Presentation 14-08-2011 VI

8/4/2019 Presentation 14-08-2011 VI

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Structure and Properties of Doped Nano-Barium

Titanate

BY

PUSPENDU BARIK

Under the guidance ofDr. TAPAS KUMAR KUNDU

Department of Physics

Visva-Bharati, Santiniketan, West Bengal,

INDIA

14

th

August, 2011


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A prefix that means very, very, small.

The word nano is from the Greek word

Nanos meaning Dwarf. It is a prefix used

to describe "one billionth" of something, or

0.000000001.

Nano

The radius of one atom of gold is 0.14 nm.

One human hair is around 100 thousand times bigger.

Virus 10 nm t0 60 nmProtein 1 nm to 20 nmBacteria 30 nm to 10 mPaint pigments 80 nm to 100 nmCarbon for toner 10 nm to 100nm

Example:


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Size ofThings (orange = man-made things)Millimeters Microns Nanometers

Ball of a ball point pen 0.5

Thickness of paper 0.1 100Human hair 0.02 - 0.2 20200

Talcum Powder 40

Fiberglass fibers 10

Carbon fiber 5

Human red blood cell 46E-coli bacterium 1

Size of a modern transistor 0.25 250

Size of Smallpox virus 0.20.3 200300

Electron wavelength: ~10 nm or lessDiameter of Carbon Nanotube 3

Diameter of DNA spiral 2

Diameter of C60 Buckyball 0.7

Diameter of Benzene ring 0.28

Size of one Atom ~0.1


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By virtue of their size.

Exotic electronic and optical properties

High chemical reactivity Extremely high surface/volume ratios

Nanoscience and Nanotechnology

The nanoscale is not just another step towards miniaturization. It is a

qualitatively new scale where materials properties depend on size and shape, as

well as composition, and differ significantly from the same properties in the bulk.

Nanoscience seeks to understand these new properties.

Nanotechnology seeks to develop materials and structures that exhibit novel

and significantly improved properties due to their nanoscale size.

The goals of nanoscience and nanotechnology are:

to understand and predict the properties of materials at the nanoscale

to manufacture nanoscale components from the bottom up

to integrate nanoscale components into macroscopic scale objects and

devices for real-world uses


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2003 Brooks/Cole, adivision ofThomson Learning, Inc. ThomsonLearning

isatrademark used hereinunder license.

Classification of technologically useful electronic materials


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BaO + TiO2

BaTiO3


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Background: Barium Titanate

Perovskite structure: ABO3

The absence of center symmetry in crystal

structure gives rise to spontaneouspolarization

Cubic above Curie temperature;

tetragonal as it cools down.

BariumTitanate (BaTiO3)

the first material to be developed as a

piezoceramic

available in single crystal form

Discovered independently

United States (Waigner and Salomon 1942)

Soviet Union (Wul and Goldman, 1945)

Japan (Miyake and Ueda, 1946).

Applications: detection of mechanical

vibration, actuators, and for generation of

acoustic and ultrasonic vibrations,

Piezoelectricity, Ferroelectricity.

.

Crystal structure of Barium Titanate

Uchino, 1997


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BaTiO3

The First ferroelectric ActivityVon Hippel and coworkers in 1945-46

The First single crystalsProduced in Switzerland in 1947

Different polymorphs of BaTiO3 and accompanying changes in lattice constants and dielectric constants


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High Dielectric Constant Used in DRAMs and thin film capacitors

Voltage Dependence of Dielectric Constants Used in common circuits such as Varactors, filters, resonators

and phase shifter

Ferroelectricity

Non volatile ferroelectric RAM Optical Properties

Nonlinear optics

Semiconducting Properties Substitute any semiconductor (e.g. Si, Ge, GaAs)

Piezoelectricity Micro-motors, Actuators

Pyroelectricity Infrared imaging devices

BaTiO3 nanoparticles overview


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Humidity sensor

The direct and converse piezoelectric effect. In the directpiezoelectric effect, applied stress causes a voltage to appear.

