Materials Sciences and Applicatio n, 2011, 2, 1097-1108
doi:10.4236/msa.2011.28148 Published Online August 2011 (http://www.SciRP.org/journal/msa)
1097
Effect of Oxalate Precursor Formation
Temperature on Magnetic Properties of NiCuZn
Ferrites
Neelam S. Shinde1*, Sujata S. Khot1, Bhimrao P. Ladgaonkar2, Bharat B. Kale3, Sanjay Apte3, Prasad
M. Tamhankar4, Shrikant C. Watawe4
1Dr.Datar Science, Dr.Behere Arts and Shri. Pilukaka Joshi Commerce (D.B.J.) College, Chiplun, Maharashtra, India; 2Shankarrao
Mohite Maha vi dhayalaya, Akl u j, Solapur, Maharashtra, India; 3Center for Materials for Electronic Technology, Pashan, Pune, India;
4Lokmanya Tilak Institute of Postgraduate Teaching and Research, Gogate Jogalekar College, Ratnagiri, Maharashtra, India.
Received January 1st, 2011; revised March 10th, 2011; accepted June 13th, 2011.
ABSTRACT
Ni-Cu-Zn ferrites with general formula Ni0.5Zn0.5-x/2Cux/2Fe2O4 (with x = 0.3, 0.4, 0.5 and 0.6) have been synthesized
using oxalate precursor method with different precursor reaction temperatures in the range 10˚C to 70˚C. The Curie
temperatures obtained using AC susceptibility measurements are found to be in the range 150˚C to 350˚C, the meas-
urements also show single domain structure for all the samples except few compositions obtained at 35˚C precursor
reaction temperature, show a multi-domain behaviour. The saturation magnetization is found to be in the range 20 to
51 emu/gm, while the magnetic moment is found to be in the range 0.63 to 1.5 µB. Th e hysteresis losses were found to
be maximum for the samples obtained at precursor reaction temperature of 35˚C. The grain size is found to be in the
range 0.4 to 2.0 µm.
Keywords: Magnetic Materials, Temperature of Chemical Reaction, Magnetic Susceptibility, Curie Temperature
1. Introduction
NiZn ferrites have been used in the high frequency ap-
plications and also multilayer chip conductor with silver
as a suitable material for inner conductor, however co-
firing silver with the NiZn ferrites at higher temperature
of 1250˚C is unsuitable as the melting point of silver is
961˚C [1,2]. Cu2+ can be introduced to reduce the sinter-
ing temperature and at the same time enhance sintering
process [3, 4]. Ni-Cu-Zn Ferrites having oxygen defi-
ciency have been reported to be useful materials in CO2
decomposition in reducing green house effect with 100%
efficiency [5]. The synthesis of ferrites can be carried out
using different methods but the low temperature synthe-
sis and molecular level mixing is reported to be useful in
obtaining desired magnetic properties and the reaction
kinematics in a chemical process dependent on the tem-
perature at which it is carried out [6]. A combination of
lower reaction temperature followed by calcination at
suitable elevated temperature for the solid state reaction
could be useful for synthesizing the ferrites with required
parameters.
Various preparation techniques such as sol gel auto
combustion [7], microwave assisted combustion synthe-
sis [8,9], soft chemical method [10-14], combustion syn-
thesis [15] have been used to synthesize ferrites. In the
present communication, efforts have been made to syn-
thesize Ni-Cu-Zn ferrites in two steps, involving oxalate
co-precipitation at three different reaction temperatures
[16], followed by calcination at 600˚C for the completion
of the solid state reaction. The choice of calcinations
temperature has been based on the fact that ferrous ox-
alate gets converted into ferrous oxide at 400˚C [17]
while the ferrite formation is reported to take place at
around 600˚C [18,20]. It has also been reported th at there
is exothermic peak around 620˚C due to crystallization
[21,22].
2. Experimental
Ni-Cu-Zn ferrites with general formula Ni0.5Zn0.5-x/2Cux/2-
Fe2O4 (with x = 0.3, 0.4, 0.5 and 0.6) have been synthe-
sized using AR grade metal sulphates as starting material.
The stoichiometric proportions of metal sulphates were

