CHEMISTRY OF SUPERCONDUCTOR MATERIALS Preparation, Chemistry, Characterization and Theory Edited by Terrell A. Vanderah Naval Weapons Center China Lake, California np NOYES PUBLICATIONS Park Ridge, New Jersey. U.S.A.
PARTI INTRODUCTION 1. HISTORICAL INTRODUCTION AND CRYSTAL CHEMISTRY OF OXIDE SUPERCONDUCTORS 2 Bertrand L. Chamberland 1. Introduction 2 1.1 Discovery of Superconductivity 4 1.2 Superconductivity A Brief Survey 4 1.3 Search Within the Chemical Elements- Pure Metals and the Elements 10 1.4 An Overview of the Superconducting Binary Alloy Systems 11 1.5 Ventures Into Ceramic Materials Binary Borides, Carbides, and Nitrides 15 1.6 Ventures Into Ceramic Oxides Simple Binary and Ternary Systems 17 1.7 Major Milestones in Oxide Superconductivity Research 21 1.8 Ternary Chemical Compounds Complex Borides and Sulfides 23 1.9 Non-Transition Metal Systems-(SN) X and Others 25 1.10 Organic Superconductors 28 2. Studies on Superconducting Oxides Prior to 1985 30 2.1 Studies of Superconducting Oxides with the Sodium Chloride Structure 30 xvii
xviii 2.2 Studies of Superconducting Oxides with the Perovskite-Type Structure 34 2.3 Studies of Superconducting Oxides with the Spinel Structure 49 2.4 Post-1985 Entry of Copper Oxide Superconductors 52 3. Structural Features and Chemical Principles in Copper Oxides 52 3.1 The Fascinating Chemistry of Binary and Temary Copper Oxides 52 3.2 Copper to Oxygen Bond Distances Ionic Radii.. 55 4. Physical Property Determination on Ternary Copper Oxides Studies on Copper Oxide Systems Prior to 1985 61 4.1 Studies on La 2 Cu0 4 and Its Derivatives 61 4.2 Startling Discovery by Müller and Bednorz 70 4.3 Corroboration of the Discovery and Further Developments 76 4.4 Major Copper Oxide Superconductors Presently Being Investigated 84 5. Chemical Substitutions Crystal Chemistry 84 5.1 Chemical Substitutions in the La 2 Cu0 4 Structure 84 5.2 Chemical Substitutions in the Perovskite Structure 84 6. References 93 PART II STRUCTURAL AND PREPARATIVE CHEMISTRY 2. THE COMPLEX CHEMISTRY OF SUPERCONDUCTIVE LAYERED CUPRATES 106 Bernard Raveau, Claude Michel, Maryvonne Hervieu, Daniel Groult 1. The Structural Principles 106 2. Oxygen Non-Stoichiometry and Methods of Synthesis 114 3. Extended Defects 124 3.1 Defects in YBa 2 Cu 3 0 7 124 3.2 Intergrowth Defects in Thallium Cuprates 129 4. Incommensurate Structures and Lone Pair Cations.. 133 5. Concluding Remarks 139 6. References 141
xix 3. DEFECTIVE STRUCTURES OF Ba 2 YCu 3 O x AND Ba 2 YCu 3. y M y O z (M = Fe, Co, AI, Ga,...) 146 Anthony Santoro 1. Introduction 146 2. Discussion of the Structure of Ba 2 YCu 3 O 70 147 2.1 Structural Changes as a Function of Oxygen Stoichiometry 150 2.2 Twinning, Twin Boundaries and Model of the Structure of Ba 2 YCu 3 0 7 0 154 2.3 Oxygen Vacancy Ordering in Ba 2 YCu 3 O x 161 2.4 Mechanisms of Oxygen Elimination From the Structure of Ba 2 YCu 3 O x 169 2.5 Metal Substitutions 174 3. References 185 4. CRYSTAL CHEMISTRY OF SUPERCONDUCTORS AND RELATED COMPOUNDS 190 Anthony Santoro 1. Introduction 190 2. Description of Layered Structures 191 2.1 Structural Types of Superconductors 200 2.2 Compounds with the Perovskite Structure 201 2.3 Compounds with Crystallographic Shear... 205 2.4 Compounds with the Rocksalt-Perovskite Structure 213 3. References 220 5. CRYSTAL GROWTH AND SOLID STATE SYNTHESIS OF OXIDE SUPERCONDUCTORS 224 Lynn F. Schneemeyer 1. Overview 224 2. Solid State Synthesis 224 2.1 Oxide Synthesis 225 2.2 Preparation of Samples Containing Volatile Constituents 227 2.3 Ceramic Characterization 228 3. Bulk Crystal Growth 229 3.1 Introduction to the Growth of Single Crystals.. 229 3.2 Flux Growth 232 3.3 Growth of Superconducting Oxides 236 3.4 Characterizing Single Crystals 247 4. References 250 6. PREPARATION OF BISMUTH- AND THALLIUM-
