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TITLE
CERTIFICATE-1
CERTIFICATE-2
DECLARATION
ACKNOWLEDGEMENT
PREFACE
PUBLICATIONS / PRESENTATIONS IN SEMINARS /CONFERENCES /JOURNALS
ABSTRACT
CONTENTS
LIST OF FIGURES
LIST OF TABLES
1. THEORIES AND TECHNIQUES OF CRYSTAL GROWTH
1.1 Introduction
1.2 Thermodynamics of crystal growth
1.3 Nucleation
1.4 Theories of crystal growth
1.4.1 Surface Energy Theory
1.4.2 Diffusion Theories
1.4.3 The Surface Nucleation Models
1.4.4 Screw Dislocation Theory
1.5 Crystal growth techniques
1.5.1 Growth from Solid
1.5.2 Growth from Solution
1.5.3 Growth from Vapour
1.5.4 Melt Growth Techniques
1.6 References
2. GEL METHOD AND RARE EARTH OXALATE CRYSTALS
2.1 Introduction
2.2 The structure and properties of gel
2.3 Preparation of hydro silica gel
2.4 Gelation mechanisms and gel structure
2.5. Crystallization in gel medium
2.6 Nucleation control in gel
2.7 Nature of the gel grown crystals
2.8 Rare earth oxalate crystals
2.9 Advantages of gel technique
2.10 References
3. CHARACTERIZATION TECHNIQUES
3.1 Introduction
3.2 X-Ray Diffractometry
Fig 3.1: Bruker AXS D8 Advance X-ray Diffractometer
3.3 Fourier transform infra red spectroscopy
3.4 Thermal Analysis – TG/DTA
3.5 Thermal Analysis –DSC
3.6 Elemental analysis using inductively coupledplasma atomic emission spectrometer (ICP –AES)
3.7 Microhardness measurements
3.8 Electrical conductivity measurements usingimpedance analyzer
Fig. 3.6. HP4192A Impedance Analyzer
3.9 Photoconductivity
3.10 Microwave dielectric studies
3.11 Energy dispersive analysis by x-rays (EDAX)
3.12 Reference
4. GROWTH STUDIES
4.1 Introduction
4.2 Chemistry associated with growth of rare earth oxalate crystals
4.3 Hydro silica gel as growth medium
4.4 Preparation of hydro silica gel
4.5 Preparation of supernatant solution
4.6 Growth of rare earth oxalate crystals
Fig.4.3 Yttrium Oxalate tetragonal crystals heaped on a glass plate in redbackground (left) Crystallization of the Yttrium Oxalate crystalsin the dissolution area – magnified (right) .
Fig. 4.4 A well faceted Yttrium Oxalate crystal (x20)
Fig. 4.5 An enlarged Yttrium Oxalate crystal with its growth layers (x50)
Fig.4.6 Microscopic view of Yttrium Oxalate crystals (*20 magnification) Single, multi nucleated, branched, additional growth can beobserved.
4.7 Growth kinetics
Fig. 4.7 Growth system of Yttrium mixed Oxalate crystals
Fig. 4.8 Growth system of NdBaCuOx, PrBaCuOx, GdBaCuOx crystals
4.8 Conclusion
4.9 References
5. SPECTROSCOPIC AND THERMAL CHARACTERIZATION
5.1. Introduction
5.2. X-ray Analysis
5.3 Analysis Infrared
5.4 Analysis Using Inductively Coupled Plasma Atomic EmissionSpectrometer (ICP –AES)
5.5 Energy dispersive X-ray analysis
5.6 THERMAL ANALYSIS
5.7 Differential scanning calorimetry (DSC)
5.8 Conclusion
5.9 References
6. MICROHARDNESS
6.1 Introduction
6.2 Vickers hardness test method
6.3 Microhardness measurements of the pure and mixed rare earth oxalate crystals
6.4 Discussion on microhardness studies
6.5 Conclusion
6.6 Reference
7. ELECTRICAL AND OPTICAL PROPERTIES OF RARE EARTH MIXED OXALATE CRYSTALS
7.1 Introduction
7.2 Frequency dependence on dielectric constant and dielectric loss rare
7.3 Frequency and Temperature Dependence of Conductivity
7.4 Activation energy of Rare Earth Oxalate Crystals
7.5 Photoconductivity
7.6. Conclusion
7.7. References
8. MICROWAVE DIELECTRIC STUDIES ON RARE EARTH MIXED OXALATE CRYSTALS
8.1 Introduction
8.2. Microwave experimental set up