Cation Distribution and Magnetisation Study of
Nd+3 Substituted Zn-Mg Ferrites,” Turkish Journal of
Physics, Vol. 25, 2001, pp. 129-135.
[9] J. B. Nelson and D. P. Riley, “An Experimental Investi-
gation of Extrapolation Methods in the Derivation of Ac-
curate Unit-Cell Dimensions of Crystals,” Proceeding of
Physical Society, Vol. 57, No. 3, 1945, p. 160.
do i:1 0. 10 88 / 09 59 - 53 09 / 57 /3 / 30 2
[10] L. Vegard, “Zeitschrift Für Physik a Hadrons and Nu-
clei,” Physics and Astronomy, Vol. 5, No. 1, 1921, pp.
17-26. doi :1 0. 10 07 / BF01349 68 0
[11] J. Smit and H. P. J. Wijn, “Ferrites,” Wiley, New York,
1959, p. 143.
[12] D. N. Bhosale, N. D. Choudhari, S. R. Sawant and P. P.
Bakare, “Initial Permeability Studies on High Density
Cu-Mg-Zn Ferrites,” Journal of Magnetism and Magnetic
Materials, Vol. 173, No.1-2, 1997, pp. 51-58.
[13] D. Ravinder and P. Vijaya Bhasker Reddy, “Thermoelec-
tric Power Studies of Polycrystalline Magnesium Substi-
tuted Lithium Ferrites,” Journal of Magnetism and Mag-
netic Materials, Vol. 263, No. 1-2, 2003, pp. 127-133.
[14] S. M. Yunus, H. S. Shim, C. H. Lee, M. A.Asgar, F. U.
Ahmad and A. K. M. Zakaria, “Neutron Diffraction
Studies of the Diluted Spinel Ferrite
ZnxMg0.75–xCu0.25Fe2O4,” Journal of Magnetism and Mag-
netic Materials, Vol. 232, No. 3, 2001, pp. 121-132.
[15] B. P. Ladgaonkar, P. N. Vasambekar and A. S. Vain-
gankar, “Effect of Zn2+ and Nd3+ Substitution on Mag-
netisation and AC Susceptibility of Mg Ferrite,” Journal
of Magnetism and Magnetic Materials, Vol. 210, No. 1-3,
2000, pp. 289-294.
[16] S. S. Bellad, S. C. Watawe and B. K. Chougule, “Micro-
structure and Permeability Studies of Mixed Li-Cd Fer-
rites,” Journal of Magnetism and Magnetic Materials,
Vol. 195, No. 1, 1999, pp. 57-64.
[17] I. P. Parkin, G. E. Eluin, A. V. Komarov, Q. T. Bui and Q.
A. Pankhurst, “Self-Propagating High Temperature Syn-
thesis of Hexagonal Ferrites MFe12O19 (M = Sr, Ba),”
Advanced Materials, Vol. 9, No. 8, 1997, pp. 643-645.
[18] J. Smit and H. P. J Wijn, “Ferrites,” Wiley, New York.
1959, p. 144.
[19] K. Standley, “Oxide Magnetic Materials,” Clarendon, Ox-
ford, 1974, p. 97.
[20] N. Reslescu, L. Sachelarie, L. Reslescu and P. D. Popa,
“Influence of PbO and Ta2O5 on Some Physical Proper-
ties of MgCuZn Ferrites,” Crystal Research Technology,
Vol. 36, No. 2, 2001, pp. 157-167.
[21] Y. Matsuo, M. Inagaki, T. Tomozawa and F. Nakao, “The
Effect of Annealing in the Microstructure and Magnetic
Properties of NiCuZn Ferrites,” IEEE Transactions on
Magnetics, Vol. 37, 2001, p. 2359.
[22] A. A. Pandit, A. R. Shitre, D. R. Shengule and K. M.
Copyright © 2011 SciRes. MSA
Synthesis, Structural and Physical Properties of Cu1–xZnxFe2O4 Ferrites
Copyright © 2011 SciRes. MSA
Jadhav, “Magnetic and Dielectric Properties of
Mg1+xMnxFe2–2xO4 Ferrite System,” Journal of Materials
Science, Vol. 40, No. 2, 2005, pp. 423-428.
do i:1 0. 10 07 / s 10 85 3 -00 5 -60 99 - x
[23] A. Muhammad and A. Maqsood, “Structural, Electrical
and Magnetic Properties of Cu1–xZnxFe2O4 Ferrites (0 x
1),” Journal of Alloys and Compounds, Vol. 460, No.
1-2, 2008, pp. 54-59.
[24] R. S. Tebble and D. J. Craik, “Magnetic Materials,” John
Wiley & Sons, New York, 1969.
[25] T. Abbas, M. U. Islam and M. Ashraf Ch., “Study of Sin-
tering Behaviour and Electrical Properties of Cu-Zn-Fe-O
System,” Modern Physics Letters B, Vol. 9, No. 22, 1995,
pp. 1419-1426. doi:10.1142/S0217984995001418
[26] J. H. Nam, J. H. Oh and W. G. Hur, “The Effect of Mn
Substitution on the Properties of NiCuZn Ferrites,” Jour-
nal of Applied Physics, Vol. 81, No. 8, 1997, pp. 4795-
4797. do i:1 0. 10 63/1. 3 65 46 6
[27] A. Nakano. I. Nakahata and T. Murase, “Electromagnetic
Properties of Low Temperature Sintering MaCuZn Fer-
rites,” Japan Society of Powder and Powder Metallurgy,
Vol. 48, No. 2, 2001, pp. 131-135.
[28] X. W. Qi, J. Zhou, Z. X. Yue, Z. L. Gui and L. T. Li,
“Effect of Mn Substitution on the Magnetic Properties of
MgCuZn Ferrites,” Journal of Magnetism and Magnetic
Materia l s, Vol. 251, No. 3, 2002, pp. 316-322.