New Folderch1

7/25/2019 New Folderch1

1/79

CHAPTER 1

INTRODUCTION

1


2/79

1.1. Introduction

First chapter is about brief introduction of nanotechnology, its application, nanowires, nanotubes

and nanoparticles, also detailed description about Iron Aluminum oxide, its all properties,

crystal structure and synthesis method.1.2.Nanotechnology and science society

Nanotechnology has ability to obsere measure and change things at nanometer leel. A length

of nanometer is !I i"e 1#"$ %1, 2&. 'he technology which measure thing at nano leel is

Nanotechnology .Nanotechnology has ast present and future applications in our society and in

science. It is use in different fields such as medical field, agriculture, military applications,

sporting goods, car paints and car waxes, antibacterial cleanser, medical bandages, apparel

industry, sun screens and cosmetics, organic light emitting displays or ()*+! %&, diagnostics,noel drugs, lightweight materials, adance computing, increased situation awareness, powerful

munitions, energy and water%-&. It is chec and explain of material at the nano scale haing

dimensions between 1 to 1## nanometer %/&. It enables wide range of distinctie applications

which might be not possible if woring with materials of si0e een of single atoms or molecules.

esearchers looing to now about the basic property called nanoscience which paying attention

on effectie use of the properties called nano engineering. At nano leel, nanotechnology

inoles imaging, measure, modeling, and manipulate of material.

Nanotechnology is progressing rapidly nowadays %"&. esearchers are learning ast amount of

nowledge about health benefits. 'he origin of nanotechnology is found to the ability of

innoatie deelopments towards all science fields. 'he potential applications of nanotechnology

is too immense and arious, but one of the greatest achieement of nanotechnology will be in the

field of effectie medical dealing %1, 3"1#&. 4y using nanotechnology, we can enhance the

medical 5uality including, the deelopment of nanoparticles for drug, gene deliery and

diagnostics. 4y using these technologies we are able to mae accurate diagnosis.

1.2.1 History of Nanotechnology

'he width of hair of animal is about 6#,### nm while the width of a human blood cell is 3###

nm. !i0e of atoms is less than 1 nm, whereas many particles and some proteins are between 1 nm

and larger %11&. Its hypothetical basics were first introduced in 1$/$ by ichard Feynman,

2


3/79

7theres abundance of room at the underside8 .'hen 7nanotechnology8 term is used by Norio

'aniguchi to discuss the materials ability to engineer precisely at the nano scale. Initially

miniaturi0ation was done by electronics industries that focus to create tools to deelop smaller

electronic deices by using silicon chips. In 1$3#s, techni5ue of e"beam lithography was used to

create ery small nanostructures at I49 in :!. 'hen, in 1$61, ;. 4inning and


4/79

nanomaterials. Nanostructures materials may be grouped under nanoparticles, Nano

intermediates and Nano composites. 'hey may be in or far away from thermodynamic

e5uilibrium.

1.-. Nanoparticles

article of less than 1##nm in diameter are nown as nanoparticles. Nanoparticles continue

liing widely in todays timeB for instance as the resulting product of olcanic and photochemical

actiity, and created by algae and plants. Nanoparticles attain great intention because of their

uni5ue properties as compared to bigger particles of lie materials. Nanoparticles hae a range of

applications lie textiles, new cosmetics and paints. Nanoparticles can also be agreed into layers

on surfaces, owing to large surface area and the resulting enhanced actiity nanoparticles find

wide range of applications as catalysts.

Nanoparticles are lesser cluster of atoms about 1 to 1##nm long. Nanometer is billionth of meter

or 1#"$m. Nanoparticles are superior or greater than indiidual atom or molecule but are smaller

than bul solid.


5/79

Figure 1.1: Diagram show schematic representation of different sizes [13]

!econd phenomenon occurs only in metals and semiconductors it is called si0e 5uanti0ation and

arises because si0e of nanoparticles is comparable to de"4roglie waelength of its charge carrier

Di"e electrons and holesE. +ue to spatial confinement of charge carriers, edge of alance and

conduction band split into discrete, 5uanti0ation and electronic leel. 'hese electronic leels are

similar to those in atoms or moles as shown in fig 1.2%1&.

5


6/79

Figure 1. 2: In diagrams, conduction band and a!ance band in so!id, "anopartic!es and atom

state of semiconductor #!eft$ and a meta! #aboe$ are compared [13].

6


7/79

It can be seen here again that nanoparticles represent a state of matter in transition state between

bul solids and indiidual atom.

1./. Nanowires

A nanowire is defined as a wire of dimension of few nanometers. At nanometer leel uantum"

mechanical effect is dominated so these wires are also called 5uantum wires.

1.%.1 Ty#es of Nano&ires

G 9etallicD Ni,t and Au nanowiresE

G !emiconductor D In,!i and ;aN nanowiresE

G Insulator D!i(2and 'i(2nanowiresE.

(rganic or inorganic molecular nanowires can be produced by repeating molecular unit. 9ostly

nanowire has large aspect ratio of 1### or more. Nanowires hae some uni5ue properties that are

not rated to be obsered in bul material since at Nano scale leel these shows 5uantum

confinement effect of electrons but in bul scale these materials shows continues energy leel.

4ul material hae large conductiity as compare to nanowire this is because when the width of

wire is below the free electrons mean free path of the bul material there exist scattering from

the boundaries of wires. Nanowires also show many strange electrical properties due to 5uantum

si0e effect.

1.. Nanotubes

For one element hollow cylindrical or toroid molecule are made. Nanotechnology is inestigated

for uses in nanotubes. 'hey hae good thermal conductiity and extremely strong material. 'hey

hae possible use in Nano"electronic and Nano"mechanical deices. In seeral fields the

researcher and companies are using the properties of nanotubes. ?hen the other molecules are

attached to the carbon nanotubes their electrical resistance aries. 9ost of the =ompanies are

7


8/79

using property to deelop sensors which will detect chemical apors for example carbon

monoxide or biological molecules. +ue to 5uantum confinement effect in 2+, semiconductor

nanotubes reeal electronic and optical properties.

1.3. Iron

Iron is a chemical element of periodic table located in the eighth group and is represented by the

symbol Fe. 'his metal is present in first transition element series %1/&. It is the fourth most

common element present in earths crust. Iron exists in wide range of oxidation states that ranges

from H2 to H. 'he most common state is H2 and H. Iron is ery reactie with oxygen and

water. Fresh iron appears with silerish grey surface but it oxides with normal air and form ironoxide which is commonly nown as rust. ?hen impurities, most commonly carbon is added into

iron by smelting process, then it conerts into steel. !teel is 1## times harder than pure iron.

=hemical compounds of iron are also of wide use. Fig 1. below shows the physical appearance

of ironB

Figure 1.3 ph%sica! appearance of Iron meta! [21].

8


9/79

1.'.1. Physical #ro#erties of Iron

'he maCor physical properties of iron as gien below in the table 1.1B

&ab!e 1.1 'h%sica! properties of Iron.