In the converse effect, an applied voltage leads to

development of strain.

The effect oftemperature and grain

size on the dielectric

constant of BaTiO3


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Room-temperature PL spectra of BT thin films

annealed at different temperatures; (a) 200 oC,

(b) 300 oC, (c) 350 oC, (d) 400 oC, (e) 450 oC, (f)

600 oC, and (g) 700 oC, 50 100 150 200Temperature in

oC

RelativeDielectricConstant(r)

Dielectric Properties

Dielectric maximum of

15,000 was observed

at 60 nmJpn. J. Appl. Phys. 42, 6188

(2003)

1 kHz dielectric constant and dielectric loss vs.

grain sizes of nano- BT sintered at 1100 C.


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Objective

Stabilization of tetragonal phases at smaller sizes ofBT. How 3d transition elements in BT stabilize

unusual structural configuration?

Wheather ferroelectricity can be retained even in

nanoparticles by incorporating Fe, Co, Ni and Ceions

Wheather optical properties can be enhanced with

the creation of different defect states

Is addition of dopant modify the dielectric constantat the nano phase of barium titanate?


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Experimental TechniquesA sol gel route was used for the synthesis of BT nanoparticles.

Precursors: Barium acetate, Tetraisopropyl orthotitanate, Metal

nitrate and PVA

Ethyl alcohol:

acetic acid =

1:1

Tetra-isopropylorthotitanate

Stirred for 2 hrs

Solution A

Barium acetateand distilled

water

Metalnitrate

Stirred for 2hrs.

Solution C

Solution B

Transparent

PVA

Clear

gel

Dried and

calcinated

Crystalline

phase of BT


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Solgel Hydroxid Method

Stirring and heating at5070 oC

Stirring for 2h

Stirring for 2h

Ethanol and glacial acetic acid

(1:1 volume ratio)

Cooling to RTTetra-isopropyl orthotitanate

(C122H28O4Ti)

A transparent

solution prepared

Barium hydroxide

Ba(OH)2, 8H2O

Allowed to gel at

room temperature

90100 oC for 1215 h in air to

evaporate the solvents

Heating

dried gel or powder in portions at

400750 oC for 2 h in air


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Light emission from

ferroelectric barium titanate


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Solgel Hydroxid Method

Stirring and heating at5070 oC

Stirring for 2h

Stirring for 2h


(1:1 volume ratio)


(C122H28O4Ti)

A transparent

solution prepared

Barium hydroxide

Ba(OH)2, 8H2O

Allowed to gel at

room temperature



Heating




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XRD pattern for a BaTiO3 nanopowder after heating a

sol-gel precursor at 400C for 2 h in air. The peaks

(211)* and (101) refer to o-BT and t-BT phases.

XRD patterns for BaTiO3 nanopowders after heating a

sol-gel precursor at (a) 600C and (b) 750C for 2 h in

air. A close-up in the inset compares the shift in (101)

peak in the two powders.

Structural properties of barium titanate nanocrystals

, (ii)

or


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HRSEM images showing t-BT nanocrystals of

thin laminates (heated at 750C for 2 h in air).

EPR spectra for BaTiO3 nanopowders after

heating a sol-gel precursor at (a) 400C, (b)

600C, and (c) 750C for 2 h in air.

.


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A deconvolution of the light emission into five bands in t-

BT nanocrystals (heated at 750C for 2 h in air).

Emission spectra for

BaTiO3 nanopowders

after heating a sol-gel

precursor at (a) 400C,

(b) 600C, and (c)750C for 2 h in air.

Band positions, bandwidths, and relative

intensities in individual bands after

deconvolution of the observed light

emission in t-BT nanocrystals


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Schematic view of the energy band diagram proposed for t-BT

nanocrystallites as per the emission spectrum.


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Major Findings

Consists of two polymorphs of orthorhombic (o) and

tetragonal (t) structures in sample a.

Disordered phase converts to o-/t-BT at 600 oC

Average crystallites size 21-44 nm.

