High temperature superconductor bulk materials: fundamentals- processing- properties control- application aspects

High Temperature Superconductor Bulk Materials......Page 4
Contents......Page 8
Preface......Page 14
1.1.1 Introductory Remarks......Page 16
1.1.3 Critical Currents and Flux Motion in Superconductors......Page 18
1.1.4 Magnetization Curve of a Type II Superconductor......Page 22
1.1.5 Determination of Critical Currents from Magnetization Loops......Page 24
1.1.6 Magnetic Relaxation......Page 26
1.1.7 Electric Field–Current Relation......Page 28
1.1.8 Peculiarities of HTSCs in Comparison to Low-Temperature Superconductors......Page 30
1.1.9 Basic Relations for the Pinning Force and Models for its Calculation......Page 31
1.2 Features of Bulk HTSCs......Page 33
1.2.1 Bulk HTSCs of Large Dimensions......Page 34
1.2.2 Potential of Bulk HTSC for Applications......Page 35
1.3.1 Crystal Structures and Functionality......Page 37
1.3.2 Chemistry and Doping......Page 39
1.3.3 Intrinsic Doping: Variations of Stoichiometry......Page 40
1.3.4 Defect Chemistry......Page 41
1.3.5 Extrinsic Doping......Page 42
2.1.1 Phase Diagrams and Fundamental Thermodynamics......Page 46
2.1.2 Subsolidus Phase Relationships......Page 48
2.1.3 The Influence of Oxygen on Phase Equilibria: the System Y-Ba-Cu-O......Page 50
2.1.4 The Oxygen Nonstoichiometry in 123 phases: YBa(2)Cu(3)O(7–Δ) (YBa(2)Cu(3)O(6+x))......Page 52
2.1.5 Phase Relationships in Y-Ba-Cu-O in the Solidus and Liquidus Range......Page 54
2.1.6 Phase Relationships and the Liquidus Surface in Systems Ln-Ba-Cu-O (Ln = Nd, Sm,.. )......Page 57
2.2.1 Synthesis of HTSC Compounds......Page 60
2.3 Growth of YBa(2)Cu(3)O(7) Single Crystals......Page 61
2.4.1 Experimental Procedure......Page 62
2.4.2 Mass Flow, Growth Rates, Kinetic and Constitutional Undercooling......Page 65
2.4.3 Developing Microstructures: Morphology, Inclusions, Defects......Page 68
2.5.2 Processing Mixtures of Y123 and Yttria......Page 75
2.5.3 Processing in Reduced Oxygen Partial Pressure......Page 78
3 Pinning-Relevant Defects in Bulk YBCO......Page 82
4.1.1 Irreversibility Fields......Page 90
4.1.2 Upper Critical Fields......Page 93
4.1.3 Vortex Matter Phase Diagram......Page 94
4.2.1 Transport Measurements......Page 97
4.2.2 Magnetization Measurements......Page 98
4.3.1 Flux Creep in Bulk YBCO......Page 101
4.3.2 Reduction of Flux Creep......Page 102
4.3.3 Pinning Properties from Relaxation Data......Page 104
4.4.1 Basic Relations......Page 106
4.4.2 Mechanical Data for Bulk YBCO......Page 108
4.5.1 Symmetry of the Order Parameter......Page 111
4.5.2 Specific Heat......Page 113
4.5.3 Thermal Expansion......Page 114
4.5.4 Thermal Conductivity......Page 116
5.2 Bulk HTSC at 77 K......Page 120
5.3 Trapped Field Data at 77 K......Page 124
5.4 Limitation of Trapped Fields in Bulk YBCO at Lower Temperatures......Page 125
5.4.1 Magnetic Tensile Stress and Cracking......Page 126
5.4.2 Thermomagnetic Instabilities......Page 128
5.5 Magnetizing Superconducting Permanent Magnets by Pulsed Fields......Page 130
5.6 Numerical Calculations of the Local Critical Current Density from Field Profiles......Page 134
5.6.1 Inverse Field Problem: Two-Dimensional Estimation......Page 135
5.6.2 Three-Dimensional Estimation......Page 137
5.7 Visualization of Inhomogeneities in Bulk Superconductors......Page 140
6.1.1 Chemical Modifications in YBa(2)Cu(3)O(7)......Page 144
6.1.2 Sub-Micro Particles Included in Bulk YBCO......Page 150
6.1.3 Irradiation Techniques......Page 151
6.2.1 Fundamentals of the Processing and Growth of YBCO/Ag Composite Materials......Page 153
6.2.2 Processing and Results......Page 155
6.2.3 Properties of Bulk YBaCuO/Ag Composite Materials......Page 156
6.3 Near Net Shape Processing: Large Sized Bulk Superconductors and Functional Elements......Page 157
6.3.1 Finishing and Shaping......Page 158
6.3.3 Rings of 123 Bulk Materials......Page 159