=olor !iler"gray metal

9alleability =apable of being shaped or bent

+uctility *asily pulled or stretched into a thin wire

)uster


10/79

Isotopes of Iron are gien below in the table 1.

&ab!e 1.3 isotopes of iron.

Isotope Atomic mass Natural abundance

D E


11/79

Figure 1.) *od% centered and Face centered cr%sta! structure of Iron [22]

1.'.%. Uses of Iron

Iron is one of the most widely used metal. Its extensie use in industry is due to its low cost andhigh strength. It is used in industry in maing arious tools, metallurgical instruments and auto

mobiles. Iron plays a ital role in the field of biology. 9any complexes are formed by iron with

oxygen in hemoglobin and hemoglobin in human body. Adult human hae about one eighth of a

once that is about ./g of iron in their body. I+A that is Iron deficiency anemia is due to

deficiency of iron in human blood.

1.6. Aluminum

Aluminum is a silery white metal in its pure form. Its symbol is Al and haing atomic number

1. It is soft in nature and ductile element. After oxygen and silicon it is the most abundant

element found in the earths crust. Aluminum is nontoxic and nonmagnetic element. It is

use for decoratie purposes.

11


12/79

1.).1. Physical #ro#erties of al$(in$(

&ab!e 1. ) ph%sica! properties of a!uminum

Atomic mass 2.$61/- g.mol"1

*lectro negatiityaccording to auling 1./+ensity 2.3 g.cm"at 2# M=

9elting point #.- M=

4oiling point 2-3 M=

ander ?aals radius #.1- nm

Ionic radius #.#/ nm

Isotopes

Artificial isotopes 1

*lectronic shell 1s2 2s2 2ps2 p1

*nergy of first ioni0ation /33.- >.mol"1

*nergy of second ioni0ation 161.1 >.mol"

*nergy of third ioni0ation 23--.1 >.mol"1

!tandard potential " 1.3

1.).2. Che(ical #ro#erties of Al$(in$(

(ne of the most useful properties of aluminum is that in moist air it reacts slowly with oxygen

and forms a thin layer of aluminum oxide on the surface of the metal that preents the element

from further reaction and corrosion. 'his thin layer of aluminum oxide can easily be seen on

aluminum outdoors. Aluminum is a highly reactie metal. It reacts with arious hot acids. It also

reacts with hot water and alalis. 'he powder form of aluminum catches fire 5uicly as it is

highly flame able.

1.$. Aluminum oxide'he common name of aluminum oxide is Alumina. It is basically the chemical compound of

oxygen and aluminum and represented by the symbol Al2(-. Aluminum oxide is commonly used

to produce aluminum metal due to its high melting point and hardness. %1&. 'he physical

appearance of alumina is shown in fig belowB

12
http://www.lenntech.com/Periodic-chart-elements/atomic-mass.htmhttp://www.lenntech.com/Periodic-chart-elements/electronegativity.htmhttp://www.lenntech.com/Periodic-chart-elements/density.htmhttp://www.lenntech.com/Periodic-chart-elements/melting-point.htmhttp://www.lenntech.com/Periodic-chart-elements/boiling-point.htmhttp://www.lenntech.com/Periodic-chart-elements/vanderwaals.htmhttp://www.lenntech.com/Periodic-chart-elements/ionization-energy.htmhttp://www.lenntech.com/Periodic-chart-elements/electronegativity.htmhttp://www.lenntech.com/Periodic-chart-elements/density.htmhttp://www.lenntech.com/Periodic-chart-elements/melting-point.htmhttp://www.lenntech.com/Periodic-chart-elements/boiling-point.htmhttp://www.lenntech.com/Periodic-chart-elements/vanderwaals.htmhttp://www.lenntech.com/Periodic-chart-elements/ionization-energy.htmhttp://www.lenntech.com/Periodic-chart-elements/atomic-mass.htm


13/79

Figure 1.+ ph%sica! appearance of a!uminum oide.

1.*.1. Physical #ro#erties of al$(in$( o+i,e

'he physical properties of alumina are shown in table 1./B

&ab!e 1.+ ph%sica! properties of a!uminum oide

9olecular formula Al2(-

9olar mass 1#1.$ g molO1

Appearance white solid

(dor (dorless

13
http://en.wikipedia.org/wiki/Molecular_formulahttp://en.wikipedia.org/wiki/Molar_masshttp://en.wikipedia.org/wiki/Odorhttp://en.wikipedia.org/wiki/Molecular_formulahttp://en.wikipedia.org/wiki/Molar_masshttp://en.wikipedia.org/wiki/Odor


14/79

+ensity .$/P-.1 gQcm

9elting point 2,#32 M= D,32 MFR 2,-/ @E

4oiling point 2,$33 M= D/,$1 MFR ,2/# @E

!olubilityinwater Insoluble!olubility Insoluble in diethyl ether

practically insoluble in ethanol.

'hermal conductiity # ?SmO1S@O1

1.*.2. Che(ical #ro#erties of al$(in$( o+i,e

G Aluminum oxide is insoluble in water.

G It reacts with acids. 4ases and alalis.

G It has high melting point.

G It is beneficial as abrasie due to its hardness

G It also acts as electrical insulator.

G Aluminum oxide preents the metal aluminum from further corrosion.

1.*.!. Crystal str$ct$re of al$(in$( o+i,e

'he most common crystalline form of Al2(is nown as corundum. 'he crytal structure of

alumina exists in different modifications. 'he three most important crystalline forms of

alumina areB

G Alpha DstableE

G @appa DmetastableE

G ;amma DmetastableE

14
http://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Melting_pointhttp://en.wikipedia.org/wiki/Boiling_pointhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Melting_pointhttp://en.wikipedia.org/wiki/Boiling_pointhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Solubilityhttp://en.wikipedia.org/wiki/Thermal_conductivity


15/79

a. Al#ha al$(ina

It is the only stable state of alumina at all the temperatures. 'he structure of alpha alumina is

trigonal and it is explained as A4A4 stacing of oxygen planes along c direction and aluminum

ions are present at 2Q of the octahedral interstitial position.

Figure 1.- chematic drawing of the first !a%er in the a!pha a!umina structure [1/]

-. a##a al$(ina

@appa alumina shows the orthorhombic structure. In this structure oxygen is closely paced in

A4A4 stacing arrangement along the c direction. In this structure T of the aluminum atomsare present at tetrahedral position and remaining U occupy the octahedral position.

15


16/79

Figure 1.0 chematic drawing of the first two !a%ers in the appa a!umina structure. ctahedra!

! ions are b!ac, tetrahedra! are gre% [1/].

c. /a((a al$(ina

'he structure of gamma alumina is cubic. In this structure oxygen is present in stacing position

of A4=A4= and is based on fcc structure. 'his type of structure is often referred as defect

cubical spinel structure where acancies are present at cation positions. In this structure

aluminum ions occupy both positions, octahedral and tetrahedral.

