THAPAR UNIVERSITY PATIALA M TECH 2 nd sem. 2012 MATERIALS AND METALLURGICAL ANOOP PRATAP SINGH ROLL NO 601102002 Under the supervision Dr. PUNEET SHARMA 12-Jan-13 1
THAPAR UNIVERSITY PATIALA
M TECH 2nd sem. 2012
MATERIALS AND METALLURGICAL
ANOOP PRATAP SINGH
ROLL NO 601102002
Under the supervision
Dr. PUNEET SHARMA
12-Jan-13 1
2
“HEXA-FERRITE THIN FILM
PREPARED BY SOL-GEL
METHOD”
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Hexa-ferrites
The Hexa-Ferrites are also assigned as Hard because the Magnetization directions not change easily.
Formula M (Fe12O19)
Where M =Ba, Sr, Pb
It has one c- axis which easily magnetized
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M -type (BaFe12O19 )
U-type (Ba4Me2Fe36O60)
W- type (BaMe2Fe16O27)
X- type (Ba2Me2Fe28O46)
Y- type (Ba2Me2Fe12O22)
Z- type (Ba3Me2Fe24O41)
Type of Hexa-ferrites
Main type
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Physical properties of Ba, Sr, and Pb Hexa-ferrite
Lattice constant (a)
Lattice constant (c)
Mass density(gm/cm3)
µ0.MS(RT)
(T)
Tc(K)
BaM 0.589 2.32 5.3 0.48 740
SrM 0.587 2.31 5.11 .043 745
PbM 0.588 2.30 5.68 0.43 725
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Processing of Hexa-Ferrites
Chemical Co-precipitation
Method
Self Propagating High
Temperature Synthesis,
Salt Melting Method,
Ball Milling,
Solid State Method, and
Sol-Gel Method
Sol-Gel-The Sol-Gel process involves the
transition of a solution system
from a liquid "Sol" (mostly
colloidal) into a solid "Gel" phase.
The Sol-Gel Synthesis is to “dissolve” the compound in a liquid in order to bring it back as a solid in a controlled manner
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Why
Sol
-Gel
??
Advantages of Sol- Gel method To provide corrosion protection Produced high purity productsCan have low temperature
sintering capability, usually 200-600°C.
Economically it is cheapLow processing Temperature Good shape abilityGood homogeneity Processing
Disadvantage of Sol -Gel Method High cost of raw materialLarge shrinkage damage
processingResidual fine pores and
hydroxylsHealth , hazards of organic
solutionsEasily cracking during the
drying stageTake Large processing times
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Sol –Gel Formation
Sol Formation Gel Formation
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Deposition Method of thin films
Physical method
Thermal EvaporatorSputtering Pulse Laser
DepositionsArc DepositionsElectro-Spray
Deposition
Chemical methods
Electro-PlatingChemical Solution
Deposition Chemical-Vapor DepositionAtomic Layer DepositionsSpin Coating/Spin Casting
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Spin CoatingSol-Gel precursor deposited onto a smooth flat sub-strate that
is spun at a high velocity to centrifugally spread the solution
over the substrate
The speed of spin and the viscosity of sol to determine the
thickness of the deposited film
If process of spread repeated then thickness of film against
increase
Thermal treatment given to crystalline the amorphous spin
coated film such crystalline film can exhibit certain preferred
orientation as a single crystal structure.
To create thin films with thicknesses below 10 nm
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Spin Coating
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