Girls College for Arts Science and Education

Ain Shams University

Some Physical Properties of Zinc Cobalt Aluminum Ferrite

Doped by Rare Earth Elements and its

Nanocomposites with Polymer

Presented By

Nawara Mohamed Saleh

Thesis Submitted to Physics Department

Girls College for Arts, Science and Education, Ain Shams

University

For partial fulfillment The Degree of Master in Science

(Solid State Physics)

Under Supervision

Prof. Dr. D.Sc. Mohamed Ali Ahmed Professor of Experimental Physics, Physics Department, Faculty of Science, Cairo

University.

Prof. Dr. Samiha Tadros Bishay Professor. of Solid State Physics, Girls College for Arts, Science and Education, Ain Shams

University.

Assoc. Prof. Dr. Rasha Khafagy

Associate Professor of Physics, Girls College for Arts, Science and Education, Ain Shams

University.

(2012)

Girls College for Arts Science and Education

Ain Shams University

Approval Sheet

Thesis for the partial fulfillment of

Degree of Master of Science (Solid State Physics)

Presented by

Nawara Mohamed Saleh Title of the thesis

“Some Physical Properties of Zinc Cobalt Aluminum

Ferrite Doped by Rare Earth Elements and its

Nanocomposites with Polymer”

Thesis Supervisors Signature

Prof. Dr. D.Sc. Mohamed Ali Ahmed ……………… Professor of Experimental Physics Department,

Faculty of Science, Cairo University.

Prof. Dr. Samiha Tadros Bishay…………………….. Professor of Solid State Physics,

Girls College for Arts, Science and Education,

Ain Shams University.

Dr. Rasha Khafagy …………………………. Associate Prof Physics

Girls College for Arts, Science and Education,

Ain Shams University.

Post graduate administration Date of research: / / 2012 Date of Approval: / / 2012

Approval Stamp:

Approval of Faculty Council: / / 2012

Approval of University Council: / / 2012

Girls College for Arts Science and Education

Ain Shams University

Student name: Nawara Mohamed Saleh

Scientific degree: Bachelor of Science (Physics)

Department: Physics Department.

Faculty: University College of El-Gabale El-Ghaarbi, Science Gherian, Libya.

University: El-Gabale El-Ghaarbi

Date of graduation: 2004

كلت الباث

داب والعلوم والخزبتللآ

قسن الطبعت

ت للاو سك كوبلج الوهوم فزاج الوطعن بالعاصز الادرة ائبعض الخواص الفش

وهخزاكباحه هع البولوز

قذخ اىجبحثخ

وارة هحوذ صالح

اىعي اىبخغزش فىيحظه عي دسخخ

ف عي اىفضبء( )رخظض اىداذ

رحذ إششاف

محمد علي احمد/ا.د

خبعخ اىقبشح -اىعي ميخ -قغ اىفضبء -اىفضبء اىزدشجخ عي اىاد أعزبر

سميحة تادرس بشاى /ا.د

ع شظخبعخ -ىجبدا ميخ -قغ اىفضبء -عي اىاد أعزبر

رشا محمود خفاجي /د

ع شظخبعخ -ىجبدا ميخ -ثقغ اىفضبء غبعذ أعزبر

(2012)

ACKNOWLEDGMENT

First of all, thanks to Allah for giving me hope and strength to finish this

work.

I would like to thank Professor Mohamed Ali Ahmed, Professor of

material science, for suggesting the point of research, giving me the

opportunity to work with him and join his research group at the Materials

Science Lab. (1), his oversight, insightful guidance, persistent support,

enthusiastic encouragement throughout the thesis work, and giving me the

opportunity to see my own ideas through to fruition.

I would like to express my respect and gratitude, to Professor Samiha

Tadros Bishay, Professor of Solid State Physics, Girls College for Arts,

Science and Education, Ain Shams University. For doing her best and a very

big effort from the moment of the beginning to the end of my master work in

proposing, planning the investigation, continuous interest, and for her moral

treatment.

Also, I would like to express my deep gratitude to Associate Prof. Dr.

Rasha Khafagy, Associate Prof of Physics, Girls College for Arts, Science

and Education, Ain Shams University. For her sincere supervision, invaluable

guidance through this work and fruitful discussion, guiding me any time I

need and continuous encouragement.