Figure 1.4 chematic drawing of the first two !a%ers in the gamma a!umina structure [1/].

1.*.". A##lications of al$(in$( o+i,e

16


17/79

Aluminum oxide is one of the most ersatile oxides and it has wide applications in arious fields.

As aluminum oxide is a ery good electric insulator so it is used as a substrate for integrated

circuits. It also uses as a tunnel barrier for the fabrication and synthesis of super conducting

deices such as single electron transistor. Aluminum oxide is also used in the manufacturing of

spar plug insulator. 'he maCor applications of aluminum oxide are as underB

G Filter

G =atalysis

G urification

G Abrasie

G aint

G =omposite fiber

1.1#. 'echni5ues for the synthesis of nanostructures

'here are two approaches for synthesis of the nanomaterial. (ne is the 7top"down approach8 and

the second one is the 7bottom"up approach8.

1.10.1. To#,o&n A##roach

In this approach the wor is started from the top Dfrom the bul materialE and ended at the bottom

DnanomaterialE. !o top"down means from top DlargerE to bottom DsmallerE. 'his approach has the

same trend as for maing the statue made of a stone. For exampleR the maing of a statue is

started from the bul leel or a big piece of a stone, in the same way in the top"down approach,

bul material is taen at the starting. 'hen the caring and cutting processes are inoled to

achiee desired shape. 'he arious top down techni5ues are as underB

G Nanolithography

G +ry etching techni5ues

G Anodi0ation

1.10.2. Botto($# A##roach

17


18/79

'his is the second one approachR in this approach the wor is started from the bottom Dat the

atomic leelE and ended at the top DnanomaterialE. 'he bottom"up means from the bottom

DsmallerE to the top DlargerE. In this approach, a nano"metric structure is taen then this structure

is assembled without any external manipulation. 'his method is nown as self" assembly. 'he

arious bottom up techni5ues use for the synthesis of nanostructures are as underB

G !ol"gel processing

G =hemical apor deposition

G !elf"assembly and bio assisted synthesis

G )aser pyrolysis

G *lectrochemical depositionQ electroplating

G !praying synthesis

'he fig 1.$ shows the pattern of both the techni5ues for the synthesis of nanomaterial.

Figure 1./ top down and bottom up approaches [25].

1.10.!. Electro,e#osition techni$e

*lectrodeposition is the process of deposition of metals. It is the process in which electric currentis re5uired to reduce cations of the desired material from the solution and to coat the desired

material on the conductie substrate in the form of thin film. *lectrodeposition is used for the

ariety of applications in nanotechnology, microelectronic optics and related fields. It is also

widely used in many industrial applications for the manufacturing of Cewelry, tools, electronic

deices automobile and toy industry. %13&

18


19/79

1.10.". Ty#es ofelectro,e#osition

'here are two types of electrodeposition

*lectroplating

*lectro"less plating

Electro#lating

In electroplating process, we place our substrate in a li5uid solution which is nown as

electrolyte. 4y applying the electrical potential between a conduction area on the substrate and a

counter electrode in the li5uid, a chemical process occurs and as a result a layer of material

deposit in the conductie substrate.

Electroless #lating

In this process, a complex chemical solution is used in which deposition happens spontaneously

on any surface which forms a high chemical potential with the solution.

'he main difference between the two techni5ues is the re5uirement of external applied electric

oltage. In eletropalting we need an external applied oltage but in electro"less plating there is no

such re5uirement. 'he electroplating process is only for conductie substrates. 4y using this

techni5ue we can grow the films with the thicness ranges up to tens of micrometer. ?hereas,

the electro"less plating process can be used for the conductors and dielectrics but in this

techni5ue it becomes difficult to control the thicness and uniformity of the film%16&

1.10.%. Benefits of electro,e#osition

'his process is considered to be best for the deposition of metals. It is less expensie techni5ue

for the formation of well"defined nanostructure as compared to the other acuum based

techni5ues. 4y using this techni5ue we can grow the films with the thicness ranges from

19


20/79

1micrometer to 1## micrometer. 'he applied external electric potential helps to control the

thicness and uniformity of the deposited film.

1.10.3. Re$ire(ents for s$ccessf$l electro,e#osition

'he basic re5uirement for the successful deposition of material ia electrodeposition is as underB

;ood adhesion of resist is re5uired because the plating presses against the resist during selectie

area plating.

=leaning of substrate, solution and e5uipment is another basic re5uirement because a little

amount of impurity can affect the 5uality of deposited film.

'he plating solution has to be compatible with the substrate and the resist because arious

plating solutions are caustic and reacts with the substrate and the resist.

1.10.'. 4or5ing #rinci#le of electro,e#osition

*lectrodeposition is also termed as electroplating. 'his method is referred to as bottom up

techni5ue for the synthesis of nanostructures. *lectrodeposition is mainly use for the synthesis of

nanostructure. 4y using this techni5ue one can obtain designs with high density and high aspect

ratio. As in the lithographic techni5ue, electrodeposition also re5uires polymer mas from which

the metal is deposited. *lectrodepostion build the structure atom by atom and do not show theproblem of showing near interfaces and edges, as in the other techni5ues such as ion milling, I*

and isotropic etching. 'his techni5ue is restricted to the electrically conductie materials. 4y

using this method we can synthesis nanostructures with thicness haing range from V1Wm to

J1##Wm. In this process a suitable substrate is placed in the li5uid solution nown as electrolyte.

+uring electrodeposition process we use electric current to reduce the cation of the desired

material present in the solution. As a result of this current these cations coats as a thin film of that

material on the conducting substrate surface. 'he thicness of the thin film on the substrate

depends on the timing of the plating. 'he longer the obCect remains in the operating plating bath

the thicer will be the layer of the electroplated thin film. 'he arrangement for the

electrodeposition process is shown in the fig below.

20


21/79

Figure 1.15 etup for e!ectrodeposition [14].

1.10.). Pro#erties of ,e#osite, fil(

'he deposited film should hae some properties that are listed below.

6 A,hesion7

'he one of the maCor re5uirement of the electroplated film is good adhesion. 'he adhesion is

mainly depends on the substrate. For good adhesion the cleaning of the substrate should be

done properly. It should be free of any surface films. 'he substrate and the deposited film

should interfuse with interlocing grains to gie a smooth surface.

6 8echanical #ro#erties7

9echanical properties of the electrodeposited film onto the substrate mainly rely on the

amount and the type of the growth inhibiting substances on the surface of the cathode. 'he

reason we use growth inhibiting substance is to obtain fine grain structure of the

21


22/79

electrodeposited film. !o that the grain boundaries act as the obstacle to dislocation motion.

As a result the deposited film has high yield strength and hard surface.

