Ferrites: Ferrites are mixed metal oxides of magnetic nature in which iron is the main component. In general, ferrites show four different types of crystal structures namely, 1] Ferrospinel Structure. 2] Hexagonal Structure. 3] Garnet Structure. 4] Orthoferrite structure. We are going to discuss about spinel structure as Co Ni ferrite is a spinel ferrite. Ferrospinel Structure. They have the general formula MeFe2O4, where Me is divalent metal ion or a mixture of ions having average valence of two. The unit cell is cubic. The oxygen ions forms a nearly close-packed face centered cubic structure and the metal ions are distributed over tetrahedral and octahedral holes. Normal ferrites:In which all-divalent metal ions occupy A sites and all the Fe3+ occupy B sites. e.x. Zn 2+ [Fe23+] O4 Zn 2+ ions have a very low octahedral preference; therefore they enter the A-sites of the lattice, resulting in normal ferrites. Inverse ferrites:In which all divalent metal ions and half the Fe3+ ions occupy B sites while remaining Fe3+ occupy A sites. e.x. Fe3+[ Fe3+ Ni2+] O4 Mixed ferrites:In which all divalent metal ions and Fe3+ ions are uniformly distributed over the tetrahedral and octahedral sites. Co - Ni ferrite is a mixed spinel ferrite, which has general formulae AII x BII 1-x Fe2O4

2.  For the last several decades, the field of mixed metal oxides has served as a source of
interesting and challenging research problems to technologists chemists and material
scientists. Mixed metal oxides have distinct structural features which play important
role in tailoring their electrical, magnetic, sensor, catalytic and other important
properties which find applications in many important fields.
Mixed metal oxide of nano size show additional properties which finds applications
in varied fields.
Ferrites are a class of mixed metal oxides of magnetic nature in which iron is the
main component.
The ferrites with ferrospinnel structure have the general formula MeFe2O4 where Me
is a divalent metal ion or a mixture of ions having average valence of 2.

3. Preparation of mixed ferrospinnel ferrites :CoXNi(1-x)Fe2O4(where x= 0 ,
0.5, & 1)
Characterization of the ferrites :
>X-ray powder diffraction ( XRD) technique
>Infra Red Spectroscopy(FTIR)
 Study of Solid State Properties:
A) Magnetic properties
1) Saturation magnetisation
2) Retentivity
3) Coercivity
4) Loss
B) Electrical properties
1) Conductivity
2) Dielectric constant
THE PRESENT INVESTIGATION INCLUDES

4. PREPARATIONOF SAMPLES
COMBUSTION METHOD
Quantity of each sample prepared: 5 gms.
Table :Stoichiometric quantities of different salts in each sample

5. SALT SOLUTION
NTA
GLYCENE
PASTY MASSRESIDUE
FINE POWDERSAMPLE

6. Powder X-ray diffraction patterns for the samples
under investigation were taken on Rigaku D-Max
IIC diffractometer.
The particle size has been calculated from X-ray
patterns using Scherrer formula.
Characterisation
• X-ray diffraction (XRD)
• Powder diffraction method

7.  Background counts were taken using KBr pellet.
 IR spectra of KBr and the sample in the ratio of
100:1 were recorded in the wave range 4000-300
cm-1; on Shimadzu IR spectrophotometer.
INFRA RED SPECTROSCOPY (FTIR)

8. SOLID STATE PROPERTIES:
• Magnetic properties
The measurements were done on the usual
hysteresis loop tracer and also on automated high
field magnetic loop tracer.
The hysteresis loop of the samples were recorded.
The magnetic parameters were estimated.

9. • Electrical properties
• Conductivity
Two- probe method.
The resistivity of the samples was measured from room
temperature to 500° c .
The variation of resistivity with temperature was studied for
the samples.

10. • Dielectric constant
The dielectric measurements were done on the samples at
room temperature using HPCA 6440B

11. 20 30 40 50 60 70 80
Intensity(a.u.)
2degree)
CoFe2
O4
Co0.5
Ni0.5
Fe2
o 4
NiFe2
o4
•The dhkl and 2Ɵ values are in agreement with the reported values in
JCPDS data files.
RESULTS AND DISCUSSION
• Particle size 33 nm
• Particle size 26 nm
• Particle size 21 nm
• XRD AND PARTICLE SIZE

12. 1000 2000 3000 4000 5000
0
20
40
60
80
100
%Transmittance
Wavenumber (cm-1)
NiFe2
o4
1000 2000 3000 4000 5000
0
10
20
30
40
50
60
70
%Transmittance
Wavenumber (cm-1)
Co0.5
Ni0.5
Fe2
O4
1000 2000 3000 4000 5000
0
20
40
60
80
100
%Transmittance
Wavenumber (cm-1)
CoFe2
O4
IR SPECTRA
•IR spectra of the samples shows the
absorption bands which are in agreement
with the normal absorption bands of
ferrites.

