Vortices and Nanostructured Superconductors (eBook)

Adrian Crisan (Herausgeber)

eBook Download: PDF

2017 | 1st ed. 2017
XIV, 259 Seiten
Springer International Publishing (Verlag)
978-3-319-59355-5 (ISBN)

Infos

This book provides expert coverage of modern and novel aspects of the study of vortex matter, dynamics, and pinning in nanostructured and multi-component superconductors. Vortex matter in superconducting materials is a field of enormous beauty and intellectual challenge, which began with the theoretical prediction of vortices by A. Abrikosov (Nobel Laureate). Vortices, vortex dynamics, and pinning are key features in many of today's human endeavors: from the huge superconducting accelerating magnets and detectors at the Large Hadron Collider at CERN, which opened new windows of knowledge on the universe, to the tiny superconducting transceivers using Rapid Single Flux Quanta, which have opened a revolutionary means of communication.

In recent years, two new features have added to the intrinsic beauty and complexity of the subject: nanostructured/nanoengineered superconductors, and the discovery of a range of new materials showing multi-component (multi-gap) superconductivity. In this book, leading researchers survey the most exciting and important recent developments in the field.  Topics covered include: the use of scanning Hall probe microscopy to visualize interactions of a single vortex with pinning centers; Magneto-Optical Imaging for investigating what vortex avalanches are, why they appear, and how they can be controlled; and the vortex interactions responsible for the second magnetization peak. Other chapters discuss nanoengineered pinning centers of vortices for improved current-carrying capabilities, current anisotropy in cryomagnetic devices in relation to the pinning landscape, and the new physics associated with the discovery of new superconducting materials with multi-component superconductivity. The book offers something for almost everybody interested in the field: from experimental techniques to visualize vortices and study their dynamics, to a state-of-the-art theoretical microscopic approach to multicomponent superconductivity.