6 Brightness7

4rightness of the electroplated film is re5uired for decoration purposes. 'he brightness of the

film mainly relies on the surface finish of the substrate material. In order to obtain a thicer

bright deposited film, an additional agent has to be added in the plating solution. 'hese

additional agents eliminate the protrusions. ?idely used additional agents includes organic

compounds such as lactose, dextrose,tartarates and formaline.

1.10.*. A##lications of electro#lating

'he application of electroplating is mainly in the following four fieldsB

6 Decoration

'his application includes forming a layer of an expensie metal on another metal base for

the decoration purpose. It is used in the formation of Cewelry, furniture, hardware and

table ware.

6 Protection

'o sae material from corrosion. For example by coating chromium layer on auto

mobiles parts, by coating cadmium and 0inc layer on electrical parts, Nuts, tools and

screws.

6 Electrofor(ing

'his application inoles the manufacturing of record stampers, screens, moulds and

dies.

6 Enhance(ent

'his application inoles the coating of a material which has better electrical and thermal

conductiity as well as reflectiity and solders ability.

22


23/79

1.10.10. 9actors affecting the electro,e#osition techni$e

'he factors that influence the coating 5uality and 5uantity in electro"deposition techni5ue are as

belowB

G =urrent efficiency

G =urrent density

G *lectrode potentials

C$rrent efficiency

According to Faradays laws, the amount of chemical charge at an electrode is proportional to

total amount of electricity passing from electrode. =urrent efficiency can be define as total

percentage of electric current that is passing through the electrolytic cell for the re5uiredchemical reaction. 'he current efficiency proided to cathode reaction is nown as cathode

efficiency and that proided to anode is termed as anode efficiency.

C$rrent ,ensity

'he current per unit area of electrode is termed as current density and it is calculated in amperes.

'he current density largely affects the properties of the coated film. =urrent will moe at the

edges in order to minimi0e the solution resistance. For uniform current distribution the amount of

current has to be same at all point of the electrodes.

Electro,e #otential

'he electric potential difference between the reference electrode and electrode is nown as

electrodes potential. It is always referred to as an arbitrary 0ero point.

23


24/79

1.11 )ayout of the 'hesis

In first chapter, I briefly introduce nanotechnology, its application, nanowires, nanotubes and

nanoparticles, also detailed description about element which I choose for my research wor. I

also described the properties, crystal structure and synthesis methods. 'hesis layout is alsoincluded in this chapter.

In the second chapter, detailed description of the methods and process for the synthesis were

gien. Also, mentioned the preious wor done by arious techni5ues.

'hird chapter includes the experimental detail about the synthesis. 'he techni5ues used for the

characteri0ation were also described. 'hird chapter also describes the preparation method of Iron

Aluminum (xide.

'he results of arious characteri0ation techni5ues and the discussion of these results are gien in

this chapter. Also the conclusion on the basis of these results was in chapter -.

24


25/79

1.12. eferences

1. Nanotechnology 4asic !cience and *merging 'echnologies 4y 9. Nilson,@.@annangara,

9. !immons and 4. aguse, =hapman and


26/79

1. Nanomaterials and nanostructures by l. =ostlow and A. . +omi, 4ard, ). Faulner. *lectrochemical methods and applications, 2nd edition, >ohn

?iley and sons, New [or, 2##1

13. '.(saa, '.[ooshima, +.!hingha, @.Imai, @.'aashima, 7electrochem. !olid"!tate

)ett8, /"//, 2##

16. httpBQQelectroplating.wiispaces.com.

1$. httpBQQfy.chalmers.seQVf1#mhQ=+Qaluminaintro.html.

2#. 9. Imran, 7'he !ynthesis and =haracteri0ation of 'i(2Nanoparticles8. =entre of solid

state physics, :niersity of the unCab.

21. httpBQQgoldsileralert.blogspot.comQ2#11K#2K#1Karchie.html.

22. httpBQQ0appnews.comQseries"2.html.

26
http://electroplating.wikispaces.com/http://fy.chalmers.se/~f10mh/CVD/aluminaintro.htmlhttp://goldsilveralert.blogspot.com/2011_02_01_archive.htmlhttp://zappnews.com/series3-2.htmlhttp://zappnews.com/series3-2.htmlhttp://electroplating.wikispaces.com/http://fy.chalmers.se/~f10mh/CVD/aluminaintro.htmlhttp://goldsilveralert.blogspot.com/2011_02_01_archive.htmlhttp://zappnews.com/series3-2.html


27/79

CHAPTER 2

:iterat$re Re;ie&

27


28/79

2.1. Introduction

'his chapter is based on the literature reiew of preious papers that has been written on the

synthesis of iron aluminum oxide nanostructures with arious techni5ues. In my experimental

wor 7'op down approach8 has been used for the synthesis iron aluminum oxide nanostructures.

?e hae use electro"deposition techni5ue in our experiment. Iron and alumina is obtained fromdifferent sources of iron and aluminum.

2.2 literature reiew

aesano >r. et al. %1& reported the synthesis of Fe.Al2(nanocomposites by Arc melting

pellets of iron and aluminum powders. In this experiment two different nominal grades of

alumina was used for the synthesis of nanocomposites. 'he samples were characteri0ed by x"ray

diffractometry, spectroscopy and magneti0ation. 'he results of the samples showed that spinel

Fe. Al2(and metallic iron were formed by this melting process. It could be seen from the results

that by increasing the iron contents in the initial powder, the chances of hercynite reaction also

increased. ?hen the arc melted sample was annealed at 12##M= in hydrogen atmosphere, it

showed a reduction in hercynite and phase separation of metallic iron. 'hey also found that more

used of pure alumina, in started powder reduced the fraction of iron nano crystals.

28


29/79

radhan et al. %2& reported the synthesis of nancomposites of iron incorporated

mesoporous Al2(. 'hese nanocomposite were proed an efficient photo catalyst for hydrogen

production under isible light. 'hey used the sol"gel process for the formation of

nanocomposites which is then followed by wetness impregnation method. 'hese nanocomposites

were proed to be actie photo catalyst for the eolution of hydrogen energy from water in the

presence of sacrificial agent. 'he factors that play part in the splitting of water are band gap

energy, small particle si0e, high surface area and mesoporous nature. 'he +:"is spectra

measured the band gap. '*9 is used to ealuate the particle si0e. 'he material is also

characteri0ed by x"ray diffraction. 'he small particle si0e that is about -3.$/nm, isible light

actie band gap 1.$# e were the factors that contributed in the high hydrogen production ability

of Fe.Al2(. 'he mesoporus Al2(was synthesi0ed by using sucrose as a substrate. 9esoporous

Al2("9=9"-1 was synthesi0ed by incorporating meso" Al2( to the 9=9"-1. Iron withdifferent weight was then added in Al2("9=9"-1 by using wetness impregnation method.

Ferrous !ulphate was used as the source of iron. After this the iron added Al2("9=9"-1

nanocomposites were calcined at ##M= for h.