Many thanks for all members of Materials Science Lab. (1) for their

help in the progress of this work.

Special tanks to my husband Naji for his support during this work and

my sons Sundes and Abdalwahed.

I

CONTENTS:

CHPTER ONE: INTRODUCTION

1.A: Literature Survey 3

1.B: Theoretical Background 17

1.B.1: Electrical properties 17

1.B.1.1: Conductivity in ferrite materials 17

1.B.1.2: Conduction mechanisms in ferrites 18

1.B.1.2.a: Tunneling model 19

1.B.1.2.b: Hopping model 21

1.B.1. 2.c: Polarons in molecular crystals 21

1.B.1. 2.d: Verwey model 22

1.B.1.3: Different types of polarization 23

1.B.1.3.a: Electronic polarization 23

1.B.1.3.b: Orientaional polarization 24

1.B.1.3.c: Ionic polarization 25

1.B.1.3.d: Interfacial polarization 26

1.B.1.4: The frequency dependence of dielectric constant and

dielectric loss

27

1.B.1.5: Temperature dependence of dielectric constant and dielectric

loss

30

1.B.2: Magnetic properties 33

1.B.2.1: Types of magnetic materials 33

1.B.2.1.a: Diamagnetic materials 33

1.B.2.1.b: Paramagnetic materials 33

1.B.2.1.c: Ferromagnetic materials 34

1.B.2.1.d: Ferrimagnetic materials 34

1.B.2.1.e: Antiferromagnetic materials 35

1.B.2.1.f: Superparamagnetic materials 35

CHPTER TWO: CRYSTAL STRUCTURE

2.1: Introduction 37

2.2: Chemical composition of ferrites 37

II

2.3: The spinel structure 38

2.3.1: Normal spinel 39

2.3.2: Inverse spinel 40

2.3.3: Mixed spinel 41

2.4: Classes of crystal structure in ferrite 41

2.5: Ionic charge balance and crystal structure 42

2.6: Distribution of metal ions over the tetrahedral and octahedral sites 44

2.7: Some factors influence the distribution of metal ions over the

tetrahedral and octahedral sites

46

2.7. a: Site preferences of the ions 46

2.7.b: The electronic configuration 48

2.7.c: The electrostatic energy 48

2.7.d: The oxygen parameter (u) 49

2.8: Unit cell dimensions 50

2.9: Polymeric structure 53

CHAPTER THREE: APPLICATIONS OF FERRITE

3.1: Introduction 55

3.2: Ferrite isolators 55

3.3: Ferrites as nonlinear circuit element 56

3.4: Ferrite cores 57

3.5: Ferrite core memory 59

3.6: Piezo magnetic ferrites 59

3.7: Ferrites in relays 61

3.8: Ferrites for recording Head 62

3.9: EMI filter 62

3.10: Radar-absorbent material 63

3.11: Ferrites in tumor therapy 64

3.12: Magnetic drug delivary 65

CHAPTER FOURE: EXPERIMENTAL TECHNIQUES

4.1: Sample Preparation 67

4.1.1: Preparation of the first group by flash autocombustion method 67

4.1.2: Preparation of the second group 68

III

4.1.3: Preparation of polymer/ferrite cor-shell nanocomposites 69

4.2: Sample analysis 70

4.2.1: X-Ray analysis 70

4.2.2: Transmission electron microscope analysis 71

4.2.3: FTIR analysis 71

4.3: Electrical properties measurements 71

4.3.1: Dielectric constant measurements 71

4.3.2: Electrical resistivity measurements 73

4.3.3: Thermoelectric power 74

4.4: Magnetic properties 75

4.4.1: Methods of measuring magnetic susceptibility 75

4.4.1.1: Gouy’s method (the homogeneous field method) 76

4.4.1.2: Faraday’s method (the non-homogeneous field method) 77

CHAPTER FIVE: RESULTS AND DISCUSSION

5.A: Group One: Effect of Zn-Content on the Physical Properties of

ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤ 0.6

83

5.A.1: Effect of annealing temperature on the crystallization of the samples. 83

5.A.2: X-ray diffraction analysis for the samples ZnxCo1-xAl0.5Fe1.46La0.04O4;