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1098
added to 200 ml distilled water. The temperature of
chemical reaction was maintained at three different val-
ues i.e. 10˚C, 35˚C and 70˚C, using thermally controlled
water bath. The chemicals were also maintained at the
three temperatures before the chemical reaction was car-
ried out. The reaction temperatures were chosen consid-
ering the room temperature of the work place during
summer. The summer room temperature is in the range
of 35˚C which could be easily maintained. Th e other two
temperatures were chosen which have the variation of
more than 25˚C on either side of the room temperature.
Ammonium oxalate was added drop by drop in the
flask containing the metal sulphates up to the completion
of the chemical reaction. Barium chloride test was used
to confirm the completion of chemical reaction. The fil-
trate was filtered and washed with distilled water and
dried using electric la mp. Oxalates in precursor act like a
combustion agent which helps in lowering the calcination
temperature. Therefore the solid state reaction to obtain
the ferrites was carried out in muffle furnace at optimized
temperature of 600˚C for 6 Hrs for all samples irrespec-
tive of the oxalate reaction temperature. X-ray diffracto-
grams were recorded using Philips PW 1710 powder
diffractometer by scanning in the range 20˚C to 80˚C.
AC susceptibility measurements were carried out using
Helmholtz double coil setup operated at 263 Hz with a
constant field of 7 Oe. Hysteresis measurements were
done using the hysteresis loop tracer. SEM micrographs
were taken on JEOL-JEM-6360 microscopes to obtain
the grain size of the samples.
3. Results and Discussions
The XRD patterns indicate the single phase cubic struc-
ture for all the samples. The effects of reaction tempera-
tures on the position of most intense (311) peak in the
diffraction pattern are shown in Figures 1 2, 3 and 4. The
peak is found to shift towards smaller angle for reaction
temperature 35˚C for all the compositions, while the peak
intensities are found to be maximum for reaction tem-
perature of 70˚C for x = 0.3 and 0.4 while for x = 0.5 and
0.6 the maximum intensity is observed at reaction tem-
perature of 10˚C. The reaction temperatures show their
effects in position as well as the intensity of the (311)
peak. The variation in peak intensities and sharpness with
reaction temperature has been reported by Qu et.al [23].
They have also reported the increase in grain size, lattice
constant and Ms with reaction temperature.
Figures 5, 6 and 7 depict the variation of normalized
AC susceptibility with temperature for all the composi-
tions at different reaction temperatures. All the samples
at reaction temperature of 10˚C and 70˚C show SD be-
haviour while two compositions at 35˚C show MD be
haviour. The magnetic properties are structure sensitive
and the grain size plays a significant role. The Curie
temperature, at which the normalized susceptibility d rops
off sharply, shows a variation with reaction temperature.
For synthesis at temperature of 10˚C the Curie tempera-
ture is found to be in the range 120 to 220˚C. For the
reaction temperature of 35˚C, it is in the range of 220 to
290˚C while for the reaction temperature of 70˚C it is in
the range 180 to 260˚C. The value of Curie temperature is
found to be minimum for x = 0.4 for all the reaction tem-
peratures while its va lue is maximum fo r the samples syn-
thesized at 35˚C for all the compositions. The Curie tem-
perature depends mainly on A-B interaction which is de-
termined by the cations present in the sample. The substi-
tution of Cu2+ ions in place of Zn2+, changes the magnetic
moment on both the sites whereby the A-B interaction
changes. The Curie temperature is se nsitive to th e calcina-
tion temperature but in the present case even though the
calcination temperature is same for all the samples, there is
variation in Curie temperature with composition as well as
the chemical reaction temperature indicating the effect of
chemical reaction temprature even after calcination.
Figure 8 depicts the hysteresis loops for all the sam-
ples studied. The values of saturation magnetization and
magnetic moment shown in Table 1 are found to in-
crease with increase in reaction temperature up to x = 0.4
while for x > 0.4 the maximum value is observed for re-
action temperature of 35˚C. The retentivity for all the
samples is found to increase with reaction temperatures.
Shrotri et al. [10 ] have reported decrease in Ms with
increase in Cu2+ content for ferrites with similar compo-
sition synthesized at 80˚C. The substitution of Cu2+ ions
is reported to show canting behaviour for higher concen-
tration [24,11,19] which is also observed in the present
case. The variation in magnetization is also found to de-
pend upon the reaction temperature, where it is found to
show larger values for reaction temperature of 35˚C
which happens to be the room temperature.
The SEM micrographs for the samples with x = 0.4
and x = 0.5 at the three reaction temperatures studied are
shown in Figures 9 and 10. Maximum grain size is ob-
tained for x = 0.4 which is in the range 0.6 to 1.95 µm for
the samples studied. The grain size is found to increase
with reaction temperature indicating the effect of reaction
history on the grain size. The grain size is found to be
maximum for the reaction temperature of 35˚C which
happens to be the room temperature.
4. Conclusions
The oxalates co-precipitation reactions were carried out
at 10˚C, 35˚C and 70˚C temperatures while the solid state
reaction was carried out at 600˚C for all the samples,
show variation with composition as well as reaction
temperature in the structural as well as magnetic proper-

