Nanostructured Superconductors

Drawing from the broad spectrum of phenomena, described in more than 100,000 articles on high-Tc superconductivity, in this book, the authors analyze those basic properties for which understanding can be achieved within the framework of traditional methods of theoretical physics. This is the case of the overdoped cuprates for which the "Bardeen program" has been realized: We know their electronic spectrum, we can calculate their basic thermodynamic and electrodynamic properties, and predict new phenomena. The book gives a pedagogical derivation of formulas describing the electron band structure, penetration depth, specific heat, fluctuation conductivity, etc. Prediction of plasmons and their application for a new type of THz generators is considered as well. The book advocates that the strongest exchange interaction in condensed matter physics -- the intraatomic s-d exchange -- is the long sought pairing mechanism in overdoped cuprate superconductors The main focus of the book is to present the effects of nanostructuring on superconducting critical parameters. Optimizing systematically flux and condensate confinement in various nanostructured superconductors, ranging from single nano-cells to their huge arrays, critical fields and currents can be increased up to their theoretical limits, thus drastically improving the potential for practical applications of nanostructured superconductors. Read more... 1. Introduction. 1.1. Quantization and confinement in nano-materials. 1.2. Nanostructuring. 1.3. Confining the superconducting condensate. 1.4. Nucleation of superconductivity in presence of spatially modulated magnetic fields. 1.5. Vortex matter in superconductors. 1.6. Flux pinning -- 2. Individual nanostructures. 2.1. Line. 2.2. Loop. 2.3. Disc. 2.4. The cross-over from loop to dot. 2.5. Symmetry-induced antivortices in mesoscopic superconductors. 2.6. The magnetization of singly connected nanostructures. 2.7. Dynamic effects in mesoscopic structures. 2.8. Hybrid individual cells -- 3. Clusters of nanocells. 3.1. One-dimensional clusters of loops. 3.2. Two-dimensional clusters of antidots. 3.3. Magnetically coupled loops -- 4. Laterally nanostructured superconductors. 4.1. The T[symbol](H) phase boundary of superconducting films with an antidot lattice. 4.2. Pinning in laterally nanostructured superconductors. 4.3. Ratchet effects in antidot lattices -- 5. Superconductor-ferromagnet hybrid systems. 5.1. Field polarity dependent vortex pinning in laterally nanostructured S/F systems. 5.2. Field induced superconductivity. 5.3. Dipole-induced vortex ratchet effects. 5.4. Superconductivity in stray fields of magnetic domains Acknowledgments; Preface; Contents; List of Figures; 1. Introduction; 1.1 Quantization and confinement in nano-materials; 1.2 Nanostructuring; 1.3 Confining the superconducting condensate; 1.4 Nucleation of superconductivity in presence of spatially modulated magnetic fields; 1.5 Vortex matter in superconductors; 1.5.1 The structure of a single vortex; 1.5.2 The vortex lattice - general considerations; 1.5.3 Vortex lattices in thin films; 1.5.4 Vortex lattices in type-1.5 superconductors; 1.6 Flux pinning; 1.6.1 Structural pinning; 1.6.2 Magnetic pinning; 2. Individual Nanostructures 2.1 Line2.2 Loop; 2.3 Disc; 2.4 The cross-over from loop to dot; 2.5 Symmetry-induced antivortices in mesoscopic superconductors; 2.5.1 Square; 2.5.2 Triangle; 2.5.3 Rectangles; 2.6 The magnetization of singly connected nanostructures; 2.6.1 Disc; 2.6.2 Triangle; 2.6.3 Square; 2.7 Dynamic effects in mesoscopic structures; 2.7.1 Rectification effects in a triangle; 2.7.2 Reversal of the diode effect; 2.7.3 The diode effect in a disk; 2.7.4 Comparison with a theoretical model; 2.8 Hybrid individual cells; 2.8.1 Square with magnetic dot; 2.8.2 Phase shifter; 3. Clusters of Nanocells 3.1 One-dimensional clusters of loops3.2 Two-dimensional clusters of antidots; 3.3 Magnetically coupled loops; 4. Laterally Nanostructured Superconductors; 4.1 The Tc(H) phase boundary of superconducting films with an antidot lattice; 4.2 Pinning in laterally nanostructured superconductors; 4.2.1 Pinning by an antidot or a columnar defect; 4.2.2 Regular pinning arrays; 4.2.3 Regular pinning arrays with nS = 1; 4.2.4 Multiquanta vortex lattices (nS> 1); 4.2.5 Crossover from pinning arrays to networks (nS 1); 4.2.6 Composite antidot lattices; 4.3 Ratchet effects in antidot lattices 4.3.1 Vortex rectification in films with asymmetric pinning4.3.2 Controlled multiple reversals of a ratchet effect; 4.3.3 The origin of reversed vortex ratchet motion; 5. Superconductor-Ferromagnet Hybrid Systems; 5.1 Field polarity dependent vortex pinning in laterally nanostructured S/F systems; 5.1.1 Vortex pinning by magnetic dots; 5.1.2 Commensurate vortex domain formation; 5.2 Field induced superconductivity; 5.3 Dipole-induced vortex ratchet effects; 5.3.1 Generation of vortex-antivortex pairs; 5.3.2 Switching rectification properties 5.4 Superconductivity in stray fields of magnetic domains5.4.1 Domain superconductivity and domain-wall superconductivity; 5.4.2 Direct visualization of reverse-domain superconductivity; 5.4.3 Superconducting - normal-state junctions induced by stray magnetic fields; Concluding Remarks; Bibliography; Index