0.0≤x≤0.6 annealed at 700oC

85

5.A.3: FTIR analysis 89

5.A.4: Particle morphology by HRTEM 94

5.A.5: Dielectric constant measurements 96

5. A.5.1: Effect of temperature and frequency on the real part of dielectric

constant (')

96

5.A.5.2: Effect of temperature and frequency on the imaginary dielectric

constant (")

100

5.A.5.3: Effect of temperature and frequency on the ac conductivity 104

5.A.5.4: Effect of Zn-content on the ac conductivity 104

5.A.5.5: Calculation of activation energy at different temperatures regions 106

5.A.5.6: Measurement of dielectric parameters in isothermal conditions 109

5.A.5.7: Determination of the relaxation time using the Cole-Cole diagram

method

111

5.A.5.8: Seebeck coefficient measurements 114

5.A.6: Magnetic measurements 117

5.A.6.1: Measurement of magnetic susceptibility at different temperatures 117

5.A.6.2: Evaluations of some magnetic parameters 121

IV

5. B: Group Two: Effect of Rare Earth Doping on the Physical Properties of

Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La, Ce, Pr and Sm

126

5. B-1: Phase formation of rare-earth doped ferrites 128

5. B.1. 1: Dependence of lattice parameter (a) on the ionic radii of the

rare earth elements

132

5. B-2: Effect of rare earth doping on the crystallites size and microstructure of

rare-earth doped ferrites (XRD versus HRTEM)

135

5. B-3: Dielectric measurements 138

5. B-3-1: Effect of temperature and frequency on the dielectric constant and

dielectric loss of different rear earth doped ferrites

138

5. B-3-2: Effect of temperature and frequency on the ac conductivity of rare

earth doped ferrites

142

5. B-4: Magnetic measurements 145

5. C: Group Three: Study of Polymer/Ferrite Core-Shell Nanocomposite 150

5. C.1: Effect of polymer type on the core-shell nanocomposite 150

5. C.1.1: XRD study for core-shell nanocomposites 152

5. C.1.1.1: X-ray diffraction of pure polymers 152

5. C.1.1.2:X-ray diffraction of core-shell nanocomposites 158

5. C.1.2: High resolution transmission electron microscopy (HRTEM) 162

5. C.1.3: Dielectric measurements of polymer/ferrite core-shell

nanocomposites

168

5. C.1.4.1: ac conductivity of core shell nanocomposites at room temperature 170

5. C.1.4. 2: Temperature dependence of ac conductivity of the core-shell

nanocomposites

171

5. C.1.5: Magnetic measurements for core-shell nanocomposites 176

5. C.2: Effect of PVP Ratio 178

5. C.2.1: ac conductivity of PVP/ Zn0.5Co0.5Al0.5Fe1.46La0.04O4 core-shell

nanocomposites

178

5. C.2.2: Magnetic measurements of PVP/Zn0.5Co0.5Al0.5Fe1.46La0.04O4 core-

shell nanocomposites with different PVP ratios

180

CHAPTER SIX: SOME APPLICATIONS OF THE INVESTIGATED

SAMPLES

6. A: Methodology of applications 183

6. B: Results and dissections 184

6. B. 1: Effect of zinc concentration on the purification and de-inking of water

184

V

6. B. 2: Effect of rare earth element on the purification and de-inking of water 185

6. B. 3: Effect of polymer type of core-shell nanocomposite on the purification

and de-inking of water

186

VI

LIST OF TABLES:

Table (2-1): The radii of tetrahedral and octahedral sites in some ferrites 47

Table (2-2): Ionic radii of some divalent and trivalent metal ions 47

Table (2-3): The unit cell parameters of some ferrites 50

Table (2-4): The structure of the different polymers 54

Table (5-1): Effect of Zinc concentration on the IR band positions.. 91

Table (5-2): FTIR band assignments for ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6. 91

Table (5-3): Activation energy in ferri-magnetic (E1(eV)) and paramagnetic

(E2(eV)) regions for ZnxCo1-xAl0.5Fe1.46La.04O4; 0.0≤x≤0.6.

107

Table (5-4): The relaxation time for ZnxCo1-xAl0.5Fe1.46La.04O4; (x=0.0,

0.2, 0.3, 0.5)

112

Table (5-5): The temperature of highest Seebeck coefficient (TS), the charge

carrier concentration (n) and the ac conductivity at 550K for

ZnxCo1-xAl0.5Fe1.46La.04O4; 0.0≤x≤0.6.