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1099
Figure 1. Variation of most intense (311) peak with temperature of chemical reaction for the composition x = 0.3.

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1100
Figure 2. Variation of most intense (311) peak with temperature of chemical reaction for the composition x = 0.4.

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites1101
Figure 3. Variation of most intense (311) peak with temperature of chemical reaction for the composition x = 0.5.

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1102
Figure 4. Variation of most intense (311) peak with temperature of chemical reaction for the composition x = 0.6.

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1103
Figure 5. Variation of normalized AC susceptibility for compositions x = 0.3, x = 0.4, x = 0.5 and x = 0.6 at reaction tempera-
ture 10˚C.
Figure 6. Variation of normalized AC susceptibility for compositions x = 0.3, x = 0.4, x = 0.5 and x = 0.6 at reaction tempera-
ture 35˚C.
Figure 7. Variation of normalized AC susceptibility for compositions x = 0.3, x = 0.4, x = 0.5 and x = 0.6 at reaction tempera-
ture 70˚C.

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1104
(a) (b) (c)
(d) (e) (f)
(g) (h) (i)
(j) (k) (l)
Temperature X = 0.3 X = 0.4 X = 0.5 X = 0.6
10˚C a d g j
35˚C b e h k
70˚C c f I l
Figure 8. The hysteresis loops for compositions x = 0.3, x = 0.4, x = 0.5 and x = 0.6 at reaction temperatures 10˚C, 35˚C and
70˚C.
(a)

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites1105
(b)
(c)
Figure 9. SEM micrographs for x = 0.4 at reaction temperatures (a) 10˚C, (b) 35˚C and (c) 70˚C.
(a)

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1106
(b)
(c)
Figure 10. SEM micrographs for x = 0.5 at reaction temperatures (a) 10˚C, (b) 35˚C and (c) 70˚C.
Table 1. Variation of magnetic properties with composition and chemical reaction temperature.
Temperature
of reaction (˚C) Composition parameter x Ms (emu/gm)Magnetic moment (B) Retentivity
(emu/gm) Curie Temperature (˚C) Grain size
(m)
0.3 32.06 1.00 20.04 180 -
0.4 20.25 0.63 14.17 120 0.6
0.5 28.57 0.89 22.85 220 0.4
10
0.6 28.51 0.67 17.59 175 -
0.3 42.97 1.33 35.29 260 -
0.4 50.44 1.57 38.95 220 1.0
0.5 46.18 1.43 32.98 260 0.6
35
0.6 38.17 1.21 27.43 290 -
0.3 47.02 1.46 37.12 220 -
0.4 51.05 1.58 39.03 180 1.95
0.5 46.07 1.43 35.83 250 1.5
70
0.6 37.09 1.15 28.53 260 -

