Nanostructured Superconductors

Contents......Page 12
Preface......Page 8
Acknowledgments......Page 10
List of Figures......Page 16
1. Introduction......Page 22
1.1 Quantization and confinement in nano-materials......Page 24
1.2 Nanostructuring......Page 25
1.3 Confining the superconducting condensate......Page 27
1.4 Nucleation of superconductivity in presence of spatially modulated magnetic fields......Page 32
1.5 Vortex matter in superconductors......Page 34
1.5.1 The structure of a single vortex......Page 39
1.5.2 The vortex lattice — general considerations......Page 42
1.5.4 Vortex lattices in type-1.5 superconductors......Page 45
1.6 Flux pinning......Page 53
1.6.2 Magnetic pinning......Page 54
2. Individual Nanostructures......Page 58
2.1 Line......Page 59
2.2 Loop......Page 60
2.3 Disc......Page 65
2.4 The cross-over from loop to dot......Page 71
2.5 Symmetry-induced antivortices in mesoscopic superconductors......Page 78
2.5.1 Square......Page 79
2.5.2 Triangle......Page 84
2.5.3 Rectangles......Page 90
2.6 The magnetization of singly connected nanostructures......Page 94
2.6.1 Disc......Page 96
2.6.2 Triangle......Page 101
2.6.3 Square......Page 103
2.7.1 Rectification effects in a triangle......Page 107
2.7.2 Reversal of the diode effect......Page 109
2.7.3 The diode effect in a disk......Page 113
2.7.4 Comparison with a theoretical model......Page 114
2.8 Hybrid individual cells......Page 118
2.8.1 Square with magnetic dot......Page 119
2.8.2 Phase shifter......Page 125
3.1 One-dimensional clusters of loops......Page 132
3.2 Two-dimensional clusters of antidots......Page 138
3.3 Magnetically coupled loops......Page 142
4.1 The Tc(H) phase boundary of superconducting films with an antidot lattice......Page 148
4.2 Pinning in laterally nanostructured superconductors......Page 157
4.2.1 Pinning by an antidot or a columnar defect......Page 158
4.2.3 Regular pinning arrays with nS = 1......Page 160
4.2.4 Multiquanta vortex lattices (nS > 1)......Page 177
4.2.5 Crossover from pinning arrays to networks (nS   1)......Page 191
4.2.6 Composite antidot lattices......Page 195
4.3.1 Vortex rectification in films with asymmetric pinning......Page 204
4.3.2 Controlled multiple reversals of a ratchet effect......Page 211
4.3.3 The origin of reversed vortex ratchet motion......Page 217
5. Superconductor–Ferromagnet Hybrid Systems......Page 224
5.1 Field polarity dependent vortex pinning in laterally nanostructured S/F systems......Page 225
5.1.1 Vortex pinning by magnetic dots......Page 227
5.1.2 Commensurate vortex domain formation......Page 236
5.2 Field induced superconductivity......Page 241
5.3 Dipole-induced vortex ratchet effects......Page 246
5.3.1 Generation of vortex-antivortex pairs......Page 247
5.3.2 Switching rectification properties......Page 252
5.4 Superconductivity in stray fields of magnetic domains......Page 256
5.4.1 Domain superconductivity and domain-wall superconductivity......Page 257
5.4.2 Direct visualization of reverse-domain superconductivity......Page 263
5.4.3 Superconducting – normal-state junctions induced by stray magnetic fields......Page 268
Concluding Remarks......Page 278
Bibliography......Page 282
Index......Page 316