116

Table (5-6): Curie temperature TC (K), and effective magnetic moment

eff (BM)

122

Table (5-7): Rare earth ionic radius and the lattice parameter for

Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La, Ce, Pr and Sm

132

Table (5-8): A comparison between the data calculated from HRTEM and

XRD

136

Table (6-1): Comparison results for the color index analysis data 187

VII

LIST OF FIGURES:

Fig. (1-1): Schematic diagrams illustratine the electron hopping and the

electron tunneling in the two case a square and a triangular potential barrie

20

Fig. (1-2): The electronic polarization, the electron cloud is displaced due to

applied external electric field

23

Fig. (1-3): The orientational polarization, the already exsit dipoles are

aligned in the direction of the external field

25

Fig. (1-4): The relative displacement of the anion and cation charge centers 25

Fig. (1-5): Relaxation spectrum of a two layer dielectric 27 Fig. (1-6): Dispersion in resistivity and dielectric constant for nickel- Zinc

ferrite

28

Fig. (1-7): Capacitor with double layer dielectric 28 Fig. (1-8): Frequency dependence of the real and imaginary parts of the

dielectric constant

29

Fig. (1-9): Variation of' with temperature at different frequencies for KBr 31

Fig. (1-10): Variation of (a)' and (b) tan with temperature at different

frequencies for a crystal with conduction loss (NaIO4)

32

Fig. (1-11:a-d): The temperature dependence of the reciprocal magnetic

susceptibility: (a) Curie law behavior of a paramagnetic solid. (b) Curie-

Weiss law behavior of a ferromagnetic solid above the Curi temperature in

the paramagnetic state. (c) Curi- Weiss law behavior of an antiferromagnetic

solid. (d) Behavior of a ferromagnetic solid

36

Fig. (2-1):Filling a plane with spheres (single and two layer) 42 Fig. (2-2): Tetrahedral (A) site and octahedral (B) site 44

Fig. ( 2-3):Unit cell for spinel structure with alternating tetrahedral (AO4)

and octahedral (BO6) coordinated units (four each per unit cell)

51

Fig. (2-4): Nearest neighbours of (a) a tetrahedral site, (b) an octahedral

site and(c) an anion site

52

VIII

Fig. (3-1): Ferrite microwave Isolator 56 Fig. (3-2): Mn-Zn Ferrite in the form of torroid core used as non-linear

electronic circuit component 57

Fig. (3-3): Different types of ferrite cores, and schematic diagram of memory

core based on square loop ferrite

58

Fig. (3-4): Ferrite core memory 59

Fig. (3-6) :Ferrites used in Relays 61

Fig. (3-7): Hard Disk Sector, that showes the magnetic recording head made

of ferrite

62

Fig. (3-8): Ferrites as electromagneti wave filter. 63

Fig. (3-9): Radar absorping material 64

Fig. (3-10) Ferrite in tumor therapy 65

Fig. (3-11) Magnetic drug delivary 65

Fig. (4-1): Photograph of the flame produced in the preparation of the

samples

68

Fig. (4-2): The Bridge used for measuring the ac dielectric constant, model

HIOKI 3532, RLC meter

73

Fig. (4-3): The thermoelectric power measurements system I Spring, A-B

Cupper plate heater with thermocouple, E- F Sample Holder, C- D Sample

Space H and G Electrodes for connecting

75

Fig. (4-4): (a) Schematic diagram of Faraday’s method for measuring

magnetic susceptibility. (b) Specimen in non-homogeneous field

79

Fig. (5-1): The scheme of the experimental work 81

Fig. (5-2): The effect of annealing temperature on the crystallite of

Zn0.1Co0.9Al0.5Fe1.46La0.04O4

84

Fig. (5-3): XRD patterns for the samples ZnxCo1-xAl0.5Fe1.46La0.04O4;

0.0≤x≤0.6

Fig. (5-4: a, b): XRD calculated parameters for

ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6: (a) Lattice parameter, (b) Crystal size

as calculated from XRD data.

