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  • Title
  • CERTIFICATE
  • ACKNOWLEDGEMENT
  • ABSTRACT
  • DEDICATION
  • Preface
  • CONTENTS
  • List of Figures
  • List of Tables
  • 1. General Introduction
  • 1.1 Introduction to Glaserite
  • 1.1.1 Glaserites structure
  • 1.1.2 Glaserite crystals
  • 1.2 Introduction to Electrical Conductivity
  • 1.2.1 Anisotropic conduction
  • 1.2.2 Hopping conduction
  • 1.3 Dielectrics
  • 1.3.1 Measurement of dielectric tensor
  • 1.3.2 Electric polarisation
  • 1.4 DC Conductivity – Theory and Measurement Techniques
  • 1.4.1 Theory of DC conductivity
  • 1.4.2 DC conductivity measurement methods
  • 1.4.3 General methods of measurement
  • 1.4.4 Ohmmeter and voltmeter–ammeter measurements
  • 1.4.5 Potential probe method
  • 1.4.6 Spreading resistance method
  • 1.4.7 Four point probe methods
  • 1.4.8 Electrometer methods
  • 1.5 Introduction to AC Conductivity
  • 1.5.1 General theory
  • 1.5.2 AC electrical response of ionic conductors
  • 1.6 Theory of Dielectrics and Dielectric Spectra Analysis
  • 1.6.1 Dielectric materials
  • 1.6.2 Behavior of dielectrics in time varying field
  • 1.6.3 Complex plane analysis
  • 1.6.4 Equivalent circuit analysis
  • 1.6.5 Theoretical aspect of Cole - Cole plot
  • 1.6.6 Dielectric relaxation
  • 1.6.7 Static and optic dielectric constant
  • 1.6.8 Temperature dependence of the relaxation time
  • 1.6.9 Interpretation of the dielectric behaviour
  • 1.7 Electrode Effects on the Measurement of Dielectric Properties
  • 1.8 Dielectric Spectroscopy–Outlook
  • 1.9 Introduction to Ferroelasticity
  • 1.9.1 Ferroelastic materials
  • 1.9.2 Ferroelastic crystals
  • 1.9.3 Ferroelastic phase transition
  • 1.9.4 Order of phase transition
  • 1.9.5 Landau theory of phase transition
  • References
  • 2. Experimental Technique
  • 2.1 Introduction
  • 2.2 Conductivity Measurement Methods
  • 2.2.1 DC electrical conductivity measurement
  • 2.2.2 Alternating current bridge method
  • 2.3 The Conductivity Cell
  • 2.4 DC Conductivity Measurements
  • 2.5 AC Conductivity Measurements
  • 2.5.1 Conducting an impedance spectroscopy (IS) experiment
  • Fig. 2.8: DC conductivity measurement setup.
  • Fig.2.9: Close up view of keithley electrometer.
  • Fig.2.10: AC conductivity and dielectric measurement setup.
  • Fig.2.11: Close up view of LCR meter.
  • 2.6 Sample Preparation
  • 2.6.1 Crystal growth from solution
  • 2.7 Constant Temperature Bath
  • Fig.2.12: A view of the constant temperature bath.
  • Fig. 2.13: Photograph of the crystal growth setup.
  • 2.8 Digitally Programmable Temperature Controller
  • Fig.2.14: Photograph of the digitally programmable temperature controller.
  • 2.9 Identification of the Faces Using Stereographic Projection
  • Fig.2.15: Photograph of the crystal cutter.
  • Fig.2.16: Close up view of the goniometer in the crystal cutter.
  • 2.10 Crystal Cutting and Polishing
  • Fig.2.17: Photograph of the crystal polishing unit.
  • References
  • 3. Electrical Conductivity and Dielectric Studies ofTripotassium Sodium Disulphate Single Crystal
  • 3.1 Literature Review
  • 3.2 Experimental Technique
  • 3.2.1 Sample preparation
  • Fig.3.1: Photograph of the grown K3Na (SO4) 2 Crystals.
  • Fig.3.2: Morphology of the K3Na (SO4) 2 crystal.
  • 3.2.2 Density measurement
  • 3.2.3 Powder X-ray diffraction of K3Na (SO4) 2
  • 3.2.4 Cutting and polishing
  • Fig.3.4: Stereographic projection of K3Na (SO4) 2 Crystal projected at 100direction.
  • Fig.3.5: Stereographic projection of K3Na (SO4) 2 crystal projected at 001direction.
  • Fig.3.6: Solubility curve of K3Na (SO4)
  • 3.3 Measurements of DC Electrical Conductivity
  • 3.3.1 DC Conductivity along a-axis
  • Fig.3.7: Variation of dc conductivity with temperature along a-axis intemperature region 303 K-430 K.
