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Thermodynamic Critical Field and Superconducting Fluctuation of Vortices for High Temperature Cuprate Superconductor: La-214 " (2001)

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Thermodynamic Critical Field and Superconducting Fluctuation of Vortices for High Temperature Cuprate Superconductor: La-214 Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2001 Thermodynamic critical field nda superconducting fluctuation of vortices for high temperature cuprate superconductor: La-214 Yung Moo Huh Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Condensed Matter Physics Commons Recommended Citation Huh, Yung Moo, "Thermodynamic critical field and superconducting fluctuation of vortices for high temperature cuprate superconductor: La-214 " (2001). Retrospective Theses and Dissertations. 1047. https://lib.dr.iastate.edu/rtd/1047 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. ProQuest Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 Thermodynamic critical field and superconducting fluctuation of vortices for high temperature cuprate superconductor: La-214 by Yung Moo Huh A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Condensed Matter Physics Major Professor: Douglas K. Finnemore Iowa State University Ames, Iowa 2001 UMI Number: 3016712 UMI <§) UMI Microform 3016712 Copyright 2001 by Bell & Howell Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 ii Graduate College Iowa State University This is to certify that the Doctoral dissertation of Yung Moo Huh has met the dissertation requirements of Iowa State University Signature was redacted for privacy. Committee Member Signature was redacted for privacy. Commit Member Signature was redacted for privacy. ommittee Member Signature was redacted for privacy. Committ ember Signature was redacted for privacy. Major Professor Signature was redacted for privacy. For the Major Program Signature was redacted for privacy. For th Graduate College iii This dissertation is dedicated to my wife, Kyusung Kim and son, Richard Kim Huh and to those who prayed for Richard with thanks. iv TABLE OF CONTENTS LIST OF TABLES vi LIST OF FIGURES vii NOMENCLATURE xiv ABSTRACT xvi CHAPTER 1. GENERAL INTRODUCTION 1 I. Introduction 1 II. Brief History of Superconductivity 2 III. Dissertation Organization 5 References 6 CHAPTER 2. THEORY AND MODELS 10 I. Thermodynamic Critical Field 10 II. Reversible Magnetization 15 III. Scaling Theory of Fluctuation of Vortices 21 References 22 CHAPTER 3. EXPERIMENTS 24 I. Introduction 24 II. Sample Preparation 28 References 34 CHAPTER 4.REVERSIBLE MAGNETIZATION AND SUPERCONDUCTING STATE THERMODYNAMIC PARAMETERS FOR UNDERDOPED Lai.9oSro.ioCu04 36 Abstract 36 I. Introduction 37 II. Experiment 41 III. Results and Discussion 42 IV. Conclusion 52 Acknowledgment 54 References 54 V CHAPTER 5. THERMODYNAMIC CRITICAL FIELD FOR La2-xSrxCu04 58 Abstract 58 I. Introduction 59 II. Experiment 63 III. Results and Discussion 64 A. Normal-State Properties 66 B. Superconducting State Magnetization 69 C. BCS Thermodynamics 92 IV. Conclusion 101 Acknowledgment 102 Appendix: Calculation of A(0)/ksTc and y 102 References 112 CHAPTER 6. SUPERCONDUCTING FLUCTUATION OF VORTICES FOR La2-xSrxCu04 116 Abstract 116 I. Introduction 117 EL Experiment 123 III. Results and Discussion 124 A. Strongly Underdoped Regime: x = 0.070 and 0.081 124 B. Slightly Underdoped Regime: x = 0.100 and 0.117 133 C. Near Optimum Doped Regime: x = 0.143 and 0.156 139 IV. Conclusion 148 Acknowledgment 149 References 149 CHAPTER 7. GENERAL CONCLUSION 153 ACKNOWLEDGMENTS 156 BIOGRAPHICAL SKETCH 157 vi LIST OF TABLES Table 5.1 Transition temperatures and Meissner shielding fractions of single crystals and magnetically aligned powder samples of La2-xSrxCuC>4. 65 Table 5.2 Normal state fitting parameters in Mn = CH + Ms tanh(/?ti). 70 Table 5.3 Normal state fitting parameters in C = %o + AT + B/(T + 0). 