xx BASED CUPRATE SUPERCONDUCTORS 257 Stephen A. Sunshine and Terrell A. Vanderah 1. Introduction 257 2. Synthetic Methods 263 3. Synthesis of Bi-Based Cuprate Superconductors 265 3.1 Single Cu-O Layer Phase [2201], T c = 10 K... 265 3.2 Cu-O Double Layers [2212], T c = 80 K 266 3.3 Triple Cu-O Layers [2223], T c = 110 K 270 4. Synthesis of Thallium-Based Cuprate Superconductors 273 4.1 Preparations in Air or Lidded Containers 273 4.2 Preparations in Hermetically Sealed Containers 275 4.3 Preparations Under Flowing Oxygen 279 5. Conclusion 280 6. References 281 7. SYNTHESIS OF SUPERCONDUCTORS THROUGH SOLUTION TECHNIQUES 287 Phillipe Bafbonx 1. Introduction 287 1.1 Ceramic Processing 287 1.2 Interest in Solution Techniques 288 1.3 The Different Solution Techniques 289 2. Synthesis Procedures 289 2.1 General Principles of Synthesis 290 2.2 The Different Solution Processes 292 2.3 The Different Precursors 293 2.4 Thermal Processing 298 2.5 Carbon-Free Precursors 302 3. Conclusion 305 4. References 306 8. CATIONIC SUBSTITUTIONS IN THE HIGH T c SUPERCONDUCTORS 310 Jean Marie Tarascon and Brian G. Bagley 1. Introduction 310 2. Materials Synthesis 313 3. Results 314 3.1 La 2. x Sr x Cu0 4 314 3.2 YBa 2 Cu 3 0 7 322 3.3 Bi^CviCUnOy 328 4. Discussion 335 5. References 342
xxi 9. THE CHEMISTRY OF HIGH T c IN THE BISMUTH BASED OXIDE SUPERCONDUCTORS BaPb^L/^ AND Baj.jigBiOj 347 Michael L. Norton 1. Introduction 347 2. Theoretical Underpinnings of Bismuthate Research 348 3. Crystallography 354 4. Materials Preparation 355 4.1 Bulk Growth 355 4.2 Crystal Growth 356 4.3 Thin Film Preparation 358 5. Physical Properties 359 5.1 Electrical Transport Properties 359 5.2 Magnetic Properties 361 5.3 Optical and Infrared Properties 361 5.4 Specific Heat 362 5.5 Pressure Effects 363 5.6 Isotope Effects 364 6. Theoretical Basis for Future Bismuthate Research 365 7. Applications 367 8. Conclusion 369 9. References 369 10. CRYSTAL CHEMISTRY OF SUPERCONDUCTING BISMUTH AND LEAD OXIDE BASED PEROVSKITES 380 Robert J. Cava 1. Introduction 380 2. BaBi0 3 382 3. BaPb0 3 392 4. BaPh^jB^Oj 396 5. BaPbi.JSb^ 406 6. Ba 1. I K I Bi03 410 7. Conclusion 419 8. References 422 11. STRUCTURE AND CHEMISTRY OF THE ELECTRON- DOPED SUPERCONDUCTORS 427 Anthony C.W.P. James and Donald W. Murphy 1. Introduction 427 2. The T'-Nd 2 Cu0 4 Structure 428 3. Systematics of Electron Doping 431 4. Chemical Synthesis and Analysis 437
xxii 5. Single Crystals and Thin Films 442 6. Summary 444 7. References 445 PART III SAMPLE CHARACTERIZATION 12. X-RAY IDENTIFICATION AND CHARACTERIZATION OF COMPONENTS IN PHASE DIAGRAM STUDIES 450 /. Steven Swinnea and Hugo Steinfink 1. The Gibbs Phase Rule 451 2. Phase Diagrams 454 3. Phase Diagram Studies 464 4. X-Ray Diffraction 465 5. Tying It All Together 476 6. References 484 13. STRUCTURAL DETAILS OF THE HIGH T c COPPER- BASED SUPERCONDUCTORS 485 Charles C. Torardi 1. Introduction 485 2. Structures of the Perovskite-Related YBajCujO^ YBa 2 Cu 4 Og, and Y 2 Ba 4 Cu 7 0 15 Superconductors 488 2.1 123 Superconductor 488 2.2 124 and 247 Superconductors 490 3. Structures of the Perovskite/Rock Salt Superconductors 490 3.1 Lanthanum-Containing Superconductors 490 3.2 Bismuth-Containing Superconductors 491 3.3 Thallium-Containing Superconductors 493 3.4 Thallium-Lead Containing Superconductors... 495 4. Structures of Pb-Containing Copper-Based Superconductors 495 5. Distortions in the Rock Salt Layers and Their Effect on Electronic Properties 496 6. Correlations of T c with In-Plane Cu-O Bond Length.. 500 7. Tables of Crystallographic Information 501 8. References 541 14. CHEMICAL CHARACTERIZATION OF OXIDE SUPERCONDUCTORS BY ANALYTICAL ELECTRON MICROSCOPY 545 Anthony K. Cheetham and Ann M. Chippindale
