Principles of Superconductive Devices and Circuits

by Van Duzer, Theodore; Turner, Charles W.

• ISBN13: 9780132627429
• ISBN10: 0132627426
• Edition: 2nd
• Format: Paperback
• Copyright: 1998-12-07
• Publisher: PEARSO
• More Book Details
• Purchase Benefits

Summary

Preface to the Second Edition
Several exciting major developments have changed the field of applied superconductivity since 1981, when the first edition of this text was published. New materials and fabrication methods and innovative device and circuit concepts have made profound changes in the way we practice in this field. The most public of the changes was the discovery in 1986 of high-temperature oxide superconductors, several of which quickly were shown to have transition temperatures above the boiling point of nitrogen. Equally important but less publicly obvious was a pair of key innovations in the fabrication of superconductive integrated circuits. A way of making high quality, durable niobium tunnel junctions and a procedure to avoid any processing steps intervening in the fabrication of the junctions, has led to stable, well controlled integrated circuits. New concepts in superconductive detectors and mixers has made superconductivity the technology of choice in millimeter wave radio astronomy. And in the digital field, innovative ideas for single flux quantum logic and for hybridization with semiconductor devices have brought new opportunities. To date, the high-temperature superconductors have had their major impacts in magnetometers and microwave receivers. The greatly reduced refrigerator burden when using these materials compared with the metal superconductors has stimulated very extensive research on making cables for extremely high field magnets, and optimism for use in power systems.

The basic theory of superconductivity we presented in the 1981 edition is still very useful. There is, as yet, no accepted theory of electron pairing in the high-temperature superconductors and much of the practical work, including that on high-temperature superconductors, still relies on the theories in this book. Phenomenological theories have been developed to explain the behavior of high-temperature superconductors. And the low-temperature metallic superconductors continue to be of major importance, not least because of the success of Nb-Ti alloy in MRI magnets, by far the largest commercial market for superconductors. The low-temperature superconductor wire technology has matured over the past two decades and continues to make impressive progress. On the other hand, the fast pace of development of the physics and technology of the high-temperature superconductors presents us with a difficult choice. We have chosen to present a practical view of the current position, but freely admit that new results in this rapidly changing field may lead to a complete reappraisal.

Between us two co-authors, we have had several decades of experience with applications of superconductivity, both in the university and in industry. We have attempted to infuse the presentations, particularly of the electronics part, with our practical views that we hope will be helpful to the readers.

We thank several colleagues in the field including John Clarke, James Lukens, V. K. Kaplunenko, William McGrath, Oleg Mukhanov, Paul Richards, Andrew Smith, Stephen Whiteley, Yongming Zhang, who were very helpful with suggestions on sections in their areas of special expertise and in providing valuable data. Feedback from numerous students over the years has helped to form the presentations.

The need to prepare camera-ready copy for this edition led to the involvement of a large number of people in the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley, to whom we are deeply grateful. We appreciate their generous giving of time and talent. Carol Sitea was responsible for a part of the typing, inserting scores of figures into the text and making corrections, managing the computer aspects of the project, and finally pulling the manuscript together. Thank you Carol! We appreciate that Joyce McDougal generously organized the staff and participated in the typing of several chapters. Invaluable was the volunteered help from Christine Colbert, Dianna Bolt, and Jay Ento, each of whom typed several chapters. Jennifer Basler's help is appreciated. George Chien played a key role in assembling and modifying some of the most changed chapters.

Important computations were carried out by Yiqun Phillip Xie and Lizhen Zheng and Mark Jeffery provided valuable assistance. The artistic and computer talents of Katherina Law came together to create close to one hundred new figures, matching them in style to those of the first edition. The willing help of Luis Vasquez in carefully scanning hundreds of figures from the first edition and doing extensive library research were essential to the timely completion of the project, and greatly appreciated. Even our wives, Janice and Shan, volunteered help in proofreading and other ways; how can we thank them enough? Getting this edition into camera-ready form has truly been a community project and we are thankful to all who had a role.

