University of Northern Iowa UNI ScholarWorks Dissertations and Theses @ UNI Student Work 1996 An investigation on the processing and characterization of (thallium(0.5-x) lead(0.5-x) europium(2x)) strontium(2-y) barium(y) calcium(2) copper(3) oxygen(z) high-temperature superconductor to determine the optimum barium concentration and study the effects of doping europium in thallium and lead sites Zifan Ju University of Northern Iowa Let us know how access to this document benefits ouy Copyright ©1996 Zifan Ju Follow this and additional works at: https://scholarworks.uni.edu/etd Part of the Semiconductor and Optical Materials Commons Recommended Citation Ju, Zifan, "An investigation on the processing and characterization of (thallium(0.5-x) lead(0.5-x) europium(2x)) strontium(2-y) barium(y) calcium(2) copper(3) oxygen(z) high-temperature superconductor to determine the optimum barium concentration and study the effects of doping europium in thallium and lead sites" (1996). 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Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. An investigation on the Processing and Characterization of (Tig_5 _xPb Q .5 -xEu2 x^Sr2 -yBayCa2 Cu 3 0 2 High Temperature Superconductor to Determine the Optimum Ba Concentration and Study the Effects of Doping Europium in Tl & Pb Sites A Dissertation Submitted In partial Fulfillment of the Requirements for the Degree of Doctor of Industrial Technology Approved By: Dr. Mohammed F. Fahmy (Advisor) Dr. Douglas T. Pine (co-Aavisorj Dr. Guru Subramanyam Dr. Eugene WallitjgJord Dr. Syed Kirmani Zifan Ju University of Northern Iowa May 1996 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 9701105 Copyright 1996 by Ju, Zifan All rights reserved. UMI Microform 9701105 Copyright 1996, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Copyright by ZIFAN JU May 1996 All Right Reserved Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Dedicated to My wife JIN, GUANG and to My sons JU, REX BEN and JU, ROY BEN Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGMENTS The author would like to acknowledge the guidance and encouragement of Dr. Mohammed F. Fahmy, advisor, Dr. Douglas T. Pine, co-advisor, Dr. Guru Subramanyam, Dr. Paul M. Shand, Dr. Eugene Wallingford and Dr. Syed Kirmani. Without their continuous advice and assistance for this research, this study would have been impossible. Special thanks would be given to Dr. Guru Subr amanyam, who spent a lot of time and gave much support for this research. Dr. Paul M. Shand also deserves special appreciation for providing the AC Susceptometer for sample measurement. The author also wishes to express his gratitude to the College of Nature Sciences, University of Northern Iowa for the research funding. The greatest debt is owed to my wife and my family, without their steady spiritual support, this study could never have been done. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS Page LIST OF TABLES............................................. V LIST OF FIGURES.......................................... vii CHAPTER I INTRODUCTION..................................... 1 Statement of Problem.................................... 2 Statement of Purpose.................................... 3 Significance of the Study ............................... 3 Research Questions ..................................... 4 Definition of Terms ..................................... 5 CHAPTER II REVIEW OF LITERATURE............................ 8 Research Background..................................... 8 Characteristics of Superconductors .................... 11 Applications of Superconductivity...................... 13 Thallium-Barium-Copper Oxide and Related Compounds...... 16 Thallium System Superconductor...................... 16 The Role of Copper-Oxide............................ 24 The Role of the Pb in Superconductors................ 26 Sample Preparation ................................. 27 Characterization of Superconductors ................... 29 CHAPTER III METHODOLOGY................................... 31 Test Procedure......................................... 31 Sample Preparation Procedure........................... 31 Sample Measurement and Analysis Procedure............... 32 X-Ray Diffraction Analysis ......................... 33 Magnetic Susceptibility Analysis .....................39 AC Susceptibility Measurement — LakeShore 7000 ...... 41 7000 Series Susceptometer System.....................44 CHAPTER IV REPORT OF FINDINGS, ANALYSIS OF DATA AND RESULTS........................................ 49 Optimizing Sample Fabrication Process .................. 49 Precursor Preparation Process ...................... 49 Final Sample Preparation and Sintering Process ...... 51 Ba Doping Only .................................... 51 Ba Doping and Eu Doping in Tl, Pb Site ............. 53 Optimizing Ba Doping Process........................... 71 Optimizing Eu Doping Process .......................... 86 Results and Discussions................................ 96 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. iv Page CHAPTER V CONCLUSIONS.................................... 105 Summary............................................... 105 Statement of the Problem ........................... 105 Significance of the Study .......................... 105 Methodology ........................................ 106 Findings ........................................... 107 Conclusions..................................... 108 Recommendations....................................... 109 REFERENCES............................................... Ill APPENDICES............................................... 115 Appendix A. AC susceptibility measurement results for Ba Doping................................ 115 Appendix B. AC susceptibility measurement results for Eu Doping................................ 128 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. V LIST OF TABLES Page Table 1. History of Oxide Superconductors................ 10 Table 2. Superconducting Thallium-copper-oxides...........17 Table 3. Summary of Tl-System Related Dissertation Research........................................ 18 Table 4. XRD Peaks for Various Phases.................... 38 Table 5. Calculations for Precursor with Ba Doping........50 Table 6 . TlO and PbO Calculation for Final Samples........52 Table 7. Calculations Results for 0.2500gm Final Samples. 54 Table 8 . Summmary Chart of Tc, Volume Fraction and Phase Purity.......................................... 72 Table 9. Summary of Tc, Phase Purity and Superconductor Properties for Eu Doping.........................93 Table 10. (TlPbSrCaCuO) with Ba Doping Ba = 0.00.......... 116 Table 11. (TlPbSrCaCuO) with Ba Doping Ba = 0.10.......... 117 Table 12. (TlPbSrCaCuO) with Ba Doping Ba = 0.20.......... 118 Table 13. (TlPbSrCaCuO) with Ba Doping Ba = 0.30.......... 119 Table 14. (TlPbSrCaCuO) with Ba Doping Ba = 0.40.......... 120 Table 15. (TlPbSrCaCuO) with Ba Doping Ba = 0.50.......... 121 Table 16. (TlPbSrCaCuO) with Ba Doping Ba =