86 88

Fig. (5-5): Infrared spectra of ZnxCo1-xAl0.5Fe1.46La.04O4; 0.0≤x≤0.6. 90

IX

Fig. (5-6): The dependence of the two absorption bands position on Zn-

content

92

Fig. (5-7: a-e): TEM micrograph for the samples

ZnxCo1-xAl0.5Fe1.46La.04O4; x= 0.0, 0.1, 0.2, 0.4 and 0.5

95

Fig. (5-8: a-g) :Dependence of ' on absolute temperature at different

frequencies for the sample ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6

97

Fig. (5-9: a-g) : Relation between " and absolute temperature as a function

of frequency for the samples: ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6

101

Fig. (5-10: a, b) The factors affecting on the ac conductivity : (a)

temperature dependence of as a function of frequency 1kHz ≤f≤100kHz for

the sample with x= 0.2, (b) vs absolute temperature for all the samples at

1kHz and the inset for the dependence of on Zn-content at 1kHz and 550K.

105

Fig. (5-11: a-g): Varation of ac conductivity Ln with the resoprical of the

absolute temperature (1000/T) for the sample

ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6

107

Fig. (5-12:a-c) The relation between ln and ln for the samples

ZnxCo1-xAl0.5Fe1.46La0.04O4; x=0.2, 0.3, 0.5 at different temperatures

110

Fig. (5-13) The dependence of the exponent frequency s on the frequency at

324K for the samples ZnxCo1-xAl0.5Fe1.46La0.04O4 x= 0.0, 0.2, 0.3 and 0.5

111

Fig. (5-14: a-d). The relation between ' and " for the sample

ZnxCo1-xAl0.5Fe1.46La0.04O4:: x=0.0, 0.2, 0.3, 0.5 at 420K

113

Fig. (5-15:a-g) :Dependence of Seebeck voltage cofficient on the average of

absolute temperature for the sample

ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6

115

Fig. (5-16:a-g) Dependence of the molar magnetic susceptibility (M) on the

absolute temperature for the sample ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6 at

different magnetic field intensities

118

Fig. (5-17:a-g) Dependence the reciprocal of the molar magnetic

susceptibility (M-1

) on the absolute temperature T(K) for the samples

ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6. at different magnetic field intensities

123

X

Fig. (5-18): Dependence of Zn-content on the effective magnetic moment for

the samples ZnxCo1-xAl0.5Fe1.46La0.04O4; 0.0≤x≤0.6

125

Fig. (5-19): XRD patterns for the samples

Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La, Sm, Pr, Ce 129

Fig. (5-20: a- d) Computerized fitted XRD spectra 130 Fig. (5-21). The lattice parameter according to dopping with different rare

earth ionic radii elements

133

Fig. (5- 22): TEM micrograph for the samples

ZnxCo1-xAl0.5Fe1.46R0.04O4;R=La, Ce, Pr, Sm

135

Fig. (5-23). The particle size calculated from HRTEM 136

Fig. (5-24: a-d) : Relation between ' and absolute temperature as a function

of frequency for the sample Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La, Sm, Pr, Ce

138

Fig. (5-25:a-d) : Relation between " and absolute temperature as a function

of frequency for the samples Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La, Sm, Pr, Ce

141

Fig. (5-26): Variation of ac conductivity with the absolute temperature for

Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R= Sm, Pr, Ce, La

143

Fig. (5-27: a-c); The effect of the rare earth ionic raduis of

Zn0.5Co0.5Al0.5Fe1.46R0.04O4: R= Sm, Pr, Ce, La on the: (a) ac conductivity at

room temperature. (b) ac conductivity at600K. (c) the obtained transition

temperature of

144

Fig. (5-28:a-d) Dependence of the molar magnetic susceptibility (M)

on the absolute temperature for the samples Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La,

Sm, Pr, Ce.at different magnetic field intensities

146

Fig. (5-29: a-d): Dependence the reciprocal of the molar magnetic

susceptibility (M-1

)on the absolute temperature for the sample

Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R=La, Sm, Pr, Ce. at different magnetic field

intensities

147

Fig. (5-30: a, b): The variation of the Curie temperature (Tc) and effective

magnetic moment eff)with the ionic radii of the rare earth elements-doped

ferrite: Zn0.5Co0.5Al0.5Fe1.46R0.04O4; R= Sm, Pr, Ce and La

149