Flux Pinning in Superconductors (eBook)

Preface 5
Contents 10
1 Introduction 14
1.1 Superconducting Phenomena 14
1.2 Kinds of Superconductors 16
1.3 London Theory 19
1.4 Ginzburg-Landau Theory 22
1.5 Magnetic Properties 29
1.6 Surface Superconductivity 43
1.7 Josephson Effect 45
1.8 Critical Current Density 47
1.9 Flux Pinning Effect 51
Exercises 51
References 53
2 Fundamental Electromagnetic Phenomena in Superconductors 54
2.1 Equations of Electromagnetism 54
2.2 Flux Flow 58
2.3 Mechanism of Hysteresis Loss 64
2.4 Characteristic of the Critical State Model and its Applicable Range 67
2.5 Irreversible Phenomena 68
2.6 Effect of Diamagnetism 79
2.7 AC Losses 89
Exercises 94
References 95
3 Various Electromagnetic Phenomena 97
3.1 Geometrical Effect 97
3.2 Dynamic Phenomena 107
3.3 Superposition of AC Magnetic Field 109
3.4 Flux Jump 115
3.5 Surface Irreversibility 120
3.6 DC Susceptibility 131
3.7 Reversible Flux Motion 137
3.8 Flux Creep 150
Exercises 163
References 164
4 Longitudinal Magnetic Field Effect 166
4.1 Outline of Longitudinal Magnetic Field Effect 166
4.2 Flux-Cutting Model 172
4.3 Stability of the Force-Free State 179
4.4 Motion of Flux Lines 186
4.5 Critical Current Density 197
4.6 Generalized Critical State Model 202
4.7 Resistive State 205
Exercises 217
References 218
5 Measurement Methods for Critical Current Density 220
5.1 Four Terminal Method 220
5.2 DC Magnetization Method 223
5.3 Campbell’s Method 224
5.4 Other AC Inductive Methods 232
Exercises 242
References 242
6 Flux Pinning Mechanisms 243
6.1 Elementary Pinning and the Summation Problem 243
6.2 Elementary Pinning Force 244
6.3 Condensation Energy Interaction 247
6.4 Elastic Interaction 263
6.5 Magnetic Interaction 268
6.6 Kinetic Energy Interaction 269
6.7 Improvement of Pinning Characteristics 271
Exercises 273
References 274
7 Flux Pinning Characteristics 276
7.1 Flux Pinning Characteristics 276
7.2 Elastic Moduli of Flux Line Lattice 280
7.3 Summation Problem 284
7.4 Comparison with Experiments 306
7.5 Saturation Phenomenon 319
7.6 Peak Effect and Related Phenomena 331
7.7 Pinning Potential Energy 340
Exercises 345
References 346
8 High-Temperature Superconductors 349
8.1 Anisotropy of Superconductors 349
8.2 Phase Diagram of Flux Lines 353
8.3 Weak Links of Grain Boundaries 369
8.4 Electromagnetic Properties 373
8.5 Irreversibility Field 388
8.6 Flux Pinning Properties 402
Exercises 417
References 417
9 MgB2 421
9.1 Superconducting Properties 421
9.2 Flux Pinning Properties 423
9.3 Possibility of Improvements in the Future 438
Exercises 440
References 441
A Appendix 443
A.1 Description of Equilibrium State 443
A.2 Magnetic Properties of a Small Superconductor 445
A.3 Minimization of Energy Dissipation 447
A.4 Partition of Pinning Energy 448
A.5 Comments on the Nonlocal Theory of the Elasticity of the Flux Line Lattice 449
A.6 Avalanching Flux Flow Model 456
A.7 Josephson Penetration Depth 460
A.8 On the Transverse Flux Bundle Size 460
References 469
Answers to Exercises 470
Chapter 1 470
Chapter 2 474
Chapter 3 481
Chapter 4 488
Chapter 5 492
Chapter 6 494
Chapter 7 495
Chapter 8 502
Chapter 9 504
References 504
Index 505