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
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