Single-phase t-BT transforms from o-BT at 750 oC

UV Emission in first two sample

Emission bands in both the ultraviolet and visible

regions follow the red-shift


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Luminescence from

doped Barium Titanate

S l l H d id M h d


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Stirring and heating at

5070 oC

Stirring for 2h

Stirring for 2-3 h


(1:1 volume ratio)


(C122H28O4Ti)

A transparent

solution prepared

Barium hydroxide

Ba(OH)2, 8H2O

Allowed to gel at

room temperature



Heating a



Iron(III) nitrate

[Fe(NO3)3, 9H2O]

Solgel Hydroxide Method


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XRD patterns for 2% Fe doped

BaTiO3 nanopowders A close-up

in the inset compares the shift in

(101) peak of sample (b) and (c).

Structural Properties of Fe-doped Barium Titanate

Sample Composition Heat treatment Structure D

t-BT (nm)

a 49BaO, 49TiO2, 2Fe2O3 4000C for 2hr o-BT-II -------

b 49BaO, 49TiO2, 2Fe2O3 6000C for 2hr o-BT-II, t-BT 16

c 49BaO, 49TiO2, 2Fe2O3 7000C for 2hr o-BT-II, t-BT 40

Heat-treatment schedule, crystal structure, and average D value


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A typical (a) TEM image and (b) Diffraction pattern taken from

specimen c heat-treated at 7000C for 2h. The diffraction rings inthe pattern (from center to edge) can be indexed as the (101), (111),

and (002) peaks of a tetragonal (P4mm) BT phase.

Transmission Electron Micrographs


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Photoluminescence spectra

Band positions, bandwidths, and relative

intensities in individual bands after fitted

with Gaussian curves.

Sample

Name

Position

(nm)

Intensity FWHM

(nm)

It

a 376.8 26.59 44.13 1249.18

421.3 42.18 33.53 1505.86452.1 24.15 24.71 635.41

485.3 24.81 27.01 713.50

526.1 10.99 24.87 291.15

619.8 11.54 47.91 588.69

b 388.2 26.23 61.88 1728.40

424.1 37.51 30.13 1203.39

457.4 52.15 37.26 2068.91486.7 64.89 13.62 941.35

522.3 36.94 45.23 1778.68

598.1 6.48 43.52 300.55

c 395.3 26.53 67.56 1908.57

424.7 28.03 28.77 858.49

456.9 49.93 34.43 1830.31

486.4 62.35 14.89 988.67522.0 34.96 41.36 1539.32

601.8 6.28 42.33 283.17

Luminescence Properties


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Schematic view of the energy band diagram of the specimens heated

at 700C for 2 h in air.


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300 350 400 450 500 550 600 650

0

20

40

60

80

100

120

Intensity(a

rb.units)

Wavelength (nm)

1NiBT4001NiBT600

1NiBT700

1NiBT800

1NiBT1000

300 350 400 450 500 550 600 650

0

10

20

30

40

50

60

70

80

90

100

110

120

130

Intensity(A

rb.units)

Wavelength (nm)

1FeBT4001FeBT600

1FeBT700

1FeBT800

1FeBT900

300 350 400 450 500 550 600 650

0

20

40

60

80

100

120

Intensity

(Arb.units)

Wavelength (nm)

1CeBT4001CeBT600

1CeBT700

140260


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300 350 400 450 500 550 600 650

0

20

40

60

80

100

120

Intensity

(arb.units)

Wavelength (nm)

1CeBT400

1FeBT400

1NiBT400

PureBT400

300 350 400 450 500 550 600 650

0

20

40

60

80

100

120

140

160

180

200

220

240

260

Intensity

(arb.unit)

Wavelength (nm)

1CeBT800

1FeBT800

1NiBT800

PureBT800


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Major Findings ot transformation process.

The average size 16 - 40 nm.

Band I EPR response originates due to isolated Fe3+ ions in low

symmetry site at low temperature.

Ti3+ defects stabilized by Fe3+.