6.3.4 Joining of Separate Single Grains......Page 161
6.4.1 Infiltration Technique and Foams......Page 163
6.4.2 Long-Length Conductors and Controlled-Resistance Materials......Page 164
6.4.4 Batch Processing of 123 Bulk Materials......Page 166
7.1 Impact of Solid Solutions Ln(1+y)Ba(2–y)Cu(3)O(7±Δ) on Phase Stability and Developing Microstructure......Page 170
7.2.1 Oxygen Potential Control......Page 175
7.2.3 Isothermal Growth Process at Variable Oxygen Partial Pressure (OCIG)......Page 176
7.2.4 Composition Control in Oxidizing Atmosphere for Growing (CCOG)......Page 178
7.4 Further LnBa(2)Cu(3)O(7)-Based Materials......Page 180
7.5.1 Fundamentals of Processing......Page 181
7.5.2 Reactions Near the Seed–Melt Interface......Page 182
7.5.3 Growth and Properties of Ag/LnBaCuO Composites......Page 183
8 Peak Effect......Page 186
8.1 Peak Effect (due to Cluster of Oxygen Vacancies) in Single Crystals......Page 187
8.2 Peak Effect in Bulk HTSC......Page 190
9.1.1 Magnetic Tensile Stress (in Reinforced YBCO Disks)......Page 194
9.1.2 Trapped Field Measurements......Page 196
9.2 Resin-Impregnated YBCO......Page 199
9.3 Trapped Field Data of Steel-reinforced YBCO......Page 200
9.4 Comparison of Trapped Field Data......Page 203
10 Engineering Aspects: Field Distribution in Bulk HTSC......Page 206
10.1.1 Field Cooling......Page 207
10.1.2 Zero-Field Cooling......Page 208
10.2.1 Field Cooling......Page 209
10.2.2 Zero-Field Cooling......Page 210
11.1.1 Introduction to Magnetic Levitation......Page 214
11.1.2 Attributes of Superconducting Magnetic Bearings with Bulk HTSC......Page 215
11.2.1 Forces in the Meissner and the Mixed State......Page 216
11.2.2 Maximum Levitational Pressure in Superconducting Bearings......Page 219
11.3.1 Cooling Modes......Page 222
11.3.2 Operational Field Cooling with an Offset......Page 224
11.3.4 Magnet Systems for Field Excitation in Superconducting Bearings......Page 226
11.3.5 Force Characteristics......Page 231
11.4 Optimized Flux Concentration Systems for Operational-Field Cooling (OFCo)......Page 235
11.4.2 Dimensional Optimization of System Components......Page 236
11.5.1 Critical Current Density......Page 240
11.5.2 Temperature......Page 241
11.5.3 Flux Creep......Page 242
11.5.4 HTSC Bulk Elements Composed of Multiple Isolated Grains......Page 244
11.5.5 Number of Poles of the Excitation System......Page 247
11.6 Applications of Superconducting Bearings......Page 248
11.6.1 Bearings for Stationary Levitation......Page 249
11.6.2 Bearings for Rotary Motion......Page 251
11.6.3 Bearings for Linear Motion......Page 256
11.7.1 Precise Positioning of Horizontal Rotating Axis......Page 260
11.7.2 Bulk HTSCs Cooled Below 77 K......Page 261
11.7.4 Dynamics of Rotating Superconducting Bearings......Page 262
11.8 Numerical Methods......Page 264
11.8.1 Perfectly Trapped Flux Model (2D)......Page 265
11.8.2 Perfectly Trapped Flux Model (3D)......Page 267
11.8.3 Vector-Controlled Model (2D)......Page 268
12.1 Design Principles......Page 274
12.2 Basic Demonstrator for Application in Electrical Machines – Hysteresis or Induction Machines......Page 276
12.3 Trapped-Field Machine Designs......Page 278
12.4 Stator-Excited Machine Designs with Superconducting Shields – The Reluctance Motor with Bulk HTSC......Page 284
12.5 Machines with Bulk HTSCs – Status and Perspectives......Page 288
13.1.1 Laboratory Magnets......Page 294
13.1.2 Magnetic Separators......Page 295
13.1.3 Sputtering Device......Page 298
13.2 High-Temperature Superconducting Current Leads......Page 299
13.3 Superconducting Fault Current Limiters......Page 300
13.3.1 Inductive Fault Current Limiters......Page 301
13.3.2 Resistive Superconducting Fault Current Limiters......Page 302
13.3.3 Status of High AC Power SFCL Concepts......Page 303
13.4 High-Temperature Superconducting Magnetic Shields......Page 305
List of Abbreviations......Page 308
Index......Page 310