Inhalt

Preface 6
Contents 11
Contributors 12
1 Vortex Deformation Close to a Pinning Center 14
1.1 Introduction 14
1.2 Experimental 15
1.2.1 Distribution of Pinning Centers 16
References 24
2 Pinning-Engineered YBa2Cu3Ox Thin Films 27
2.1 Introduction 27
2.2 Critical Current and Pinning Force in Pure YBa2Cu3Ox Thin Films 29
2.3 Critical Current and Pinning Force in YBa2Cu3Ox Thin Films with Artificial Pinning Centers (APCs) 31
2.3.1 Zero-Dimensional APCs (0D-APCs) 34
2.3.2 One-Dimensional APCs (1D-APCs) 36
2.3.2.1 Columnar Defects by Neutron and Ion Irradiation 37
2.3.2.2 Linear APCs in YBCO Films Deposited on Decorated Substrates and on Functional Buffers 38
2.3.2.3 Oxide Nanocolumns Embedded in Superconducting Films 40
BaZrO3 (BZO) Nanocolumns 43
BaSnO3 (BSO) Nanocolumns 45
BaHfO3 (BHO) Nanocolumns 51
Other Oxide Nanocolumns 52
2.3.3 Two-Dimensional APCs (2D-APCs) 52
2.3.3.1 Nanolayers as 2D-APCs 53
2.3.3.2 Grain Boundaries as 2D-APCs 54
2.3.4 Three-Dimensional APCs (3D-APCs) 55
2.3.5 Segmented 1D-APCs 61
2.3.6 Combined One-Dimensional and Three-Dimensional (1D+3D) APCs 62
2.3.6.1 Hybrid YBCO Films with Mixed 1D+3D-APCs 63
2.3.6.2 Multilayers with Alternate YBCO+1D-APCs and YBCO+3D-APCs Layers 64
2.3.7 Combination of APCs Parallel (Nanorods) and Perpendicular (Nanolayers) to C-axis of YBCO Film 65
2.4 Conclusion 66
Acknowledgements 67
References 68
3 Chemically and Mechanically Engineered Flux Pinning for Enhanced Electromagnetic Properties of MgB2 76
3.1 Impurities as Flux Pinning Centers 76
3.1.1 Introduction 76
3.1.2 Oxide Phases in Undoped MgB2 Bulks 81
3.1.2.1 Sources of Oxidation 81
3.1.2.2 Types of MgB2 Samples 83
3.1.3 Oxides Doping 85
3.1.3.1 Graphene Oxide 86
3.1.3.2 Rare Earth Oxides 87
3.1.3.3 Other Oxide Dopants 88
3.1.3.4 Samples Prepared Using Spark Plasma Sintering (SPS) 90
3.1.3.5 Samples Prepared Using Mechanical Alloying and Hot Pressing 91
3.1.3.6 Co-additions 92
3.2 Carbon Impurity Doping 92
3.2.1 Why Carbon Doping? 92
3.2.2 Carbon Doping Effect 93
3.2.3 Carbon Doping Methodology 97
3.3 Ball Milling 101
3.3.1 Introduction 101
3.3.2 Ex Situ Processed Materials 103
3.3.3 In Situ Processed Materials 105
3.3.4 Mechanical Alloying 106
3.3.5 Mechanical Alloying with Dopants 107
3.4 Concluding Remarks 108
Acknowledgements 108
References 109
4 Critical Current Anisotropy in Relation to the Pinning Landscape 120
4.1 Introduction 120
4.2 Mass Anisotropy Scaling 122
4.2.1 Theory 122
4.2.2 {/bi J}_{{/bi c}} ( {{/bi h}/left({/varvec /theta}/right)} ) Scaling of YBCO 123
4.2.3 {/bi J}_{{/bi c}} ( {{/bi h}/left({/varvec /theta}/right)} ) Scaling of BSCCO 127
4.2.4 {/bi F}_{{/bi p}} ( {{/bi h}/left({/varvec /theta}/right)} ) Scaling of Ba-122 128
4.3 Models of Pinning and Field Angle-Dependent Currents 131
4.3.1 The Tachiki and Takahashi Model 131
4.3.2 Models with Anisotropic Vortices 133
4.4 The Vortex Path Model or Maximum Entropy Modeling 134
4.5 Conclusions 140
References 141
5 Vortex Avalanches in Superconductors Visualized by Magneto-Optical Imaging 143
5.1 Introduction 143
5.1.1 Flux Avalanche Phenomena in Superconductors: Historical Findings 144
5.1.2 Magneto-Optical Imaging with an “Indicator” 145
5.1.2.1 “Regular” Critical State Observed by MOI 146
5.2 Observations of Magnetic Flux Avalanches 147
5.2.1 Flux Jumps Observed in Bulk Superconductors 148
5.2.2 Vortex Avalanches in Superconducting Films 150
5.2.2.1 Vortex Avalanches in Metallic Superconductors 150
Finger and Dendritic Flux Pattern in Nb Films 150
Dendritic VAs in MgB2 152
Avalanches Observed in Other Metallic Superconductors 155
5.2.2.2 Vortex Avalanches in Cuprate Superconductors 156
5.3 Modeling Vortex Avalanches 160
5.3.1 Recent Models and Simulations 160
5.4 Summary and Perspectives 163
Acknowledgements 165
References 165
6 Behavior of the Second Magnetization Peak in Self-nanostructured La2–xSrxCuO4 Single Crystals 168
6.1 Introduction 168
6.2 Samples and Experiments 170
6.3 Analysis of the Second Magnetization Peak in Overdoped La2–xSrxCuO4 Single Crystals 171
6.4 Disappearance of the Second Magnetization Peak in the Presence of Static Stripe Order 178
6.5 The Ac Magnetic Response of Specimens Exhibiting a Second Magnetization Peak 184
6.6 Vortex Phase Diagram of La2–xSrxCuO4 Single Crystals 187
6.7 Conclusions 188
Acknowledgements 189
References 189
7 Emergence of an Interband Phase Difference and Its Consequences in Multiband Superconductors 194
7.1 Introduction 194
7.2 Quantum Phase of a Superconducting Wave Function and the Interband Phase Difference Soliton in Multiband Superconductors 197
7.3 The Mass of the Soliton and the Interband Interaction 202
7.4 Frustrated Superconductivity and the Massless Leggett Mode 203
7.5 Entropy and Another Superconducting Transition 207
7.6 Current-Induced Interband Phase Difference 210
7.7 Summary 218
Acknowledgements 219
References 219
8 Fluctuation Modes in Multi-gap Superconductors 228
8.1 Introduction 228
8.2 Gap Equation and an Analogy to the Particle Physics 230
8.2.1 BCS Theory 230
8.2.2 Nambu-Jona-Lasinio Model 233
8.3 Multi-gap Superconductivity 235
8.4 Effective Action of Multi-gap Superconductors 236
8.5 Nambu-Goldstone and Leggett Modes 238
8.5.1 Effective Action 238
8.5.2 Nambu-Goldstone-Leggett Mode for Neutral Superconductors 238
8.5.3 Plasma and Leggett Modes 239
8.6 Higgs Mode 242
8.6.1 Effective Action Near Tc 242
8.6.2 Effective Action at Low Temperature 243
8.7 Time-Reversal Symmetry Breaking 246
8.8 Half-Quantum Flux Vortex and a Monopole 248
8.9 Massless Nambu-Goldstone Modes 250
8.10 Sine-Gordon Model 252
8.10.1 (d+1)D Sine-Gordon Model 252
8.10.2 Renormalization Group Equation 252
8.11 Chiral Transition 254
8.11.1 N-variable Sine-Gordon Model 254
8.11.2 Chirality Transition 255
8.12 SU(N) Sine-Gordon Model 257
8.13 Summary 259
References 260
Author Index 263
Index 264

Produkt-Details

• Erscheint lt. Verlag: 19.7.2017
• Reihe/Serie: Springer Series in Materials Science
• Reihe/Serie: Springer Series in Materials Science
• Zusatzinfo: XIV, 259 p. 121 illus., 63 illus. in color.
• Verlagsort: Cham
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik ► Maschinenbau
• Schlagworte: Liquid Hydrogen Cryomagnetics • MgB2 Superconductors • Multicomponent Superconductivity • Multiharmonic AC Susceptibility • Nanostructured SWuperconductors book • Scanning Hall Probe Microscopy Vortices • Vortex Avalanches • Vortex Dynamics • Vortex Dynamics Current Anisotropy • Vortex Pinning Superconductivity • Vortex Ratchet Effects C
• ISBN-10: 3-319-59355-2 / 3319593552
• ISBN-13: 978-3-319-59355-5 / 9783319593555