The redshift of UV emission band

The blue band (452 nm) is seen to grow due to Ti3+ defects

stabilized by Fe3+

Same features observed for other dopant in BaTiO3.


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Dielectric and ferroelectric properties of nanometer sized BaTiO3

Sample Name

Annealed

Temperature

(oC)

Pellet Sintering

TemperatureTime (Hour)

BT-I 550 1000 (2h) 2h

BT-II 650 1000 (2h) 2hBT-III 750 1000 (2h) 2h

BT-IV 750 1000 (2h) 8h

BT-V 750 1000 (2h) 16h

St t l P ti f t i d


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Structural Properties of nanometer sized

Barium Titanate Barium Titanate

Sample

dhkl (nm) Ip h k l

Observed Calculated o-BT-II t-BT

BT-II 0.3995 0.4035 20 1 0 0

0.3715 0.3715 100 1 1 1

0.3213 0.3217 22 2 0 00.2848 0.2838 100 1 0 1

0.2627 0.2627 38 2 1 1

0.2322 0.2314 26 1 1 1

0.2148 0.2145 21 3 0 0

0.2018 0.2012 36 2 1 3

0.1939 0.1930 17 3 0 2

0.1795 0.1800 12 1 0 2

0.1643 0.1643 26 1 2 4

0.1642 0.1633 36 2 1 1

0.1418 0.1419 9 2 0 2

BT-III 0.3995 0.4035 16 1 0 0

0.3720 0.3715 100 1 1 1

0.2840 0.2838 100 1 0 1

0.2629 0.2627 Very low 2 1 1

0.2318 0.2314 27 1 1 1

0.2148 0.2145 Very low 3 0 0

0.2007 0.2017 23 2 0 0

0.1939 0.1930 Very low 3 0 2

0.1795 0.1800 7 1 0 20.1642 0.1634 27 2 1 1

0.1418 0.1419 13 2 0 2

BT-II

(Sintered

at

1000 oC

For 2h)

0.3995 0.3977 14 1 0 0

0.2840 0.2815 100 1 0 1

0.2318 0.2303 33 1 1 1

0.2007 0.1993 23 2 0 0

0.1795 0.1785 9 1 0 2

0.1642 0.1630 33 2 1 1

0.1418 0.1413 16 2 0 2

Assignments of observed dhkl values in o-BT-II and t-BTpolymorphs in a nanocoposite structure of sample:

X-ray diffraction pattern of BT showing the

transformation of o t BT after 2 h of

heating at (a) 6500C (b) 7500C.


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Dielectric constant Vs. Temperature at

frequencies ranging from 1 kHz to 1

MHz after calcinations at 650 0C and

sintered at 1000 0C for 2h.

Comparison ofr (At 100 kHz) varies with

temperature of all sample


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Variation of

Vs. T for all samples to fit Curie-Weiss law

The variation ofr (At 100 kHz)

with temperature of thenanocomposite after calcination at

6500C for determination of the W

value

Curie-Weiss law

=

The temperature dependence of parameters derived from CurieWeiss law fitting


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Temperature r (RT) r (TC) TC (0C) W (0C) tan

550o

C (2h) 245.64 270.19 133.02 138.4692 0.030913650 oC (2h) 248.35 294.84 134.17 97.4783 0.031107

750 oC (2h) 239.87 290.68 131.87 83.6314 0.032825

750 oC (8h) 249.88 296.64 134.17 82.7316 0.033694

750 oC (16h) 377.59 429.64 129.87 123.9224 0.018474

Temperature dependent ferroelectric properties of BaTiO3 prepared here.

The values are at f ~ 100 kHz.

Temperature T0 (0C) C ( 105 0C) Tm = Tdev - Tm (

0C)

550 oC (2h) 146.21 0.4833276 13.19

650 oC (2h) 147.96 0.6272306 13.79

750 oC (2h) 141.66 0.5107643 9.79

750 oC (8h) 148.02 0.6800408 13.84

750 oC (16h) 142.16 0.7860522 12.29

The temperature dependence of parameters derived from Curie Weiss law fitting.

