R.Selvapriya
1* , R.S.Kavitha
1 , R.Rachel Priyadaharshini 1, M.Alagar
2
1 Department of Physics, The Standard Fireworks Rajaratnam College for Women,Sivakasi 626123,
Tamil Nadu,India
2 PG Department of Physics, Ayya Nadar Janaki Ammal College,Sivakasi.Tamil Nadu, India
* e-mail:selva.priya29e@gmail.com, Tel.: +91-9487714542
Magnetic nanoparticles have been the focus of much glycol was added dropwise to the stirring research recently because they possess attractive properties which could see potential use. Cobalt oxide solution and the mixture was stirred for 2 hours.
The precipitate was filtered and calcined at 60°C. nano particles were synthesised by a simple and versatile co-precipitation method using cobalt acetate as a precursor and sodium hydroxide as precipitating
The dried sample was also annealed at
700° C.
agent. Magnetic measurements by Guoy’s method showed that cobalt oxide nano particles were weakly ferromagnetic. Synthesised cobalt oxide nanoparticles were further characterized by SEM,EDAX,XRD,
Magnetic susceptibility of Co
3
O
4
was studied by
Guoy’s method.
The Guoy balance is a device for measuring the magnetic susceptibility.
Magnetic susceptibility is a dimensionless proportionality constant that indicates the degree
Keywords: Cobalt oxide nanoparticles; Coprecipitation method, Guoy’s method, SEM,
EDAX,XRD, FTIR.
of magnetization of the material in response to an applied magnetic field.
The magnetic susceptibility measured for Co3O4 nanoparticles is χ = 2.8626*10 6
This proves that Co
3
O
4
nanoparticles are weakly
Magnetic nanoparticles have been the focus of much research recently because they possess ferromagnetic while in bulk form they show antiferromagnetic behaviour. attractive properties which could see potential
The FT–IR analysis confirmed the formation of use.
Co
3
O
4
is extensively used in technological applications like information storage devices, metal oxide bonds in Co
3
O
4
nanoparticles. magnetic fluids , catalysts and as an alloying element in permanent magnets.
In our present work, Cobalt oxide nano particles were synthesised by a simple and versatile coprecipitation method using cobalt acetate as precursor and sodium hydroxide as precipitating agent. Magnetic property was studied by measuring the susceptibility of the synthesised nanoparticles by Guoy’s method. Particle size and characterization of phases were performed by XRD .Surface morphology was characterized by Scanning Electron Microscopy and detection of various elemental analysis was carried by
EDAX.
Cobalt acetate (0.5 mol) was dissolved in 50 ml of distilled water. 5 mol of NaOH dissolved in 20 ml of distilled water was added to it. 10 drops of the capping agent ethylene
Fig (1) FTIR spectraof Co
3
O
4
Nanoparticles
Prepared with 5 mol of NaOH annealed at
700°C
A characteristic strong band of the spinel type
Co3O4 structure is observed at about 578.64 cm- confirming the formation of metal bonds.

Particle size and characterization of phases were performed by XRD.
Counts
A
400
300
200
100
0
20 30 70 40 50
Position [°2Theta] (Copper (Cu))
60
Fig (2) XRD result of Co
3
O
4
Nanoparticles
Prepared with 5 mol of NaOH annealed at
700°C
Fig(2) showed three prominent peaks at 16.25°,
36.95° and 65.3°.
The particle size calculated using Debye
Schererr’s formula= 24.1nm
From XRD observations the crystallinity of the samples was also confirmed.
Surface morphology was characterized by
.
Scanning Electron Microscopy.
Fig (3) SEM image of Co
3
O
4
Nanoparticles
Prepared with 5 mol of NaOH
Fig(3) showed rod shaped Co3O4nanoparticles with smooth surface. It clearly indicates the fine rod like particles adsorbed on the surface due to the aggregation. It shows the rod like agglomerates due to the magnetic induction between the particles. Some areas with distorted strings can be seen due to self – alignment orientation that has happened and this can be attributed to the presence of weak interactions.
The EDX spectrum of the product in the fig (4) reveals the presence of only cobalt and oxygen peaks with no other relevant elements present.
Fig (4)EDAX spectra of Co
3
O
4
Nanoparticles
Prepared with 5 mol of NaOH
Table (1) Weight and atomic percentages of
Co
3
O
4
Nanoparticles Prepared with 5 mol of
NaOH
Element App
.Conc
Intensity
Corrn
Weight% Weight%sigma Atomic%
69.66
30.34
O
Co
69.01 1.6530 38.39
60.69 0.9059 61.61
0.72
0.72
Total 100.00
The atomic percentages of Co andO were found to be 30.34% and 69.66% respectively. The atomic ratio of Co and O is 2.9:3.5 which approaches the theoretical value of Co
3
O
4
. The observation further confirms that thefinal product is only highly pure Co
3
O
4 nanoparticles .
This study has been supported by Department of
Physics, The Standard Fireworks Rajaratnam
College for Women,Sivakasi .
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