T. Van Duzer, Berkeley
C. W. Turner, London

Table of Contents

Preface to the Second Edition	ix	(2)
Preface to the First Edition	xi
Chapter 1 Normal Metals and the Transition to the Superconducting State	1	(38)
1.01 Introduction	1	(1)
1.02 Independent Electrons in a Periodic Lattice	2	(4)
1.03 Energy Distribution and the Fermi Surface	6	(2)
1.04 Free-Electron Gas	8	(3)
1.05 Excitations: The Energy Gap in a Superconductor	11	(3)
1.06 Electronic Heat Capacity	14	(3)
1.07 The Phonon Spectrum	17	(6)
1.08 Scattering of Electrons by Phonons	23	(3)
1.09 Electrical Conductivity and Resistivity: The Superconducting State	26	(5)
1.10 Collisionless Conductor vs. Superconductor: The Meissner Experiment	31	(4)
1.11 Superconducting Materials	35	(4)
Chapter 2 Microscopic Theory of the Equilibrium Superconducting State and Single-Particle Tunneling	39	(53)
2.01 Introduction	39	(2)
2.02 Electron Pairing	41	(4)
2.03 The Cooper Pair Model	45	(5)
2.04 Dielectric Functions and Scattering Amplitudes	50	(2)
2.05 Attractive Electron-Electron Interaction	52	(5)
2.06 Hamiltonian for the Superconducting Ground State	57	(2)
2.07 Superconducting Ground State	59	(3)
2.08 Gap Parameter and Condensation Energy at T = 0	62	(3)
2.09 Excitations from the Ground State	65	(3)
2.10 Occupation Statistics for Pairs and Excitations for T is not equal to 0	68	(2)
2.11 Temperature Dependence of the Gap Parameter	70	(2)
2.12 Density of Excitation States	72	(4)
2.13 Tunneling Barriers	76	(2)
2.14 Tunneling Between Normal Metals	78	(5)
2.15 Tunneling Between a Normal Metal and a Superconductor	83	(5)
2.16 Quasiparticle Tunneling Between Superconductors	88	(4)
Chapter 3 Electrodynamics of Superconductors in Weak Magnetic Fields	92	(66)
3.01 Introduction	92	(2)
3.02 Current-Field Relations	94	(1)
3.03 Boson-Gas Model: London Equations	94	(3)
3.04 Gauge Transformation	97	(1)
3.05 Gauge Selection for Simply Connected Superconductors: The London Gauge	98	(1)
3.06 dc Electrodynamic Solutions for Superconductors: The Meissner Effect and Penetration Depth	99	(4)
3.07 Two-Dimensional Transition Between a Normal Conductor and a Superconductor	103	(3)
3.08 Isolated Current-Carrying Thin Strip	106	(4)
3.09 Inductance of Thin Film Lines	110	(6)
3.10 Quantization of Magnetic Flux in a Superconducting Ring	116	(2)
3.11 Nonlocal Field-Current Relation: Pippard Coherence Length	118	(3)
3.12 Penetration Depths for Pure and Impure Materials at T = 0	121	(3)
3.13 Temperature Dependences of Carrier Densities and Penetration Depths: The Two-Fluid Model	124	(1)
3.14 Complex Conductivity	125	(4)
3.15 Electromagnetic Fields in Conducting Media	129	(8)
3.16 Superconducting Transmission Lines	137	(8)
3.17 Superconducting Passive Microwave Components	145	(13)
Chapter 4 Josephson Junctions	158	(60)
4.01 Introduction	158	(1)
4.02 Pair Tunneling: The Josephson Relations	159	(5)
4.03 Gauge Invariance: Effect of a Magnetic Field	164	(3)
4.04 Wave Equation for a Josephson Tunnel Junction	167	(4)
4.05 Dependence of Maximum Zero-Voltage Current on Magnetic Field	171	(8)
4.06 Self-Field Effects: Dependence of I(c) on Shape and Size of Junction	179	(6)
4.07 Resonances in Josephson Junctions: Fiske Modes	185	(2)
4.08 Conducting-Barrier Josephson Junctions	187	(5)
4.09 Circuit Models of Josephson Junctions	192	(4)
4.10 Static I-V Characteristics with a dc Source	196	(5)
4.11 Analogs of Small-Area Josephson Junctions	201	(5)
4.12 RF Effects in Josephson Junctions	206	(7)
4.13 Fluctuations (Noise) in Josephson Junctions	213	(5)
Chapter 5 Electronics Applications	218	(108)
5.01 Introduction	218	(1)
5.02 Josephson Direct Detection and Mixing	219	(8)
5.03 Quasiparticle Detection and Mixing in SIS Junctions	227	(6)
5.04 Bolometric Detectors and Mixers	233	(7)
5.05 Parametric Interactions	240	(3)
5.06 RF Signal Generation in Junction Arrays	243	(5)
5.07 Oscillators Based on Fluxon Dynamics in Long Junctions	248	(4)
5.08 Josephson Volt Standard	252	(4)
5.09 One-Junction SQUID	256	(4)
5.10 Multi-Junction SQUIDs	260	(11)
5.11 dc SQUID Magnetometers	271	(9)
5.12 RF SQUID Magnetometers	280	(3)
5.13 Components for Josephson Digital Circuits	283	(7)
5.14 Voltage-State Logic	290	(9)
5.15 Single-Flux-Quantum Digital Circuits	299	(6)
5.16 Rapid Single Flux Quantum (RSFQ) Logic	305	(7)
5.17 Digital Interface Circuits	312	(7)
5.18 Memories in Josephson and Hybrid Technologies	319	(7)
Chapter 6 Fundamental Thermodynamic and Magnetic Considerations	326	(30)
6.01 Introduction	326	(1)
6.02 Fundamental Concepts in Statistical Thermodynamics	326	(2)
6.03 Interacting Systems	328	(5)
6.04 Helmholtz and Gibbs Free Energies	333	(3)
6.05 Magnetization	336	(5)
6.06 Demagnetization Factors	341	(3)
6.07 Energy in Magnetic Fields	344	(2)
6.08 Thermodynamic Relations for Magnetic Systems	346	(3)
6.09 Phase Transitions	349	(3)
6.10 The Superconducting-Normal Phase Transition	352	(4)
Chapter 7 Spatially Dependent Behavior: Ginzburg-Landau Equations Departures from Meissner State	356	(27)
7.01 Introduction	356	(1)
7.02 Ginzburg-Landau Free-Energy Functional	357	(4)
7.03 Ginzburg-Landau Differential Equations	361	(2)
7.04 Examples of Solutions of the Ginzburg-Landau Equations; The Ginzburg-Landau Parameters	363	(5)
7.05 Gor'kov's Microscopic Justification for the Ginzburg-Landau Theory	368	(3)
7.06 Surface Energy at the Boundary Between Normal and Superconducting Phases in a Homogeneous Medium	371	(4)
7.07 Intrinsic Magnetic Behavior of Superconductors	375	(2)
7.08 Geometrical Effects: The Intermediate State	377	(2)
7.09 Proximity Effects: Contiguous Normal and Superconductive Materials	379	(4)
Chapter 8 Type II Superconductivity: Theory and Technology	383	(54)
8.01 Introduction	383	(2)
8.02 Mixed State in Type II Superconductors: The Vortex	385	(2)
8.03 London Model of the Mixed State	387	(2)
8.04 Behavior Near H(c1)	389	(2)
8.05 Magnetic Flux Configuration in the Mixed State: The Vortex Lattice	391	(5)
8.06 Behavior Near H(c2) and Surface Superconductivity in LTS Materials	396	(3)
8.07 Flux Penetration in Thin Films: Critical Fields in LTS Materials	399	(9)
8.08 Vortex Motion and Flux-Flow Resistance	408	(5)
8.09 Thermally Activated Flux Motion: Flux Creep and Flux Jumps	413	(5)
8.10 The Critical-State Model for Hard Superconductors	418	(5)
8.11 The Surface Barrier to Flux Entry	423	(3)
8.12 Stabilization of Superconducting Cables by the Use of Composite LTS Conductors	426	(7)
8.13 ac Losses at Power Frequencies	433	(4)
Appendix A Elements of Electron Tunneling	437	(4)
Appendix B Determination of Materials Parameters N(0), v(F), Xi(0), and Lambda(L) (0) from Experimental Data	441	(2)
Appendix C Computer-Aided-Design Tools	443	(2)
Subject Index	445	(7)
Author Index	452

