Professor Werner Buckel (1920-2003) became a professor at the Technical University of Karlsruhe, Germany, in 1960 after receiving his PhD at the University of Erlangen. Except for three years which he spent establishing the Institute for Superconductivity at the Research Center in Jülich, Germany, he remained at the Technical University of Karlsruhe until his retirement in 1985. Among other honorary positions, Professor Buckel held the chair of the president of the German Physical Society and the European Physical Society and was a member of the Heidelberg Academy of the Sciences and the Leibnitz Society, Berlin. He died in February 2003. Professor Reinhold Kleiner, born 1962, studied general physics at the Technical University of Munich, and there received his PhD in 1992 with a thesis on intrinsic Josephson efects in high temperature superconductors. After spending two years at the University of California at Berkeley, he returned to become assistant professor at the University of Erlangen-Nürnberg, Germany. In 2000, Reinhold Kleiner accepted a position as a full professor for experimental solid-state physics at the physics institute of the University of Tübingen, Germany. His research interests include superconductivity and magnetism, with a focus on Josephson effects and superconducting quantum interferometry.

• Introduction 11 Fundamental Properties of Superconductors 111.1 The Vanishing of the Electrical Resistance 111.2 Ideal Diamagnetism, Flux Lines, and Flux Quantization 211.3 Flux Quantization in a Superconducting Ring 281.4 Superconductivity: A Macroscopic Quantum Phenomenon 311.5 Quantum Interference 431.5.1 Josephson Currents 441.5.2 Quantum Interference in a Magnetic Field 572 Superconducting Elements, Alloys, and Compounds 732.1 Conventional and Unconventional Superconductors 732.2 Superconducting Elements 762.3 Superconducting Alloys and Metallic Compounds 812.3.1 The b-Tungsten Structure 812.3.2 Magnesium Diboride 832.3.3 Metal-Hydrogen Systems 842.4 Fullerides 852.5 Chevrel Phases and Boron Carbides 872.6 Heavy-Fermion Superconductors 902.7 Natural and Artificial Layered Superconductors 912.8 The Superconducting Oxides 932.8.1 Cuprates 942.8.2 Bismuthates, Ruthenates, and Other Oxide Superconductors 1002.9 Organic Superconductors 1012.10 Superconductivity Due to the Field Effect 1043 Cooper Pairing 1113.1 Conventional Superconductivity 1113.1.1 Cooper Pairing by Means of Electron-Phonon Interaction 1113.1.2 The Superconducting State, Quasiparticles, and BCS Theory 1183.1.3 Experimental Confirmation of Fundamental Concepts About the Superconducting State 1233.1.3.1 The Isotope Effect 1233.1.3.2 The Energy Gap 1263.1.4 Special Properties of Conventional Superconductors 1423.1.4.1 Influence of Lattice Defects on Conventional Cooper Pairing 1423.1.4.2 Influence of Paramagnetic Ions on Conventional Cooper Pairing 1493.2 Unconventional Superconductivity 1553.2.1 General Aspects 1553.2.2 High-Temperature Superconductors 1613.2.3 Heavy Fermions, Ruthenates, and Other Unconventional Superconductors 1784 Thermodynamics and Thermal Properties of the Superconducting State 1894.1 General Aspects of Thermodynamics 1894.2 Specific Heat 1934.3 Thermal Conductivity 1974.4 Ginzburg-Landau Theory 2004.5 Characteristic Lengths of Ginzburg-Landau Theory 2044.6 Type-I Superconductors in a Magnetic Field 2094.6.1 Critical Field and Magnetization of Rod-Shaped Samples 2104.6.2 Thermodynamics of the Meissner State 2144.6.3 Critical Magnetic Field of Thin Films in a Field Parallel to the Surface 2184.6.4 The Intermediate State 2194.6.5 The Wall Energy 2244.6.6 Influence of Pressure on the Superconducting State 2274.7 Type-II Superconductors in a Magnetic Field 2324.7.1 Magnetization Curve and Critical Fields 2334.7.2 The Shubnikov Phase 2434.8 Fluctuations Above the Transition Temperature 2544.9 