13. -8 -6 -4 -2 0 2 4 6 8
-58
-38
-19
0
19
38
58emu/gm
x 1000 Oe -8 -6 -4 -2 0 2 4 6 8
-60
-40
-20
0
20
40
60
emu/gm
1000xOe
-8 -6 -4 -2 0 2 4 6 8
-60
-40
-20
0
20
40
60
B
A
HYSTERESIS LOOPS
SAMPLE 1:NiFe2O4 SAMPLE 2: CO0.5Ni0.5Fe2O4
SAMPLE 3: CoFe2O4

14. TABLE: saturation magnetisation, retentivity, coercivity, loss of the samples.
Sample Saturation
Magnetisation
emu/gm
Retentivity
emu/gm
Coercivity
Oe
Loss
erg/cm3
1 51.52 15.985 287.5 163.134
2 50.897 9.885 151.00 190.40
3 51.99 8.9 114.00 14.87

15. ELECTRICAL RESISTIVITY
1.0 1.5 2.0 2.5 3.0 3.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Log
1000/T (K-1)
1.0 1.5 2.0 2.5 3.0 3.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Log
1000/T (K-1)
1.0 1.5 2.0 2.5 3.0 3.5
1
2
3
4
5
6
Log
1000/T (K-1)
SAMPLE 1: NiFe2O4
SAMPLE 2: CO0.5Ni0.5Fe2O4
SAMPLE 3: CoFe2O4
•A semiconductor behavior is observed for all samples.
A high value of resistivity 2.3659×105 ohm .cm is
observed for sample 3 whereas for sample 1 and sample
2 it is 1.336×105 ohm .cm and 1.7322×105 ohm .cm
respectively

16. DIELECTRIC CONSTANT
1 2 3 4 5 6 7
15
30
45
60
75
90
DielectricConstant
Log f
1 2 3 4 5 6 7
0
20
40
60
80
100
120
140
DielectricConstant
Log f
1 2 3 4 5 6 7
0
50
100
150
200
250
300
350
DielectricConstant
Log f
SAMPLE 1: NiFe2O4
SAMPLE 2: CO0.5Ni0.5Fe2O4
SAMPLE 3: CoFe2O4
•It can be seen from the plots that dielectric
constant is found to decrease with increase in
frequency reaching a very low value at higher
frequency for all the samples. This shows that
ferrite acts as dielectric material at low
frequency regions. The value of dielectric
constant at 20 Hz for sample 1 is 84.52, sample
2 is 117.97 and sample 3 is 246.01

17. • The combustion method used for the preparation results in fine
particle ferrite
• The samples prepared are highly magnetic with low values of
Coercivity and loss.
• The hysteresis loss and Coercivity for the sample 3 is found to
be low. This confirms that the magnetic properties are
dependent on particle size.
• The nature of resistivity plot exhibits semi- conductor
behavior .
• Ferrite acts as dielectric material at low frequency regions.
CONCLUSIONS

18. 1. Smit and H. P. J. Wijn, Ferrite, Philips Technical Library, Eindhoven,
The Netherlands, (1959) 137.
2. Solid State Chemistry by C.N.R.Rao
3. R. M. Cornell, U. Schertmann, The Iron Oxides: Structure, Properties,
Reactions, Occurrence and Uses, VCH Publishers, Weinheim, 1996.
4. K. J. Standley, ‘Oxide Magnetic Materials’
(Oxford: Claredon Press, 1972).
5. C. Kittel, Introduction to Solid State Physics, Wiley, New York,
(1976).
6. R.B. Tangsali, S.H. Keluskar, G.K.Naik and J.S.Budkuley, Journal of
Material science (2007)42,878-882.
7. Dependence of dielectric behavior of Mn-Zn ferrite on sintering
temperature.
M.A.Ahmed,E.H.EL-Khawas,F.A.Radwan Journal of Material
science 36(2001)5031-5035
8. www.googlebooks.com
REFERENCES

19. ACKNOWLEGMENT
1.Dept. of chemistry-Goa university
2.N.I.O-Dona paul
3.Dept. of PHYSICS & CHEMISTRY P.E.S
COLLEGE

20. THANK YOU