74 Table 5.4 Thermodynamic parameters from the Two-Fluid Model. 90 Table 5.5 Thermodynamic parameters from the BCS theory. 98 Table 5.A1 The values of AlknTc and y from this work. They are compared with the results of Ref. 27. 109 Table 6.1 Thermodynamic parameters used to fit the scaling function. 129 Table 6.2 Crossing temperatures and dimensions in the corresponding field ranges for the strongly underdoped, slightly underdoped and optimum doped regimes. The scaling of low field data for x = 0.143 and 0.156 does not show clear-cut dimensionality. 145 vii LIST OF FIGURES Figure 2.1 (a) Hc(T) for the s-p band metal superconductors. 12 Figure 2.1 (b) Hc{T) for the d band metal superconductors. 12 Figure 2.2 The BCS theory prediction (solid line) and empirical results for the elemental superconductors. 14 Figure 2.3 (a) Sketch of the Abrikosov high field approximation. Magnetization has the constant slope near HC2 with increasing field. 20 Figure 2.3 (b) Sketch of the Hao-Clem model. Field-dependent slopes are seen. 20 Figure 2.3 (c) Sketch of the modified London model. There exists a unique crossing point. 20 Figure 3.1 The crystal structure of La2-xSrxCuC)4 [from Ref. 2]. 25 Figure 3.2 Structural and magnetic phase diagram of La2-xSrxCu04 [from Ref. 4]. 27 Figure 3.3 (a) The x-ray image in c-direction for La1.90Sr0.10Cu.O4. 29 Figure 3.3 (b) The x -ray image in c-direction for Lai.9oSro.ioCu04. 29 Figure 3.4 (a) The x -ray image perpendicular to c-axis for Lai.9oSro.ioCu04. 30 Figure 3.4 (b) The x -ray image perpendicular to c-axis for Lai.9oSro.ioCu04. 30 viii Figure 3.5 Transition, temperatures of La2-xSrxCu04. The triangles are for single crystals and the circles are for aligned powder samples. 33 Figure 4.1 Normal state magnetization every 20 K from 60 to 200 K. The solid lines are fits of the data to Eq. (1). The inset expands the low-field portion. 43 Figure 4.2 Superconducting magnetization curves every 2 K from 8 to 30 K showing Abrikosov-like behavior below 18 K and fluctuation-like behavior above 22K. 45 Figure 4.3 Magnetization vs. temperature showing the crossover at 22 K. Data are plotted every half Tesla from 1.0 to 7.0 T. 47 Figure 4.4 2D scaling behavior of the magnetization every half Tesla from 3.0 to 7.0 T. 49 Figure 4.5 Thermodynamic critical field He vs. T determined from three different ways. The inset shows a fit of the data from 6 to 12 K to the universal Hao-Clem curve for KC = 175. 51 Figure 5.1 (a) The low field susceptibilities of underdoped La2-xSrxCu04. 67 Figure 5.1 (b) The low field susceptibilities of overdoped La2-xSrxCuC>4. 67 Figure 5.2 Normal state magnetization at 80 K for different Sr contents of La2-xSrxCu04. 68 Figure 5.3 Temperature dependence of C. Solid lines are normal state susceptibilities from Ref. 7 for La2-xSrxCu04. 71 ix Figure 5.4 Irreversibility field lines of La2-xSrxCu04. 72 Figure 5.5 The background signal Mn and total reversible magnetization Mt at 18 K (< Tc) of La1.90Sr0.10Cu.O4. 75 Figure 5.6 The superconducting magnetization Msc = Mt - Mn at 23 K of La2-xSrxCu04. 76 Figure 5.7 (a) The Hao-Clem curve for KC = 60 from 12 to 20 K. The inset shows the Hc(T) with the Two-Fluid model curve for Lai.87Sro.mCu04. 78 Figure 5.7 (b) The Hao-Clem curve for KC = 91 from 21 to 28 K. The inset shows the Hc(T) with the Two-Fluid model curve for La1.844Sro.156Cu.O4. 79 Figure 5.8 (a) The Hc(T) with the Two-Fluid model curves for the underdoped and optimum doped La2-xSrxCu04. 80 Figure 5.8 (b) The Hc{T) with the Two-Fluid model curves for the overdoped La2-xSrxCu04. 81 Figure 5.9 (a) The low field susceptibilities of 0.15 series of La2-xSrxCu04. 82 Figure 5.9 (b) The HC(T), Meissner shielding fraction, and Tco of 0.15 series. 82 Figure 5.10 The Tco vs. Hc(0) plot of La2-xSrxCuO4. Refer to Table 5.4 for unmarked data. 84 Figure 5.11 Magnetization below Tco (= 8 K) of Lai.94Sro.oeCu04.
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