States Outside Thermodynamic Equilibrium 2595 Critical Currents in Type-I and Type-II Superconductors 2695.1 Limit of the Supercurrent Due to Pair Breaking 2695.2 Type-I Superconductors 2715.3 Type-II Superconductors 2775.3.1 Ideal Type-II Superconductor 2775.3.2 Hard Superconductors 2825.3.2.1 Pinning of Flux Lines 2825.3.2.2 Magnetization Curve of Hard Superconductors 2865.3.2.3 Critical Currents and Current-Voltage Characteristics 2956 Josephson Junctions and Their Properties 3056.1 Current Transport Across Interfaces in a Superconductor 3056.1.1 Superconductor-Insulator Interface 3056.1.2 Superconductor-Normal Conductor Interfaces 3126.2 The RCSJ Model 3196.3 Josephson Junctions Under Microwave Irradiation 3246.4 Vortices in Long Josephson Junctions 3276.5 Quantum Properties of Superconducting Tunnel Junctions 3396.5.1 Coulomb Blockade and Single-Electron Tunneling 3396.5.2 Flux Quanta and Macroscopic Quantum Coherence 3457 Applications of Superconductivity 3517.1 Superconducting Magnetic Coils 3527.1.1 General Aspects 3527.1.2 Superconducting Cables and Tapes 3537.1.3 Coil Protection 3627.2 Superconducting Permanent Magnets 3647.3 Applications of Superconducting Magnets 3677.3.1 Nuclear Magnetic Resonance 3677.3.2 Magnetic Resonance Imaging 3717.3.3 Particle Accelerators 3727.3.4 Nuclear Fusion 3747.3.5 Energy Storage Devices 3767.3.6 Motors and Generators 3777.3.7 Magnetic Separation 3787.3.8 Levitated Trains 3797.4 Superconductors for Power Transmission: Cables, Transformers, and Current-Limiting Devices 3807.4.1 Superconducting Cables 3817.4.2 Transformers 3837.4.3 Current-Limiting Devices 3837.5 Superconducting Resonators and Filters 3847.5.1 High-Frequency Behavior of Superconductors 3857.5.2 Resonators for Particle Accelerators 3887.5.3 Resonators and Filters for Communications Technology 3917.6 Superconducting Detectors 3967.6.1 Sensitivity, Thermal Noise, and Environmental Noise 3977.6.2 Incoherent Radiation and Particle Detection: Bolometers and Calorimeters 3987.6.3 Coherent Detection and Generation of Radiation: Mixers, Local Oscillators, and Integrated Receivers 4027.6.4 Quantum Interferometers as Magnetic Field Sensors 4097.6.4.1 SQUID Magnetometer: Basic Concepts 4097.6.4.2 Environmental Noise, Gradiometers, and Shielding 4207.6.4.3 Applications of SQUIDs 4237.7 Superconductors in Microelectronics 4277.7.1 Voltage Standards 4277.7.2 Digital Electronics Based on Josephson Junctions 431References 435Monographs and Collections 443Outlook 447Subject Index 453

Professor Werner Buckel (1920-2003) became a professor at the Technical University of Karlsruhe, Germany, in 1960 after receiving his PhD at the University of Erlangen. Except for three years which he spent establishing the Institute for Superconductivity at the Research Center in Jülich, Germany, he remained at the Technical University of Karlsruhe until his retirement in 1985. Among other honorary positions, Professor Buckel held the chair of the president of the German Physical Society and the European Physical Society and was a member of the Heidelberg Academy of the Sciences and the Leibnitz Society, Berlin. He died in February 2003. Professor Reinhold Kleiner, born 1962, studied general physics at the Technical University of Munich, and there received his PhD in 1992 with a thesis on intrinsic Josephson efects in high temperature superconductors. After spending two years at the University of California at Berkeley, he returned to become assistant professor at the University of Erlangen-Nürnberg, Germany. In 2000, Reinhold Kleiner accepted a position as a full professor for experimental solid-state physics at the physics institute of the University of Tübingen, Germany. His research interests include superconductivity and magnetism, with a focus on Josephson effects and superconducting quantum interferometry.