The values are at f ~ 100 kHz

P l i ti M t


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Sample

Name

RemanentPolarisation Pr

(C/cm2)

SpontaneousPolarisation Ps

(C/cm2)

CoerciveField Ec

(kV/cm)

BT-I 0.3265 0.5714 9.0366

BT-II 1.1494 1.4942 14.5289

BT-III 0.6504 1.6260 7.0145

BT-IV 1.6279 3.7209 10.9363

BT-V 0.5681 1.1363 7.0350

Ferroelectric properties of BaTiO3 bulk ceramic

Polarization Measurement

Polarization-field hysteresis loops of pure

BaTiO3 bulk ceramic at room temperature


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Influence of cobalt ion doping on dielectric

behavior of barium titanate nanoparticles


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A sol gel route was used for the synthesis of BT nanoparticles.

Precursors: Barium acetate, Tetraisopropyl orthotitanate, Metal

nitrate and PVA

Ethyl alcohol:

acetic acid =

1:1

Tetra-isopropylorthotitanate

Stirred for 2 hrs

Solution A

Barium acetate

and distilledwater

Metalnitrate

Stirred for 2hrs.

Solution C

Solution B

Transparent

PVA

Cleargel

Dried and

calcinated

Crystallinephase of BT

Solgel Acetate Method

Structural properties of Co doped barium titanate of thin nanocrystals


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Structural properties of Co doped barium titanate of thin nanocrystals

X-ray diffraction patterns showing controlled t- BT to o- BT phase

transformation in a nano composite structure after doping with (b) 0.3

mole % Co ion (c) 0.6 mole % Co ion and (d) 1.6 Co mole % Co ion,comparing with (a) Undoped BT.

A close-up of view of the XRD patterns in the range 2 = 210 - 260 showing shifts

in (100)t, (111) and (102) peaks of o- BT specimens with (b) 0.3 mole % Co ion

(c) 0.6 mole % Co ion and (d) 1.6 Co mole % Co ion, comparing with (a)

Undoped BT after heating at 750

0

C for 2 h in air.

The lattice parameters, surface areas S0, and volume fraction () of o- BT(II) phase


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SpecimensLattice parameters (nm) S0

(nm2)

S0/V0

(nm-1)

a b c

Undoped BT 0.6393 0.5268 0.8824 2.7314 9.1935 9

0.3 mole% Co2+-BT 0.6395 0.5271 0.8825 2.7334 9.1879 38

0.6 mole% Co2+-BT 0.6412 0.5325 0.8875 2.7662 9.1294 64

1.6 mole% Co2+-BT 0.6405 0.5297 0.8865 2.7534 9.1566 52

Bulk BT 0.3987 0.5675 0.5690 1.5518 12.0574 --

p , 0, () ( ) p

after heating a polymer template at 750 0C for 2 h in air.

The value is reported for

the o-BT-II phase.

Sample

o-BT (II) t- BT(z =1)

D

(nm)

V

(nm3)

z

(g/cm3)

D

(nm)

V

(nm3)

(g/cm3)

Undoped BT 29 0.2971 4 5.214 28 0.06430 6.0230.3 mole% Co2+-BT 25 0.2975 4 5.207 26 0.06445 6.009

0.6 mole% Co2+-BT 21 0.3030 4 5.112 19 0.06456 5.999

1.6 mole% Co2+-BT 23 0.3007 4 5.151 23 0.06451 6.004

Bulk BT -- 0.1287 2 6.018 -- 0.06440 6.016

The average values of particle size (D), lattice volume V, lattice number z and density in both the

phases of o- BT(II) and t- BT in nanocomposite structure.

The values for the

bulk crystals are

reported fromliterature. The bulk o-

BT has a different

space group Amm2 than

the nanocrystals of a

Pnma space group.


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Transmission Electron Micrographs

(a) 0.6 mole % Co

ion doped BT(b) 1.6 mole % Co

ion doped BT

EDAX obtained using

High Resolution TEM

(a) 0.6 mole % Co ion

Particle size range 21-30 nm.