!hinde et al. %& reported the synthesis of aluminum doped Fe2( nanoparticles. 'hey

studied their physical and photochemical properties in regard to solar energy conersion. In this

experiment they used the method of spray pyrolysis for the synthesis of aluminum doped Fe2(.

'he samples were characteri0ed by using \"ray diffraction techni5ue, scanning electronmicroscopy and impedance analy0er. 'he results showed that the aluminum doped iron oxide

thin film shows the deficiency of oxygen. 'he preparation parameters are controlled so that the

prepared thin film show good 5uality and adhesion with substrate. 'he deposited iron oxide film

showed single hematite phase. 'he crystal structure of nanoparticles was found polycrystalline

rhombohedra and the crystal si0e was 2#"-#nm. Al doped hematite showed better photocurrent as

compared to un"doped hematite. 4y using the spray pyrolysis techni5ue, un"doped and Al doped

Fe2(were deposited on ultrasonically cleaned glass and fluorine doped tin oxide coated glasssubstrate. Fe2(was obtained by adding #.1 9 ferric trichloride in the solution. Al doping was

obtained by adding Aluminum nitrate in the solution. 'his solution was sprayed on the preheated

substrate. 'he temperature of substrate was ept control at 2 @. spray rate was / ccQmin,

no00le diameter #.#/cm and the distance of substrate from no00le was cm.

29


30/79

'amboli et al. %-& reported the synthesis of nanostructure iron oxide thin film by electro"

deposition method.


31/79

)ohande et al. %& reported the synthesis of iron oxide by electro deposition method.

'hey studied the iron oxide nanostructure for their super capacitie application. 'he iron oxide

was deposited electrochemically on a stainless steel substrate. Ferric chloride a5ueous solution of

#.1 9 concentration was used as electrolyte. 'his solution was prepared using double distilled

water. 'he substrate was polished using a fine grade polishing paper, after this the polished

substrate was etched for 1 min in


32/79

stability of the material was checed by heating it for 2hr in air with the temperatures ranging

from -##M= to 12##M=. 'he modified alumina with Fe2( was used for the separation of

hydrocarbons such as alenes and alenes. 'he change in the phases of the material was

measured at the temperatures ranging from -##M= to 12##M=. From results, they found that high

spin FH were present at almost all temperatures in the form of FeAl( but with different

concentrations. 'he material showed completely paramagnetic behaior at -##M=. 4ut at

temperatures higher than -##M= it becomes partially paramagnetic. Aboe -##M= the presence of

iron oxide along with FeH can be seen. Finally Fe2(and FeHwere detected at 12##M=. 'he

parameters showed that regarding to the stability of the material, 6##M= is the most important

temperature.

4huCun et al. %$& reported the synthesis of aluminum doped transition metal ferrite

nanomaterial and study their properties as superconductor electrodes. 'he synthesis of aluminum

doped transition metal ferrite was carried out by using the sol"gel techni5ue. Asymmetric

electrochemical capacitors were formed from nanostructured ferrite compounds and actiated

carbon nanocomposit material. In this paper he synthesis different compounds such as

aluminum" nicel Fe2(-, aluminum"cobalt Fe2(-, aluminum copper Fe2(-. All these compounds

are formed using the sol gel techni5ue. 'he characteri0ation of the materials was done by x"ray

diffraction techni5ue and scanning electron microscopy is used for study of surface morphology.

It was found that metal oxide compounds showed that they possess porous spinel structure. 'heelectrochemical performances of the electrode cells in #.19 @(< was ealuated using cyclic

oltmeter and galanometer. 'he results of the experiments showed that the transition metal

incorporation with the iron oxide enhances the capacitie abilities of super capacitors. 'he pore

si0e of the nanomaterial played an important role in enhancing the capacitie abilities of the

electrodes.

)i et al. %1#& reported the synthesis of nanocrystalline Nicel iron alloy by the electro"

deposition techni5ue. 'his experiment studied the thermal stability and microhardness of thesample material. 'he approximate grain si0e of the alloy was found 1-nm. 'he electrodepostion

was carried out in conentional dis rotating cathode setup. 'he nicel iron alloy was deposited

on annealed =u substrate with /mm diameter. 'he stainless steel was used as woring

electrode. Firstly the copper substrate was glued on this electrode by using siler epoxy. 'hen

32


33/79

substrate polishing was done in phosphoric acid solution, and actiated in 2#


34/79

pulse plating parameters on the electro"deposition of these nanocomposits. Nicel alumina

composites were synthesi0ed using two electrodes configuration i.e. a parallel plate electrode and

impinging Cet electrode. 'he current modulations used in this experiments are direct current,

pulse plating and pulse reerse plating. ;enerally the nanocomposite show more hardness as

compared to pure Nicel coating. 'he enhancement in the hardness was due to Al2(

incorporation. 'he electro"deposition process was carried out by using an acidic nicel

sulphamate electrolyte containing 1.#69 Ni DN


35/79

2.. eferences

1. A. aesano , =.@. 9atsudaa, >.4.9. da =unhab, 9.A.Y. asconcellosb, 4. ooa, 7Influence of potential, deposition

time and annealing temperature on photo electrochemical properties of electrodeposited

iron oxide thin films8. >ournal of Alloys and =ompounds /2#, 22P 23 D2#12E.

/. Alan @leiman"!hwarsctein, 9uhammad N. assim, and *ric ?.

35


36/79

9cFarland.7*lectrodeposited Aluminum"+oped r"Fe2( hotoelectrodesB *xperiment

and 'heory8.=hem. 9ater, 22, /1#P/13, D2#1#E

. 4.>.)ohande, .=.Ambare, !..4haradwaC. 7'hermal optimi0ation and supercapacitie

application of electrodeposited Fe2(thin films8. 9easurement -3, -23P-2, D2#1-E

3. 9. @rifa, 9. 9hadhbi, ). *scoda, >. !aurina, >.>. !u_ol, N. )lorca"Isern, =. Artieda"

;u0m`n, 9. @hitouni. 7hase transformations during mechanical alloying of FeP#

AlP2# =u8. owder 'echnology 2-, 113P12-, D2#1E.

6. 9. !iddi5ue, 9.ia0. 7!tability of modified alumina with Fe2(at high temperatures8.

hysica 4 -#/, 226P22-#, D2#1#E.

$. 4hamini 4huCun, !. Anandan !hanmugam and 9ichelle tan. 7!tudy of aluminium dopedtransition metal ferrite nanomaterials as supercapacitor electrodes8. >ournal of

*ngineering esearch and +esign ol. 2D1E, 1"1#, April, D2#1-E.

1#.


37/79

CHAPTER !

CHARACTERI


38/79

.1. Introduction

'his chapter deals with the techni5ues for experimental inestigation of iron aluminum oxidedeposited nanostructures by electro deposition techni5ue on copper substrate. 'he deposition

potential and deposition time acts as the controlling parameters. !tructural and magnetic

properties of iron aluminum oxide were analy0ed by seeral techni5ues. 'he samples are

characteri0ed by using ibrating sample magnetometer !9, \"ray diffraction and scanning

electron microscopy !*9.