xxüi 1. Introduction 545 2. Analytical Electron Microscopy: A Brief Survey 547 3. Experimental Method 548 4. Data Collection and Analysis of Standards 551 5. Analysis of the "2212" Compound (36) 554 6. Discussion 555 7. References 558 ELECTRON MICROSCOPY OF HIGH TEMPERATURE SUPERCONDUCTING OXIDES 561 Pratibha L. Gai 1. Introduction 561 2. Techniques of High Resolution Transmission Electron Microscopy (HREM), Transmission EM (TEM) Diffraction Contrast, and Analytical EM (AEM) 562 2.1 HREM 563 2.2 TEM Diffraction Contrast 564 2.3 High Spatial Resolution Analytical EM 564 3. Microstructural and Stoichiometric Variations 566 3.1 Substitutional Effects in La-Based Superconductors 566 3.2 Y-Based Superconductors 570 3.3 Substitution of Ca in Tetragonal YBa 2 Cu 3 0 6... 576 3.4 Bi-Based Superconductors 578 4. Tl-Based Superconductors 589 4.1 Tl-Ba-Ca-Cu-O Superconductors 591 4.2 (Tl,Pb)-Sr-Ca-Cu-0 Superconductors: (Tl,Pb)Sr 2 CaCu 2 0 7 (n=2) and (Tl,Pb)Sr 2 Ca 2 Cu 3 0 9 (n=3) 597 5. References 604 OXIDATION STATE CHEMICAL ANALYSIS 609 Daniel C. Harris 1. Superconductors Exist in Variable Oxidation States 609...And We Don't Know What Is Oxidized 610 2. Analysis of Superconductor Oxidation State by Redox Titration 611 2.1 Iodometric Titration Procedure 614 2.2 Citrate-Complexed Copper Titration Procedure 616 3. Reductive Thermogravimetric Analysis 616 4. Oxygen Evolution in Acid 619
xxiv 5. Eiectrochemical Investigation of Super- Conductor Oxidation State 621 6. Assessment of Analytical Procedures 624 7. References 624 17. TRANSPORT PHENOMENA IN HIGH TEMPERATURE SUPERCONDUCTORS 627 Donald H. Liebenberg 1. Introduction 627 2. Resistivity Measurement 627 2.1 Survey of Results of Resistivity Measurements.. 632 2.2 Theoretical Notes 637 3. Critical Current Density Measurements 639 3.1 Measurement of Critical Current 639 3.2 Results of Critical Current Measurements 645 4. Dissipation in the Intermediate State 652 5. Thermal Conductivity 656 6. Thermopower 657 7. Hall Effect 658 8. Tunneling Transport 660 8.1 Josephson Effect 662 8.2 Tunneling Results 663 9. References 667 18. STATIC MAGNETIC PROPERTIES OF HIGH- TEMPERATURE SUPERCONDUCTORS 675 Eugene L. Venturini 1. Introduction 675 2. Low-Field Measurements 677 2.1 Normal State Response 677 2.2 Diamagnetic Shielding by a Superconductor... 681 2.3 Magnetic Flux Exclusion and Expulsion 687 3. High-Field Measurements: Hysteresis Loops and Critical Current Density 691 4. Magnetization Relaxation or Giant Flux Creep 696 5. Problems with Porous and Weak-Linked Ceramics... 700 6. Concluding Remarks 705 7. References 706 PART IV STRUCTURE-PROPERTY CONSIDERATIONS 19. ELECTRONIC STRUCTURE AND VALENCY IN OXIDE SUPERCONDUCTORS 714
xxv Arthur W. Sleight 1. Introduction 714 2. Mixed Valency and the Partially Filled Band 714 3. Valent States vs Real Charges 718 4. Stabilization of 0~ n and High Oxidation States 720 5. Polarizibility 721 6. Defects and Inhomogeneities 723 7. Stability 726 8. T c Correlations 729 9. Mechanism for High T c 731 10. References 733 20. ELECTRON-ELECTRON INTERACTIONS AND THE ELECTRONIC STRUCTURE OF COPPER OXIDE- BASED SUPERCONDUCTORS 735 Jeremy K. Burdett 1. Introduction 735 2. One- and Two-EIectron Terms in the Energy 736 3. Energy Bands of Solids 748 4. The Peierls Distortion 753 5. Antiferromagnetic Insulators 756 6. Electronic Structure of Copper Oxide Superconductors 759 7. The Orthorhombic-Tetragonal Transition in 2-1-4... 766 8. Superconductivity and Sudden Electron Transfer... 770 9. Some Conclusions 773 10. References 774 APPENDIX A: GUIDE TO SYNTHETIC PROCEDURES 776 APPENDIX B: FURTHER READING IN SUPERCONDUCTIVITY AND SOLID STATE CHEMISTRY 784 FORMULA INDEX 790 SUBJECT INDEX 802