• Introduction 11 Fundamental Properties of Superconductors 111.1 The Vanishing of the Electrical Resistance 111.2 Ideal Diamagnetism, Flux Lines, and Flux Quantization 211.3 Flux Quantization in a Superconducting Ring 281.4 Superconductivity: A Macroscopic Quantum Phenomenon 311.5 Quantum Interference 431.5.1 Josephson Currents 441.5.2 Quantum Interference in a Magnetic Field 572 Superconducting Elements, Alloys, and Compounds 732.1 Conventional and Unconventional Superconductors 732.2 Superconducting Elements 762.3 Superconducting Alloys and Metallic Compounds 812.3.1 The b-Tungsten Structure 812.3.2 Magnesium Diboride 832.3.3 Metal-Hydrogen Systems 842.4 Fullerides 852.5 Chevrel Phases and Boron Carbides 872.6 Heavy-Fermion Superconductors 902.7 Natural and Artificial Layered Superconductors 912.8 The Superconducting Oxides 932.8.1 Cuprates 942.8.2 Bismuthates, Ruthenates, and Other Oxide Superconductors 1002.9 Organic Superconductors 1012.10 Superconductivity Due to the Field Effect 1043 Cooper Pairing 1113.1 Conventional Superconductivity 1113.1.1 Cooper Pairing by Means of Electron-Phonon Interaction 1113.1.2 The Superconducting State, Quasiparticles, and BCS Theory 1183.1.3 Experimental Confirmation of Fundamental Concepts About the Superconducting State 1233.1.3.1 The Isotope Effect 1233.1.3.2 The Energy Gap 1263.1.4 Special Properties of Conventional Superconductors 1423.1.4.1 Influence of Lattice Defects on Conventional Cooper Pairing 1423.1.4.2 Influence of Paramagnetic Ions on Conventional Cooper Pairing 1493.2 Unconventional Superconductivity 1553.2.1 General Aspects 1553.2.2 High-Temperature Superconductors 1613.2.3 Heavy Fermions, Ruthenates, and Other Unconventional Superconductors 1784 Thermodynamics and Thermal Properties of the Superconducting State 1894.1 General Aspects of Thermodynamics 1894.2 Specific Heat 1934.3 Thermal Conductivity 1974.4 Ginzburg-Landau Theory 2004.5 Characteristic Lengths of Ginzburg-Landau Theory 2044.6 Type-I Superconductors in a Magnetic Field 2094.6.1 Critical Field and Magnetization of Rod-Shaped Samples 2104.6.2 Thermodynamics of the Meissner State 2144.6.3 Critical Magnetic Field of Thin Films in a Field Parallel to the Surface 2184.6.4 The Intermediate State 2194.6.5 The Wall Energy 2244.6.6 Influence of Pressure on the Superconducting State 2274.7 Type-II Superconductors in a Magnetic Field 2324.7.1 Magnetization Curve and Critical Fields 2334.7.2 The Shubnikov Phase 2434.8 Fluctuations Above the Transition Temperature 2544.9 States Outside Thermodynamic Equilibrium 2595 Critical Currents in Type-I and Type-II Superconductors 2695.1 Limit of the Supercurrent Due to Pair Breaking 2695.2 Type-I Superconductors 2715.3 Type-II Superconductors 2775.3.1 Ideal Type-II Superconductor 2775.3.2 Hard Superconductors 2825.3.2.1 Pinning of Flux Lines 2825.3.2.2 Magnetization Curve of Hard Superconductors 2865.3.2.3 Critical Currents and Current-Voltage Characteristics 2956 Josephson Junctions and Their Properties 3056.1 Current Transport Across Interfaces in a Superconductor 3056.1.1 Superconductor-Insulator Interface 3056.1.2 Superconductor-Normal Conductor Interfaces 3126.2 The RCSJ Model 3196.3 Josephson Junctions Under Microwave Irradiation 3246.4 Vortices in Long Josephson Junctions 3276.5 Quantum Properties of Superconducting Tunnel Junctions 3396.5.1 Coulomb Blockade and Single-Electron Tunneling 3396.5.2 Flux Quanta and Macroscopic Quantum Coherence 3457 Applications of Superconductivity 3517.1 Superconducting Magnetic Coils 3527.1.1 General Aspects 3527.1.2 Superconducting Cables and Tapes 3537.1.3 Coil Protection 3627.2 Superconducting Permanent Magnets 3647.3 Applications of Superconducting Magnets 3677.3.1 Nuclear Magnetic Resonance 3677.3.2 Magnetic Resonance Imaging 3717.3.3 Particle