.2. 'ypes of growth

'he growth of synthesi0ed nanostructures can be carried out in two ways which are as underB

1. Te(#late free gro&th

38


39/79

?hen large area growth is re5uired then we normally use template free growth. For template free

growth substrate are re5uired.

2. Te(#late assiste, gro&th

?hen the region of growth is defined, then the template assisted expansion is used for the

synthesis of nanostructure.

?e hae used template free growth for the synthesis of our nanostructures.

.. *xperimental details

'here are many steps inoled for the growth of iron aluminum oxide nanostructures. 'he

essential deposition parameters for the growth of nanostructures are also discussed here. ?e haestarted our wor with the selection of suitable substrate. !ubstrate is often ignored or only

slightly referred although the substrate accompanies thin film from start till end. Ideally a

substrate must proide only the mechanical support and should not interact with the film except

for sufficient adhesion but unfortunately the ideal substrates dont exist. It exerts considerable

influence on the thin film characteristics. %1&

!.!.1 $-strate selection

'he substrate only purpose is to gie mechanical support and in electronic application it usually

seres as an insulator. For long term stability of thin film substrate it should not mae any

chemical reaction with thin film which could change the properties of thin film. 'hus it should

fulfill certain re5uirementsB %2&

G 9echanical strength

G !ufficient adhesion of film to the substrate

G


40/79

G ;lass slides

G olycrystalline ceramics

G !ingle crystal substrates

G 9etal substrates

In our experiment we used copper substrate due to its seeral adantages oer other electrodes.

!ome important features of copper substrate are listed belowB

G It is easily aailable material.

G =opper is strong and easy to shape material.

G It shows good conducting properties without showing much loss of energy.

G +ue to its compatibility with transistori0ed and pulse type power supply, it is

considered to be suitable for metallic electrode material.

!.!.2 $-strate Cleaning

A completely cleaned substrate is a prere5uisite for the preparation of nanostructures. =leaning

techni5ues depend upon the nature of substrate, the type of contaminations, and the degree of

cleanliness re5uired. esidues from manufacturing and pacaging, finger prints, oil and grease

and dust particles are example of fre5uently encountered contaminants %1&. 'he substrate should

be cleaned thoroughly before mounting onto the chamber %&. ?e will do chemical cleaning by

using appropriate solents lie acetone and isopropyl alcohol along with detergent. :ltrasonic

agitation is also applied during chemical cleaning.

!.!.! $-strate etching

40


41/79

First of all copper substrate are etched by acidic solution


42/79

G #.19 FeDN(E.$


43/79

Figure 3.1: setup of 6!ectrodeposition [1)]

!.".1 Annealing

Annealing is a heat treatment which is used for changing the properties of the material such as

strength and hardness. Annealing is used for the remoal of the stresses, refines the structure bymaing it homogeneous, improe the cold woring properties, soften the material and induce

ductility. It is the process which produces the conditions by heating to aboe the re crystalli0ation

temperature, maintain the suitable temperature and then cooling. +iffusion of atoms is occurring

during annealing within the material so the material progress towards its e5uilibrium state.


44/79

1. ecoery of phase which is causes of shifting the material by the remoal of internal stress

and defects.

2. e"crystalline the phase of material where new strain free grains nucleates and grows to

replace the internal stresses.

!.".1.2 Princi#le of annealing

For the annealing process, a large oen is used. 'here is enough large space in the oen so that

the maximum area of our wor pieces is exposed to the heated air. ?e hae annealed our samples

for 1hr at ##M=. (nce the annealing is done, the samples are remaining placed in the oen so

that the oen cools down at normal room temperature. 'he samples are remoed from the oen

after the temperature of oen is resumed to the room temperature.

./ =haracteri0ation 'echni5ues

'he synthesi0ed Iron aluminum oxide was characteri0ed with the following dissimilar

characteri0ation techni5ues in order to explore its different properties i"eR

G \"ray +iffraction D\+E

G !canning *lectron 9icroscopy D!*9E

G ibrating sample magnetometer D!9E

!.%.1 >Ray Diffraction

In 16$/, ?ilhelm =onrad oentgen inestigated some radiation and gie them the name of \"

rays. Initially these rays were unnown naturally but later on, due to further inestigations, it was

found that these are actually electromagnetic radiations with waelength range #.#1"1# . on the

basis of waelength these rays are classified into two types, name as soft x"rays and hard x"rays.

'he x"rays with waelength less than 1 are term as hard x"rays and those haing waelength

longer than 1 are nown as soft x"rays. %6&

1n 1$12, it was concluded by three scientist 9. )aue, @nipping and Friedrich that atomic crystal

and x"ray beam interaction possibly results into different diffraction patterns. In 1$1, x"ray

diffraction phenomenon was firstly used to analy0e the polycrystalline structure of different

samples. %$&

44


45/79

!.%.1.1 Diffraction

'o understand the word diffraction one should be familiar of three phenomenon that are

G !cattering

G Interference

G +iffraction

In scattering, the incident radiations fall on some material and then reemitted into arious

directions. In interference, superposition occurs among different waes of same fre5uency and

conse5uently producing a single oerlapping wae. 'he result of constructie interference

among arious scattered waes from some obCect is termed as diffraction. %1#&

!.%.1.2 Bragg?s :a& an, >Ray Diffraction

\"ray diffraction is the characteri0ation tool which is used to analy0e arious characteristics of a

material, such as identification of different material, crystal defects, lattice constants, preferred

orientation, stresses and geometry of the gien structure. In x"ray diffraction, x"ray beam is the

collimated beam haing waelength range from #.3 to 2 , and the crystalline phases are

responsible factors for its diffraction which is stated by 4raggs lawB

D1E

In the aboe e5uation, d represents the spacing in atomic planes which is the representation of d"

spacing. 'he lambda represents the waelength of incoming x"ray and its alue is 1./- .

whereas n represents any integers with different alues such as n ] #,1,2 .

45


46/79

Figure 3.2 chematic diagram of *ragg7s 8aw [)]

'he intensities related to the diffracted x"rays are inestigated in sense of diffraction angle 2.4raggs relation has two significant ariable factors that are theta DE and lambda DE. 4y

changing any of these two ariables, the conditions of 4raggs law can be achieed %/&. A

schematic diagram of x"ray diffractometer is shown in the fig .. It consists of a sample holder,

+etector and x"ray source. In this procedure x"ray source does not change it position but the

other two components change along their axis.

?hen sample is bombarded with x"rays then the sample as well as detector is in continuous

motion along their axis. It can be analy0ed that the motion of "axis is grater in magnitude twotimes the motion of "axis. 'his is reason we chose angle 2 in place of , in the case of

diffraction patterns. 'he detector collects the data from the diffracted x"rays and gies us the

information.