The matrix of the EDAX show strong

Ba, Ti, O, and Co peaks. No trace of

carbonate is evident.



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Doped BT possesses higher values of permittivity than undoped specimens.

Room temperature dielectric constant increases from a value of 160 to 375.

The presence of space charge polarization in the system is the reason behind the

enhancement of dielectric properties.

The ferroelectric paraelectric transition temperature decreases from 128 0C to a

minimum value of 43 0C for the specimens doped with 0.6 mole % dopant.

The coexistence of tetragonal and orthorhombic phase is the reason behind the

diffuse nature of the dielectric behavior.

The presence of secondary phase o-BT-II, have an important role in controlling the

dielectric properties of the specimens.


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l


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Conclusion

BaTiO3 in a specific Pnma orthorhombic crystal structure (o-BT-II) was

derived from basic structure of template over the Ba2+

and Ti4+

cations. Ti3+ defects are stabilized by Fe3+ in doped specimen. EPR spectra

support this statement.

Pure BT shows UV emission along with the emission in blue and yellow

range.

UV emission and EPR response from the specimens sintered at low

temperature may have a common origin. With doping, it is possible to synthesize nano sized BaTiO3 where the

ferroelectric phase stable at lower size. This will help to use the nano-BT

materials in memory devices.

List of Papers


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Published Papers:

1. P. Barik, T. K. Kundu and S. Ram, Light emission from ferroelectric barium titanate

nanocrystals,Philosophical Magazine Letters, 89, 2009, pp. 545555.

2. P. Barik, A. Jana and T. K. Kundu, Influence of Coion doping on tetragonalorthorhombic

polymorphic transformation and dielectric behavior in BaTiO3 nanoparticles, Journal of

American Ceramic Society , 94, 2011, pp. 21192125.

3. T. K. Kundu, A. Jana and P. Barik, Doped barium titanate nanoparticles,Bulletin of Material

Science, 31, 2008, pp. 501505.

4. T. K. Kundu, N. Karak, P. Barik and S. Saha, Optical properties of ZnO nanoparticles prepared

by chemical method using polyvinyl alcohol (PVA) as capping agent. International Journal of

Soft Computing and Engineering , 1, 2011, pp. 19-24.5. T. K. Kundu, S. Mishra, N. Karak and P. Barik, Effect of Ti4+ ions doping on microstructure and

dc resistivity of nickel ferrites, (communicated).

6. P. Barik and T. K. Kundu, Photoluminescence in Fe3+ ion doped barium titanate nanoparticles,

(communicated).

Workshop/Conference Attained:

1. Doped BaTiO3nanoparticles, T. K. Kundu, A. Jana and P. Barik, Review and Coordinationmeeting on Nanoscience and Nanotechnology held at ARCI-Hyderabad (INDIA), 2007.

2. Photoluminescence of Doped Nano Barium Titanate, T. K. Kundu and P. Barik,International

Conference on Nanotechnology & Medical Sciences (ICNAMS-2010), 21th-23th October, 2010.

3. Optical and Electrical Properties of CdS Quantum Dots embedded in Barium Titanate Matrix,

P. Barik and T. K. Kundu, 13th National Symposium in Chemistry (NSC-13), 4th-6th February,

2011.

A t f th i


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Arrangement of thesis

1. Introduction

2. Method of preparation and experimental techniques3. Light emission from ferroelectric pure barium titanate

nanocrystals

4. Photoluminescence in Fe3+ ion doped barium titanate

nanoparticles

5. Light emission from Ni, Ce doped barium titanate nanoparticles6. Dielectric properties of nanometer sized Barium Titanate

7. Influence of Cobalt ion Doping on TetragonalOrthorhombic

Polymorphic Transformation and Dielectric Behavior of Barium

Titanate Nanoparticles

8. Conclusion


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I take this opportunity of expressing my deep sense of gratitude,

regards and appreciation to my supervisor Dr. Tapas Kumar

Kundu for proposing the topic of the present Ph.D. thesis and for

introducing me to the magnificent field of research in Nanoscience

and Nanotechnology. I convey my heartfelt thanks to Dr. A. Jana and Mr. N. Karak,

research scholar of our group.