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1107
ties, indicating the effect of chemical reaction history on
the properties of ferrites. The temperature of chemical
reaction may conveniently be used to synthesize ferrites
with suitable properties.
REFERENCES
[1] Wei-Chih Hsu, S. C. Chen, P. C. Kuo, C. T. Lie and W. S.
Tsai, “Preparation of NiCuZn Ferrite Nanoparticles from
Chemical Co-Precipitation Method and the Magnetic
Properties after Sintering,” Material Science and Engi-
neering: B, Vol. 111, August 2004, pp. 142-149.
[2] J. Dong-yin and B. Pei, “Transactions of Nonferrous
Metals,” Society of China, Vol. 16, 2006, pp. 67-70.
[3] H. Su, H. W. Zhang, X. L. Tang and X. Y. Xiang, “High
Permeability and High Curie Temperature NiCuZn Fer-
rite,” Journal of Magnetism and Magnetic Materials, Vol.
283, No. 3-4, December 2004, pp.157-163.
doi:10.1016/j.jmmm.2004.05.017
[4] M. M. Haque, M. Huq and M. A. Hakim, “Influence of
CuO and Sintering Temperature on the Microstructure
And Magnetic Properties of Mg-Cu-Zn ferrites,” Journal
of Magnetism and Magnetic Materials, Vol. 320, No. 21,
November 2008, pp. 2792-2799.
doi:10.1016/j.jmmm.2008.06.017
[5] L. J. Ma, L. S. Chen and S. Y. Chen, “Study on the Char-
acteristics and Activity of Ni-Cu-Zn Ferrite for Decom-
position of CO2,” Materials, Chemistry and Physics, Vol.
114, No, 2-3, April 2009, pp. 692-696.
doi:10.1016/j.matchemphys.2008.10.050
[6] Mathew George, Asha Ma ry John, Swapna S. Nair, P. A.
Joy and M. R. Anantharaman, “Finite Size Effects on the
Structural and Magnetic Properties of Sol-Gel Synthe-
sized NiFe2O4 Powders,” Journal of Magnetism and
Magnetic Materials, Vol. 302, No. 1, July 2006, pp.
190-195. doi:10.1016/j.jmmm.2005.08.029
[7] Zhenxing Yue, Ji Zhou, Longtu Li, Hongguo Zhang and
Zhilun Gui, “Synthesis of Nanocrystalline NiCuZn ferrite
Powders by Sol-Gel Auto-Combustion Method,” Journal
of Magnetism and Magnetic Materials, Vol. 208, No. 1-2,
January 2000, pp. 55-60.
doi:10.1016/S0304-8853(99)00566-1
[8] M. Yan and J. Hu, “Microwave Sintering of High Per-
meability (Ni0.20Zn0.60Cu0.20)Fe1.98O4 Ferrite at Low Sin-
tering Temperatures,” Journal of Magnetism and Mag-
netic Materials, Vol. 305, No. 1, October 2006, pp. 171-
176. doi:10.1016/j.jmmm.2005.12.008
[9] S. C. Watawe, S. Keluskar, Gonbare and R. B. Tangsali,
“Preparation and Magnetic Properties of Cadmium Sub-
stituted Lithium Ferrite Using Microwave Induced Com-
bustion,” Thin Solid Films, Vol. 505, No. 1-2, May 2006,
pp. 168-172. doi:10.1016/j.tsf.2005.10.032s
[10] J. J. Shrotri, S. D. Kulkarni, C. E. Deshpande, A. Mitra, S.
R. Sainkar, P. S. A. Kumar and S. K. Date, “Effect of Cu
Substitution on the Magnetic and Electrical Properties of
Ni-Zn Ferrite Synthesized by Soft Chemical,” Materials
Chemistry and Physics, Vol. 59, No. 1, April 1999, pp.
1-5. doi:10.1016/S0254-0584(99)00019-X
[11] C. W. Kim and J. G. Koh, “A Study of Synthesis of Ni-
CuZn Ferrite Sintering in Low Temperature by Metal Ni-
trates and Its Electromagnetic Property,” Journal of
Magnetism and Magnetic Materials, Vol. 257, No, 2-3,
February 2003, pp. 355-368.
doi:10.1016/S0304-8853(02)01234-9
[12] I. Z. Rahman and T. T. Ahmed, “A Study on Cu substi-