Accelerators 3727.3.4 Nuclear Fusion 3747.3.5 Energy Storage Devices 3767.3.6 Motors and Generators 3777.3.7 Magnetic Separation 3787.3.8 Levitated Trains 3797.4 Superconductors for Power Transmission: Cables, Transformers, and Current-Limiting Devices 3807.4.1 Superconducting Cables 3817.4.2 Transformers 3837.4.3 Current-Limiting Devices 3837.5 Superconducting Resonators and Filters 3847.5.1 High-Frequency Behavior of Superconductors 3857.5.2 Resonators for Particle Accelerators 3887.5.3 Resonators and Filters for Communications Technology 3917.6 Superconducting Detectors 3967.6.1 Sensitivity, Thermal Noise, and Environmental Noise 3977.6.2 Incoherent Radiation and Particle Detection: Bolometers and Calorimeters 3987.6.3 Coherent Detection and Generation of Radiation: Mixers, Local Oscillators, and Integrated Receivers 4027.6.4 Quantum Interferometers as Magnetic Field Sensors 4097.6.4.1 SQUID Magnetometer: Basic Concepts 4097.6.4.2 Environmental Noise, Gradiometers, and Shielding 4207.6.4.3 Applications of SQUIDs 4237.7 Superconductors in Microelectronics 4277.7.1 Voltage Standards 4277.7.2 Digital Electronics Based on Josephson Junctions 431References 435Monographs and Collections 443Outlook 447Subject Index 453

Professor Werner Buckel (1920-2003) became a professor at the Technical University of Karlsruhe, Germany, in 1960 after receiving his PhD at the University of Erlangen. Except for three years which he spent establishing the Institute for Superconductivity at the Research Center in Jülich, Germany, he remained at the Technical University of Karlsruhe until his retirement in 1985. Among other honorary positions, Professor Buckel held the chair of the president of the German Physical Society and the European Physical Society and was a member of the Heidelberg Academy of the Sciences and the Leibnitz Society, Berlin. He died in February 2003. Professor Reinhold Kleiner, born 1962, studied general physics at the Technical University of Munich, and there received his PhD in 1992 with a thesis on intrinsic Josephson efects in high temperature superconductors. After spending two years at the University of California at Berkeley, he returned to become assistant professor at the University of Erlangen-Nürnberg, Germany. In 2000, Reinhold Kleiner accepted a position as a full professor for experimental solid-state physics at the physics institute of the University of Tübingen, Germany. His research interests include superconductivity and magnetism, with a focus on Josephson effects and superconducting quantum interferometry.

• Introduction 11 Fundamental Properties of Superconductors 111.1 The Vanishing of the Electrical Resistance 111.2 Ideal Diamagnetism, Flux Lines, and Flux Quantization 211.3 Flux Quantization in a Superconducting Ring 281.4 Superconductivity: A Macroscopic Quantum Phenomenon 311.5 Quantum Interference 431.5.1 Josephson Currents 441.5.2 Quantum Interference in a Magnetic Field 572 Superconducting Elements, Alloys, and Compounds 732.1 Conventional and Unconventional Superconductors 732.2 Superconducting Elements 762.3 Superconducting Alloys and Metallic Compounds 812.3.1 The b-Tungsten Structure 812.3.2 Magnesium Diboride 832.3.3 Metal-Hydrogen Systems 842.4 Fullerides 852.5 Chevrel Phases and Boron Carbides 872.6 Heavy-Fermion Superconductors 902.7 Natural and Artificial Layered Superconductors 912.8 The Superconducting Oxides 932.8.1 Cuprates 942.8.2 Bismuthates, Ruthenates, and Other Oxide Superconductors 1002.9 Organic Superconductors 1012.10 Superconductivity Due to the Field Effect 1043 Cooper Pairing 1113.1 Conventional Superconductivity 1113.1.1 Cooper Pairing by Means of Electron-Phonon Interaction 1113.1.2 The Superconducting State, Quasiparticles, and BCS Theory 1183.1.3 Experimental Confirmation of