ACKNOWLEDGEMENTS


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Equipment for investigation nanoparticles


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q p g p

General Purpose TEM

JEOL 200CX

JEOL 6700F Ultra High Resolution

Scanning Electron Microscope

Back

Electron Paramagnetic resonance

Spectroscopy

H i C t llit Si D fi d


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How is Crystallite Size Defined Usually taken as the cube root of the volume of a crystallite

assumes that all crystallites have the same size and shape For a distribution of sizes, the mean size can be defined as

the mean value of the cube roots of the individual crystallite volumes

the cube root of the mean value of the volumes of the individual crystallites

Scherrer method (using FWHM) gives the ratio of the root-mean-fourth-power to the root-mean-square value of the thickness

Stokes and Wilson method (using integral breadth) determines thevolume average of the thickness of the crystallites measuredperpendicular to the reflecting plane

The variance methods give the ratio of the total volume of thecrystallites to the total area of their projection on a plane parallel tothe reflecting planes

Back

Remember Crystallite Size is


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Remember, Crystallite Size is

Different than Particle Size

A particle may be made up of several different

crystallites

Crystallite size often matches grain size, but there are

exceptions

Back

Profile Functions


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Profile Functions Diffraction peaks are usually the convolution of Gaussian

and Lorentzian components Some techniques try to deconvolute the Gaussian and

Lorentzian contributions to each diffraction peak; this is

very difficult

More typically, data are fit with a profile function that is apseudo-Voigt or Pearson VII curve

pseudo-Voigt is a linear combination of Gaussian and Lorentzian

components

a true Voigt curve is a convolution of the Gaussian and Lorentziancomponents; this is more difficult to implement computationally

Pearson VII is an exponential mixing of Gaussian and Lorentzian

components

Method of preparation pure Barium titanate


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Method of preparation pure Barium titanate

Sol-gel processing

Hydrolysis:

4

+ 2

4

+ Condensation:

4 + 4 4 1 4 1 + 2

Hydrolysis and condensation reactions are both multiple-step processes,

occurring sequentially and in parallel. Each sequential reaction may be reversible.

Aqueous or alcohol-based Involves use of molecular precursors, mainly alkoxides, Alternatively, metal formates Mixture stirred until gel forms Gel is dried @ 100 C for 24 hours over a water bath, then ground to a powder Powder heated gradually (5 C/min), calcined in air @ 500 1200 C for 2 hours

Allows mixing of precursors at molecular level Better control High purity Low sintering temperature High degree of homogeneity Particularly suited to production of nano-sized multi-component ceramic powders

Back

Si ff t f B i Tit t


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The dielectric properties of BaTiO3 are found to be

dependent on the grain size.Large grained BaTiO3 (1m) shows an extremely high

dielectric constant at the Curie point.

This is because of the formation of multiple domains in a

single grain, the motion of whose walls increases thedielectric constant at the Curie point.

For a BaTiO3 ceramic with fine grains (~1m), a single

domain forms inside each grain.

The movement of domain walls are restricted by the

grain boundaries, thus leading to a low dielectric constant

at the Curie point as compared to coarse grained BaTiO3.

Size effect of Barium Titanate

Back


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Introduction

toNanoscience

Back


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A part of science that studies small

stuff.

Its not biology, physics or chemistry. Its

all sciences that work with the very

small.

T d


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Top-down

Nanotechnology is the next step

after miniaturisation.

microelectronics

nanoelectronics


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Ultimate Nanotechnology would be to build atthe level of one atom at a time and to be able to

do so with perfection.

Arranged one way, atomsmake up soil, air and

water. Arranged another

way they make up

strawberries or smoke.