tuted Chemically Processed Ni-Zn-Cu Ferrites,” Journal
of Magnetism and Magnetic Materials, Vol. 290-291, No.
2, April 2005, pp. 1576-1579.
[13] P. S. A. Kumar, J. J. Shrotri, S. D. Kulkami, C. E. Desh-
pande and S. K. Date, “Low Temperature Synthesis of
Ni0.8Zn0.2Fe2O4 Powder and Its Characterization,” Mate-
rials Letters, Vol. 27, No. 6, August 1996, pp. 293-296.
doi:10.1016/0167-577X(96)00010-9
[14] S. A. Ghodake, U. R. Ghodake, S. R. Sawant, S. S. Su-
ryavanshi and P. P. Bakare, “Magnetic Properties of Ni-
CuZn Ferrites Synthesized by Oxalate Precursor Me-
thod,” Journal of Magnetism and Magnetic Materials,
Vol. 305, No. 1, October 2006, pp. 110-119.
[15] Y. Li, J. P. Zhao, J. C. Han and X. D. He, “Combustion
Synthesis and Characterization of NiCuZn Ferrite Pow-
ders,” Materials Research Bulletin, Vol. 40, No. 6, June
2005, pp. 981-989.
doi:10.1016/j.materresbull.2005.02.018
[16] J. L. M. de Vidales, A. Lo´pez-Delgado, E. Vila and F. A.
Lo´pez, “The Effect of the Starting Solution on the Phys-
ico-Chemical Properties of Zinc Ferrite Synthesized at
Low Temperature,” Journal of Alloys and Compounds,
Vol. 287, No. 1-2, June 1999, pp. 276-283.
doi:10.1016/S0925-8388(99)00069-9
[17] X. Y. Li, G. X. Lu and S. B. Li, “Synthesis and Charac-
terization of Fine Particle ZnFe2O4 Powders by a Low
Temperature Method,” Journal of Alloys and Compounds,
Vol. 235, No. 5, March 1996, pp. 150-155.
doi:10.1016/0925-8388(95)02022-5
[18] T. Nakamura, “Low-Temperature Sintering of Ni-Zn-Cu
Ferrite and Its Permeability Spectra,” Journal of Magnet-
ism and Magnetic Materials, Vol. 168, No. 3, April 1997,
pp. 285-291. doi:10.1016/S0304-8853(96)00709-3
[19] S. Modak, M. Ammar, F. Mazaleyrat, S. Das and P. K.
Chakrabarti, “XRD, HRTEM and Magnetic Properties of
Mixed Spinel Nanocrystalline Ni-Zn-Cu Ferrite,” Journal
of Alloys and Compounds, Vol. 473, No. 1-2, April 2009,
pp.15-19. doi:10.1016/j.jallcom.2008.06.020
[20] U. R. Lima, M. C. Nasar, R. S. Nasara, M. C. Rezende, J.
H. Araújo and J. F. Oliveira, “Synthesis of NiCuZn Fer-
rite Nanoparticles and Microwave Absorption Charac-
terization,” Materials Science and Engineering B, Vol.
151, No. 3, July 2008, pp. 238-242.
doi:10.1016/j.mseb.2008.06.032
[21] Y. P. Fu, C. H. Lin and C. W. Liu, “Preparation and
Magnetic Properties of Ni0.25Cu0.25Zn0.5 Ferrite from Mi-
crowave-Induced Combustion,” Journal of Magnetism
and Magnetic Materials, Vol. 283, No. 1, November
2004, pp. 59-64.

Effect of Oxalate Precursor Formation Temperature on Magnetic Properties of Nicuzn Ferrites 1108
[22] J. Y. Hsu, W. S. KO, H. D. Shen and C. J. Chen, “Quasi
Static Electromagnetic Field Problems,” IEEE Transac-
tions on Magnetics, Vol. 30, 1994, p. 6.
[23] Y. Q. Qu, H. B. Yang, N. Yang, Y. Z. Fan and H. Y. Zhu,
“The Effect of Re action Te mperature on the Pa rticle Size,
Structure and Magnetic Properties of Co-Precipitated
CoFe2O4 Nanoparticles,” Materials Letters, Vol. 60, No.
29-30, December 2006, pp. 3548-3552.
doi:10.1016/j.matlet.2006.03.055
[24] J. Slama, A. Gruskova, M. Usakova, E. Usak and R. Do-
soudil, “Contribution to Analysis of Cu-Substituted NiZn
Ferrites,” Journal of Magnetism and Magnetic Materials,
Vol. 321, No. 19, October 2009, pp. 3346-3351.
doi:10.1016/j.jmmm.2009.06.024