Fundamental Concepts About the Superconducting State 1233.1.3.1 The Isotope Effect 1233.1.3.2 The Energy Gap 1263.1.4 Special Properties of Conventional Superconductors 1423.1.4.1 Influence of Lattice Defects on Conventional Cooper Pairing 1423.1.4.2 Influence of Paramagnetic Ions on Conventional Cooper Pairing 1493.2 Unconventional Superconductivity 1553.2.1 General Aspects 1553.2.2 High-Temperature Superconductors 1613.2.3 Heavy Fermions, Ruthenates, and Other Unconventional Superconductors 1784 Thermodynamics and Thermal Properties of the Superconducting State 1894.1 General Aspects of Thermodynamics 1894.2 Specific Heat 1934.3 Thermal Conductivity 1974.4 Ginzburg-Landau Theory 2004.5 Characteristic Lengths of Ginzburg-Landau Theory 2044.6 Type-I Superconductors in a Magnetic Field 2094.6.1 Critical Field and Magnetization of Rod-Shaped Samples 2104.6.2 Thermodynamics of the Meissner State 2144.6.3 Critical Magnetic Field of Thin Films in a Field Parallel to the Surface 2184.6.4 The Intermediate State 2194.6.5 The Wall Energy 2244.6.6 Influence of Pressure on the Superconducting State 2274.7 Type-II Superconductors in a Magnetic Field 2324.7.1 Magnetization Curve and Critical Fields 2334.7.2 The Shubnikov Phase 2434.8 Fluctuations Above the Transition Temperature 2544.9 States Outside Thermodynamic Equilibrium 2595 Critical Currents in Type-I and Type-II Superconductors 2695.1 Limit of the Supercurrent Due to Pair Breaking 2695.2 Type-I Superconductors 2715.3 Type-II Superconductors 2775.3.1 Ideal Type-II Superconductor 2775.3.2 Hard Superconductors 2825.3.2.1 Pinning of Flux Lines 2825.3.2.2 Magnetization Curve of Hard Superconductors 2865.3.2.3 Critical Currents and Current-Voltage Characteristics 2956 Josephson Junctions and Their Properties 3056.1 Current Transport Across Interfaces in a Superconductor 3056.1.1 Superconductor-Insulator Interface 3056.1.2 Superconductor-Normal Conductor Interfaces 3126.2 The RCSJ Model 3196.3 Josephson Junctions Under Microwave Irradiation 3246.4 Vortices in Long Josephson Junctions 3276.5 Quantum Properties of Superconducting Tunnel Junctions 3396.5.1 Coulomb Blockade and Single-Electron Tunneling 3396.5.2 Flux Quanta and Macroscopic Quantum Coherence 3457 Applications of Superconductivity 3517.1 Superconducting Magnetic Coils 3527.1.1 General Aspects 3527.1.2 Superconducting Cables and Tapes 3537.1.3 Coil Protection 3627.2 Superconducting Permanent Magnets 3647.3 Applications of Superconducting Magnets 3677.3.1 Nuclear Magnetic Resonance 3677.3.2 Magnetic Resonance Imaging 3717.3.3 Particle Accelerators 3727.3.4 Nuclear Fusion 3747.3.5 Energy Storage Devices 3767.3.6 Motors and Generators 3777.3.7 Magnetic Separation 3787.3.8 Levitated Trains 3797.4 Superconductors for Power Transmission: Cables, Transformers, and Current-Limiting Devices 3807.4.1 Superconducting Cables 3817.4.2 Transformers 3837.4.3 Current-Limiting Devices 3837.5 Superconducting Resonators and Filters 3847.5.1 High-Frequency Behavior of Superconductors 3857.5.2 Resonators for Particle Accelerators 3887.5.3 Resonators and Filters for Communications Technology 3917.6 Superconducting Detectors 3967.6.1 Sensitivity, Thermal Noise, and Environmental Noise 3977.6.2 Incoherent Radiation and Particle Detection: Bolometers and Calorimeters 3987.6.3 Coherent Detection and Generation of Radiation: Mixers, Local Oscillators, and Integrated Receivers 4027.6.4 Quantum Interferometers as Magnetic Field Sensors 4097.6.4.1 SQUID Magnetometer: Basic Concepts 4097.6.4.2 Environmental Noise, Gradiometers, and Shielding 4207.6.4.3 Applications of SQUIDs 4237.7 Superconductors in Microelectronics 4277.7.1 Voltage Standards 4277.7.2 Digital Electronics Based on Josephson Junctions 431References 435Monographs and Collections 443Outlook 447Subject Index 453