Bottom-up


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NanoScience

Nanotechnology

Physics

Material

Science

Engineering

Chemistry

Biology

Medicine


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Atomic (electronic) structure
http://cst-www.nrl.navy.mil/lattice/struk/fcc.html


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Atomic (electronic) structure

Molecular structure

Physical characteristics Electrical characteristics Biological characteristics

ATI Radeon HD 3870 X2 Graphics Card Electronics
http://www.photovault.com/Link/Cities/Midwest/Oklahoma/show.asp?tg=CMODVolume01/CMOD01_071http://en.wikipedia.org/wiki/Image:Types_of_Carbon_Nanotubes.pnghttp://www.google.com/imgres?imgurl=http://czechabsinthe.files.wordpress.com/2007/04/molecule.jpg&imgrefurl=http://czechabsinthe.wordpress.com/2007/05/19/lucid-pre-ban-absinthe/&h=335&w=349&sz=13&tbnid=aa6-teA62GwJ::&tbnh=115&tbnw=120&prev=/images?q=images,+molecule&hl=en&usg=__umZ5T_DeOwRji3LR4NUChbRqerc=&sa=X&oi=image_result&resnum=2&ct=image&cd=1http://www.google.com/imgres?imgurl=http://media.nasaexplores.com/lessons/02-060/images/atom.jpg&imgrefurl=http://nasaexplores.com/show_58_teacher_st.php?id=030107160237&h=255&w=296&sz=19&tbnid=kBqOZyr24HUJ::&tbnh=100&tbnw=116&prev=/images?q=images,+atomic+structure&hl=en&usg=__gVM_77HQ3D5fTb0I-4eut92dMhE=&sa=X&oi=image_result&resnum=6&ct=image&cd=1http://www.google.com/imgres?imgurl=http://hsc.csu.edu.au/engineering_studies/transport/3059/images/figure1.gif&imgrefurl=http://www.hsc.csu.edu.au/engineering_studies/transport/3059/manuf_polymer.html&h=141&w=434&sz=25&tbnid=rnP6lD_K5MsJ::&tbnh=41&tbnw=126&prev=/images?q=images,+polymer+structure&hl=en&usg=__-Tpt4sw9A28UhpAW0BoOdd8Bn7Y=&sa=X&oi=image_result&resnum=3&ct=image&cd=1http://cst-www.nrl.navy.mil/lattice/struk/fcc.htmlhttp://en.wikipedia.org/wiki/Image:AcetaldehydeDehydrogenase-1NVM.png


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pennnet.com

Intel 45nm Silicon Wafer Processor

gizmodo.com

ziffdavisinternet.com

Planet82 SMPD Image Sensor

(Flash-less Photography)

videolan.org

Xbox 360

Samsung.com

16Gb NAND Flash Memory

Nano Silver Spray Benny the antimicrobial bear


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tradenote.net

Nano TiO2 Air Purifiers

sharp.net

Premium Top Mount Refrigerator

KLENZ.NU

Clean Shoe Locker

daewoo-electronics.de

Daewoo Washing Machine

freeamerican.comdiytrade.com

Antibacterial Kitchenware

Nano Phytoncide Toothpaste

tootoo.com

nanowerk.com

Nanotea

overstock.com

Cosmetics/beauty


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/ y

BIONOVA Cosmetics

beautymecca.blogspot.com

segaei.com

Cosil Nano Beauty Soap

Green Yarn G-moist soft cloth mask

greenyarnstore.com

essentialgearguide.com

Infiniti Nano Silver Strengthenertradenote.net

Nano Anti Aging Cream

alibaba.com

Nano Salon Pro 2000Chemical-Free Sunscreen SPF 15

Emergency Filtration Products NanoMask Antimicrobial nano-bagMiscellaneous


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Ain Supplio Pencil (fragrence pencil lead)

Acticoat Wound DressingsAntibacterial Lock

Deletum 5000 Anti-graffiti paint

nanotechproject.org

DeWalt Cordless Power-tool Set

atr.com

Plastic Beer Bottlesflupharmacy.com

nanotechproject.org

Dog Gone Smart bed

techxpress.net

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Presentation 14-08-2011 VI

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