  • 3.3.2 DC Conductivity along c-axis
  • Fig.3.8: Variation of dc conductivity with temperature alongc-axis in the temperature range 303 K-430 K.
  • 3.3.3 Activation energy along a and c axes
  • Table 3.3: Activation energies along a and c axes.
  • Fig.3.9: Temperature dependence of dc conductivity of K3Na (SO4) 2single crystal in different orientations.
  • 3.4 Measurements of AC Electrical Conductivity
  • 3.4.1 Complex impedance analysis
  • Along a-axis
  • Fig.3.10: Cole-Cole plots of K3Na (SO4) 2 along a-axis for differenttemperature.
  • Along c-axis
  • Fig.3.11: Cole-Cole plots of K3Na (SO4) 2 along c-axis for differenttemperatures.
  • 3.4.2 Dielectric analysis
  • Frequency dependent dielectric spectra
  • Temperature dependent dielectric spectra
  • 3.4.3 Conductivity analysis
  • Frequency dependent conductivity spectra
  • Temperature dependent conductivity spectra
  • 3.5 Discussion
  • Fig.3.28: Thermogravimetric graph (TGA) for the grown sample of K3Na (SO4) 2.
  • Fig.3.29: Differential scanning thermograph (DSC) taken for the grownsample of K3Na (SO4) 2.
  • 3.6 Conclusion
  • References
  • 4. Electrical Conductivity and Dielectric Studies ofTripotassium Sodium Dichromate Single Crystal
  • 4.1 Literature Review
  • 4.2 Experimental Technique
  • 4.2.1 Sample Preparation
  • Fig.4.3: Photograph of the grown K3Na (CrO4) 2 crystal.
  • Fig. 4.4: Morphology of K3Na (CrO4) 2 Crystal.
  • 4.2.2 Density measurement
  • 4.2.3 Powder X-ray Diffraction of K3Na (CrO4) 2
  • Fig.4.7: Stereographic projection of K3Na (CrO4) 2 crystal projected at 100direction.
  • Fig.4.8: Stereographic projection of K3Na (CrO4) 2 crystal projected at 001direction.
  • 4.3 Measurements of DC Conductivity
  • 4.3.1 DC conductivity along a-axis
  • 4.3.2 DC conductivity along c-axis
  • 4.3.3 Activation energy along a and c axes
  • 4.4 Measurements of AC Electrical Conductivity
  • 4.4.1 Complex impedance analysis
  • Along a-axis
  • Along c-axis
  • 4.4.2 Dielectric Analysis
  • Frequency dependent dielectric spectra
  • Temperature dependent dielectric spectra
  • 4.4.3 Conductivity Analysis
  • Frequency dependent conductivity spectra
  • Temperature dependent conductivity spectra
  • 4.5 Discussion
  • 4.6 Conclusion
  • References
  • 5. Electrical conductivity and Dielectric Studies ofTripotassium sodium diselinate Single Crystal
  • 5.1 Literature Review
  • 5.2 Experimental Technique
  • 5.2.1 Sample Preparation
  • Fig.5.3: Photograph of the grown K3Na (SeO4) 2 crystal.
  • Fig.5.4: Morphology of K3Na (SeO4) 2 Crystal.
  • 5.2.2 Density measurement
  • 5.2.3 Powder X-ray Diffraction of K3Na (SeO4) 2
  • Fig.5.7: Stereographic projection of K3Na (SeO4) 2 crystal projected at100 direction.
  • Fig.5.8: Stereographic projection of K3Na (SeO4) 2 crystal projected at010 direction.
  • Fig.5.9: Stereographic projection of K3Na (SeO4) 2 crystal projected at001 direction.
  • 5.3 Measurements of DC Conductivity
  • 5.3.1 DC Conductivity along a-axis
  • 5.3.2 DC conductivity along b-axis
  • 5.3.3 DC conductivity along c-axis
  • 5.3.4 Activation energy along a, b and c axes
  • 5.4 Measurements of AC Electrical Conductivity
  • 5.4.1 Complex impedance analysis
  • Along a-axis
  • Along b-axis
  • Along c-axis
  • 5.4.2 Dielectric analysis
  • Frequency dependent dielectric spectra
  • Temperature dependent dielectric spectra
  • 5.4.3 Conductivity analysis
  • Frequency dependent conductivity spectra
  • Temperature dependent conductivity spectra
  • 5.5 Discussion
  • 5.6 Conclusion
  • References
  • 6. Conclusions and Future Work
  • 6.1 Conclusions
  • 6.1.1 Tripotassium sodium disulphate (K3Na (SO4) 2 or KNS)
  • 6.1.2 Tripotassium sodium dichromate (K3Na (CrO4) 2 or KNCr)
  • 6.1.3 Tripotassium sodium diselinate (K3Na (SeO4) 2 or KNSe)
  • 6.2 Directions of Future Work