|
| |||||||||||
| |||||||||||
Full Screen- TITLE
- CERTIFICATE-1
- CERTIFICATE-2
- DECLARATION
- ACKNOWLEDGEMENT
- CONTENTS
- PREFACE
- LIST OF PUBLICATIONS
- LIST OF PATENTS
- I. Introduction
- I.1 Superconductivity
- I.2 Properties of Superconductors
- I.3 High Temperature Superconductors
- I.3.1 Y-Ba-Cu-O. System
- Table 1.1 List of major high temperature superconductors
- Fig. I.I Geometrical diagram representing the crystal structure of (A) Orthorhombic (B) Tetragonal phases of YBa2Cu3O7
- Fig.I.2 X-ray diffraction patterns of YBa2Cu3O7-8 (A) OrthorhombicB) Tetragonal phases
- Table 1.2 X-ray diffraction data of YBa2Cu3Ox,
- Fig. 1.3 Variation of critical temperature (TC) with oxygen stoichiometry x (=7-6) in YBa2Cu3O7-8
- I.3.2 Bi-Sr-Ca-Cu-O System
- Fig 1.4 Compatibility regions in the pseudoternary Y2O3-BaO-CuO systemas determined at 950°C
- I.3.3 Tl-Ba-Ca-Cu-O System
- I.3.4 Hg-Ba-Cu-O System
- I.4 Effect of Oxidic Additions and Substitutions in YBa2Cu3O7-8
- I.5 YBa2Cu3O7-8 Thick films
- I.6 Substrates for YBa2Cu3O7-8 Films
- Table 1.4 Physical properties of substrates used for YBCO films
- References
- II. Experimental Methods
- II.1 Processing of YBa2Cu3O7-8 Superconductors
- II.2 Processing of REBa2HfO5.5 [RE= Y, Gd, Sm] Ceramic Substrates
- II.3 Experimental set up for the fabication of YBa2Cu3O7-8 thick films
- II.3.1 Screen Printing
- II.3.2 Dip-coating
- Fig 11.1 Schematic diagram of screen printing apparatus
- II.4 X-ray Powder Diffraction Technique
- Fig.II.2. Schematic diagram for the Debye Scherrer x-ray powder method
- II.5 Scanning Electron Microscope
- II.6 Electrical Measurements
- II.6.1 Resistivity and Critical Temperature Measurements-Vander-Pauw Method.
- Fig 11.5 Sample holder set up to measure the electrical resistivityof the samples.
- II.6.2 Critical Current Density Measurements
- II.7 Measurement of Dielectric Properties
- References
- III. Effect of Hafnium Oxide Addition in YBa2Cu3O7-8 Superconductors
- III.1.Introduction
- III.2 Sample Preparation
- III.3 Characterisation of Hf02 added YBa2Cu307-8 samples
- III.3.1 X-ray Diffraction Studies
- III.3.2 Temperature-Resistivity Measurements
- III.3.3 Surface Morphology
- Fig. III.3 Scanning Electron Micrograph of (A) pure YBCO (B) 5wt. % HfO, added YBCO (Magnification 2000)
- III.4 Enhanced Oxygen absorption in Hf02 added YBa2Cu3O7-8 samples
- III.4.1 Sample Preparation and Quenching Procedure
- III.4.2 Structural Analysis
- III.4.3 Temperature-Resistivity Measurements
- III.5 Discussion
- Referens
- IV. Synthesis and characterisation of REBa2HfO5.5 [RE=Y, Gd, Sm]-A new class of Ceramic Compounds
- IV. 1 Introduction
- IV.2 Preparation of REBa2HfO5.5
- IV.3 Crystal structure of REBa2HfO5.5
- Fig IV.2. Crystal structure diagram of KEBa2I-HfO5
- IV.4 Sintered Density and Resistivity Measurements
- IV.5 Measurement of Dielectric Properties
- IV.6 Surface Morphology of REBa2HfO5 5
- Fig.IV.7 Optical micrographs of (A) YBa2HfO, (B) GdBa2HfO,, (C) SmBa2HfO,, (Magnification 800)
- IV.7 Chemical Compatibility of REBa2HfO5 5 with YBa2Cu3O7-8
- IV.8 Discussions
- Referens
- V. Electrical Transport and Percolation study in YBa2Cu3O7-8 -REBa2HfO5.5Superconductor-Insulator Composite
- V.1 Introduction
- V.2 Percolation Model
- V.3 YBa2Cu3O7-8 YBa2HfO5 5 Percolation System
- V.3.1 Preparation of YBa2Cu3O7-8-YBa2HfO5 5 Composites
- V.3.2 X-ray Diffraction Studies on YBa2Cu3O7-8 YBa2HfO5 5 Composites
- V.3.3 Temperature-Resistivity Measurements on YBa2Cu3O7-8 YBa2HfO5 5 Composites
- V.4 YBa2Cu3O7-8-GdBa2HfO5 5 Percolation System
- V.4.1 Preparation of YBa2Cu3O7-8-GdBa, HfO5.5 Composites
- V.4.2 X-ray Diffraction Studies on YBa2Cu3O7-8 GdBa2HfO5 5 Composites
- V.4.3 Temperature-Resistivity Measurements on YBa2Cu3O7-8-GdBa2HfO5.5 Composites
- V.5 YBa2Cu3O7-8-SmBa2HfO5.5 Percolation System
- V.6 Percolation Study in YBa2Cu3O7-8 YBa2HfO5 5 Rapidly Quenched Samples
- V.7 Discussions
- References
- VI. Preparation of YBa2Cu3O7_SThick Films on REBa2HfO5 5 [RE=Y, Gd, Sm] Substrates by Screen Printing
- VI.1 Introduction
- VI.2 Screen Printing of YBa2Cu3O7-8Thick Films on REBa2HfO5 5 Substrates
- VI.3 Structural Characterisation of Screen Printed YBa2Cu3O7-8 Thick Films
- VI.4 Temperature-Resistivity Measurements of Screen Printed YBa2Cu30, -8Thick Films
- VI.5 Surface Morphology of Screen Printed YBa2Cu30, -8Thick Films
- VI 6 Discussions
- References
- VII. Fabrication of YBa2Cu30sThick Films on REBa2HfO5 s [RE= Y, Gd, Sm] Substrates by Dip coating
- VII.1 Introduction
- VII.2 Preparation of Dip coated YBa2Cu3O7-8Thick Films on REBa2HfO55 [RE= Y, Gd, Sm] on Substrates
- VII.3 X-ray Diffraction Analysis
- VII.4 Temperature-Resistivity Measurements
- VII.5 Microstructure of the Films
- VII.6 Discussions
- References
- VIII. Preparation of YBa2Cu3O7-8-Silver Composite Thick Films on REBa2HfO5 5 [R]E=Y, Gd, Sm] substrates
- VIII. 1 Introduction
- VIII. 2 Preparation of YBa2Cu3O7-8-Ag Composite
- VIII. 3 Preparation of YBa2Cu3O7-8-Ag Composite Thick Films on REBa2Hf05.5 [RE=Y, Gd, Sm] Substrates
- VIII. 4 X-ray Diffraction Studies on YBa2Cu3O7-8-Ag Composite Thick Films
- VIII. 5 Temperature-Resistivity Measurements
- VIII. 6 Micro structural Analysis
- VIII.7 Discussions
- References
- IX. Summary and Conclusions
- Scope of Future Investigations