It is a nondestructie characteri0ation techni5ue. arious positions of peas are analy0ed with

\+ techni5ue, due to which characteri0ation of homogeneous and inhomogeneous strain

becomes easy. 'he si0e of the crystal + is calculated by using the !cherers formula %1#&. 'he

!cherers formula is written asB

46


47/79

Figure 3.3 chematic diagram of 9;a% Diffractrometer [)].

!.%.1.! >RA@ Diffraction yste(

'he \"ray diffractrometer system is an instrument for crystallographic study of resources. In this

method x"rays of nown waelength are worn %&.

It has three maCor partsR

1. \"ay ;enerator

2.;oniometer

!. =ounting and ecording *5uipment.

!.%.1." A,;antages of >RD

G It proides information about the orientation of texture.

G It gies 5uic response to find the unnown material.

G 9inimum sample preparation is re5uired in this approach.

G It is nondestructie techni5ue.

!.%.1.% Uses

47


48/79

It is used for the recognition of single phase resources, multiple phases in microcrystalline

mixtures and amorphous resources. It is also used to decide the phase wor of art of a sample,

unit cell lattice parameters and braais lattice symmetry, residual damage, crystal arrangement

and crystallite si0e and micro strain.

.. !canning electron microscope

'he !*9 is techni5ue to study the surfaces morphology of the material. ?e create image in the

same way as in ' by scanning with an electron beam that generated and focused the samples by

the operation of the microscope. 'he !*9 has high depth of focus as compare with optical

microscope. !o !*9 can generate image haing good representation of + sample. 'he

applications of !*9 imaging encompass microstructural studies, microscopic feature

measurement, fracture and defect studies, thin coating ealuations and surface contamination

assessment etc.

!.3.1. Princi#le of E8

In !*9, we use electrons instead of light to produce image. ?hen heating the metallic filament,

beam of electrons is produced at the top. 'his electron beam follows ertical path through the

column of microscope. 'hen electron beam passes through electromagnetic lenses which focus

and down the beam direct towards the sample. (ther electrons are eCected from the sample whenbeam hits the sample. After collecting the secondary or bacscattered electrons from the detector,

it changes them to a signal that is sent to a iewing screen as compare with our conentional

teleision, thus producing an image.

!.3.2. 4or5ing of E8

At the top there are 7irtual !ource8 presents the electron gun which producing a stream of

monochromatic electrons. 'he stream of electrons is condensed by 1stcondenser lens. 'he mainpurpose of condenser lens is to focus the beam. =ondenser lens wors with the condenser

aperture to eliminate the high"angle electrons from the beam. 'he second condenser lens forms

the thin and coherent beam electrons and controlled by the 7fine loo into current nob8.


49/79

or 7sweep8 the beam in a grid fashion, period of time is determined by the scan speed. 'he final

lens focused scanning beam onto the part of the specimen which is desired. ?hen the beam

strie with sample, and is detected by different Instruments. 4efore the moing of beam, these

instruments count number of interactions and display pixel on a =' whose strength is resolute.

epeated this process until the grid scan is finished. 'he schematic diagram of !*9 is shown in

fig.-.

Figure 3.) chematic Diagram of canning 6!ectron


50/79

Figure 3.+ 6!ectron beam=specimen interactions [12]

50


51/79

!.3." Bac5scattere, electrons BE

?hen electron beam interact with sample atom by elastic collision, it generated a ery high

energy electrons nown as bacscattered electrons because they trael in straight line and moes

ery fast as shown in fig.. 4!* is directly proportional to the atomic number of the sampleelectron. A detector is located in their path in order to form an image with 4!*. After hitting the

detector, a signal is shaped which is used to form the ' image. 4!* also proides topographical

information.

Figure 3.- Different sized nuc!ei of e!ements are shown [13]

!.3.%. econ,ary electrons an, ,etection

!ometimes beam of electrons interact with the electrons present in the atom and sometimes it

interact with nucleus. 'he secondary electrons are shown in fig.3. 'he beam electron does not

attract sample electrons. 'he moement of beam electron is slow due to this interaction as it

repels the specimen electrons. 'he repulsion is so high which cause emission of specimenelectrons from the atom, these are called secondary electrons. ?hen secondary electrons leae

the sample, they moed ery slowly as compare with 4!*.

51


52/79

Figure 3.0 econdar% 6!ectrons [13].

+ue to their slow moement they gets negatie charge so they can attract by positiely chargeddetector. 'his attraction force attracts electrons from large area and especially from corners. 'he

ability of electrons attraction from around corners gies secondary electron image a "

dimensional loo.

!.3.3. HITACHI !"00 N E8

In =entre of *xcellence in !olid !tate hysics :niersity of the unCab, we hae a ery good

resolution !canning *lectron 9icroscope whose model is


53/79

Figure 3.4 >I&(>I 3)55 " 6


54/79

Figure 3./ ?oring of @


55/79

induced electric field, sensed by the picup coils, is proportional to the samples magnetic

moment.

!.'.2 :AE HORE '"00 8

'he !9 used in =entre of *xcellence for !olid !tate hysics is )ae !hore 3-## !9 shown

in fig.1#. It is the most sensitie !9 aailable today haing sensitiity #./Wemu.'he !9 is

calibrated using a sample of nicel with nown magneti0ation before use. 'he nicel sample is

of ery small si0e D/##Wm2E and image charges on larger films are therefore, not effectiely

calibrated. 'he film sample si0e tested in !9 is usually /^1#mm, image charges do influence

such data. Additionally, samples placed with long axis of the film transerse to the field direction

are not entirely within the strongest field and magneti0ation may not fully measure. 'his problem

was reduced by placing samples with their long axes in line with the magnetic field direction.!amples were not cut or patterned to a smaller si0e, in order to allow their processing in to

deices. owders, solids, li5uids, single crystals, and nanostructures are accommodated in the

lae shore !9.

Figure 3.15 8ae hore7s 0)50 @


56/79

.6. efrences

1. ). I. 9aissel, 7.


57/79

CHAPTER NO. "

REU:T AND DICION

57


58/79

-.1 Introduction

'he literature of this chapter proides the brief explanation regarding the results, discussions and

comprehensie conclusion about the material. Nanostructures of iron aluminum oxide were

deposited on the copper substrate using the low cost electrodeposition process. !ix differentsamples had been prepared regarding to the oxidation time. +eposition was done on the copper

substatre for / min, 1# min, 1/ min, 2# min, 2/ min and # mins. )atter on all the six samples

were annealed at ##M= for 1 hr. 'he structural analysis and magnetic properties were

inestigated by using the \"ray diffraction and ibrating sample magnetometer. 'he surface

morphology of the nanostructures was studied by using !canning electron microscopy. 'he main

obCectie of this research wor is to synthesis iron aluminum oxide nanostructures with the help

of simple electrodeposition process. 'heses nanostructures are getting a huge deal of

contemplation due to wide exclusie characteristics and noel applications.

-.2 \"ray +iffraction Analysis for Iron Aluminum (xide

'he \"ray diffraction pattern of Iron aluminum oxide material were obtained by using \"ray

diffractometer and different structural properties of this material such as crystalline si0e, strain

etc. are extracted from these \+ patterns. For this characteri0ation techni5ue, the

diffractometer used in =entre of *xcellence in !olid !tate hysics is 4ruer +6 Adance which

is e5uipped with the =u @L D ] 1./-#/ E radiations.

-. !cherers Formula for =rystalline !i0e +etermination

'he crystalline si0e of all samples was determined from the intense pea in the \+ pattern of

the samples by using simple !cherers formula that is gien belowB

?here

' is the crystalline si0e.

58


59/79

@ is the !cherer constant and its alue is #.$-

4 is Full ?idth at half maximum DF?


60/79

Figure ).1: 9;D patterns for Iron a!uminum oide with ariation in deposition time.

60


61/79

Ta-le ".17

Lattice constant

(a), unit cell

volume (Vcell),

crystalline size (D), X-ray density (dx), and dislocation density () of as-deposited

nanostructures wit varyin! te deposition time"

=rystalline si0e increases with the increase in deposition time from / min to # min. 'he increase

in crystalline si0e with deposition time shows the increases crystalinity of iron aluminum oxide

thin film. =rystalline si0e depends on two factors that are

G Neighboring grain

G !train

ariation in lattice #ara(eters

)attice parameters a for all electrodeposited nanostructures of cubic iron aluminum oxide are

calculated using 4raggs e5uation D*5. -.1E.

a=dhklh2+k2+l2(4.1)

'he trend of lattice parameter ariations with deposition time is shown in Figure -.3. ?ith the

increase in deposition time lattice parameter increases.

61

De#ositio

n ti(e

(in

Latticeconsta

nt()

Unitcell

volume()3

X-raydensity(g cm-3)

Crystallinesize(nm)

Dislocation

density(1x101

m-!)

/ 6.1$$ //1.1 /.121 1/.3 -.#

1/ 6.2# //1.16 /.11$ 2-.3 1.-

# 6.21 //.633 /.1#1 2$ 1.1$


62/79

Figure ).2: ariation in !attice parameters with deposition time

ariation in Dislocation ,ensity

'he dislocation density indicates the amount of defects in a crystal. It is defined as the length ofdislocation lines per unit olume of the crystal. It is calculated by using the e5uation -.2.

= 1

D2 D-.2E

?here, + is crystallite si0e.


63/79

.

Figure ).3: ariation in dis!ocation densit% with deposition time

ariation in crystalline sie

'he aerage crystallite si0e D+E were determined using +ebye !cherrers formula D*5. -.E.

D= 0.9

cos D-.E

?here + is the aerage crystallite si0e of the phase under inestigation, is the waelength of

=u @Lused in \"ray diffraction, j the Full width at half maxima DF?


64/79

with the ariation in deposition time is shown in Figure -.-. 'he crystalline si0e increases with

the increase in deposition time.

Figure ).): ariation of cr%sta!!ine size with deposition time.

ariation in >ray ,ensity

'he \"ray density of nanostructures was estimated using *5. -.-.

=1.66042 A

V(4.4)

?here is unit cell olume and A is atomic weigth of number of atoms or ions in a unit cell %6&.

\"ray density of all the deposited nanostructures is shown in 'able -.1. 'he ariation in x"ray

density with deposition time is shown in Figure -./. 'he trend of x"ray density decreses with theincrease in deposition time.

64


65/79

Figure ).+: ariation in ra% densit% with deposition time.

-.- 9agnetic analysis of as"deposited iron aluminum oxide

Nanostructures

Figure -. shows the room temperature 9"< cure for as"deposited iron aluminum oxide

nanostructures. 'he presence of open hysteresis loop at low field strength indicates

ferromagnetic behaior but at high fields paramagnetic domains indicating that the particles

re5uire further heat treatment.

65


66/79

DaE

DbE

66


67/79

DcE

DdE

67


68/79

DeE

DfE

Figure ).-: cure for sdeposited iron a!uminum oide nanostructures with deposition

time as #a$ + min #b$ 15 min #c$ 1+ min #d$ 25 min #e$ 2+ min #f$ 35 min

68


69/79

-./ 9agnetic analysis of ##M= annealed iron aluminum oxidenanostructures

Figure -.3 shows the 9"< cure for electrodeposited nanostructures after annealing at ##M= in

the presence of magnetic field.

DaE

DbE

69


70/79

DcE

DdE

70


71/79

DeE

DfE

Figure ).0: cures for Iron a!uminum oide nanostructures annea!ed at 355 A( with

deposition time as #a$ + min #b$ 15 min #c$ 1+ min #d$ 25 min #e$ 2+ min #f$ 35 min

71


72/79

-. *ffect of deposition time and annealing on magnetic properties

Figure -.6 shows the coerciity of iron aluminum oxide nanostructures as a function of

deposition time. 'his figure shows how the trend of coerciity changes with the change indeposition time. 'he figure shows that coerciity increases at / and 1# min deposition and then

decreases for 1/ and 2# min depositions. ?e see a further increase for 2/ min deposition.

Figure ).4: ariation in coerciit% with deposition time.

Figure -.$ and -.1# shows the ariations in the magneti0ation and retentiity of iron aluminumoxide nanostructures.

72


73/79

Figure )./:


74/79

-.3 !*9 results of *lectrodeposited samplesB

Fig -.11 shows the !*9 results for iron aluminum oxide nanostructures with / min, 1# min, 1/min, 2# min, 2/ min and # min deposition time.

DaE

74


75/79

DbE

DcE

75


76/79

DdE

DeE

76


77/79

DfE

Figure ).11: 6< images of Iron a!uminum oide "anostructures with deposition time #a$ + min,

#b$ 15 min, #c$ 1+ min, #d$ 25 min, #e$ 2+ min and 35 min.

As we can see from the figure / min deposition shows grain si0e of 1##"12# nm, 1# mindeposition shows 2## nm, 1/ min deposition time shows /# nm, 2# min deposition shows 1-#"16# nm, 2/ min deposition shows grain si0e of 1#"16/ nm and # min deposition showed grainsi0e of 6#"1## nm.

77


78/79

-.6 =onclusions

78


79/79

-.$ eferences

1. @. :sharani, A. . 4alu, ;. !hanmugaal, 9. !uganya and . !. Nagarethinam,International >ournal of !cientific esearch and eiews, 2, /"6, D2#1E.

2. >. 9. Iwata, . . =hopdear, F. ?rong, *. Arehol0 and [. !u0ui, Applied hysics

)etters, 10%, $#/"$11, D2##$E.. 4. +. =ullity, 7*lements of \"ray +iffraction8, Addison"?esley ublishing =ompany,:!A, D1$36E.

New Folderch1

Documents

Transcript of New Folderch1