Excerpts

Preface to the Second Edition Several exciting major developments have changed the field of applied superconductivity since 1981, when the first edition of this text was published. New materials and fabrication methods and innovative device and circuit concepts have made profound changes in the way we practice in this field. The most public of the changes was the discovery in 1986 of high-temperature oxide superconductors, several of which quickly were shown to have transition temperatures above the boiling point of nitrogen. Equally important but less publicly obvious was a pair of key innovations in the fabrication of superconductive integrated circuits. A way of making high quality, durable niobium tunnel junctions and a procedure to avoid any processing steps intervening in the fabrication of the junctions, has led to stable, well controlled integrated circuits. New concepts in superconductive detectors and mixers has made superconductivity the technology of choice in millimeter wave radio astronomy. And in the digital field, innovative ideas for single flux quantum logic and for hybridization with semiconductor devices have brought new opportunities. To date, the high-temperature superconductors have had their major impacts in magnetometers and microwave receivers. The greatly reduced refrigerator burden when using these materials compared with the metal superconductors has stimulated very extensive research on making cables for extremely high field magnets, and optimism for use in power systems. The basic theory of superconductivity we presented in the 1981 edition is still very useful. There is, as yet, no accepted theory of electron pairing in the high-temperature superconductors and much of the practical work, including that on high-temperature superconductors, still relies on the theories in this book. Phenomenological theories have been developed to explain the behavior of high-temperature superconductors. And the low-temperature metallic superconductors continue to be of major importance, not least because of the success of Nb-Ti alloy in MRI magnets, by far the largest commercial market for superconductors. The low-temperature superconductor wire technology has matured over the past two decades and continues to make impressive progress. On the other hand, the fast pace of development of the physics and technology of the high-temperature superconductors presents us with a difficult choice. We have chosen to present a practical view of the current position, but freely admit that new results in this rapidly changing field may lead to a complete reappraisal. Between us two co-authors, we have had several decades of experience with applications of superconductivity, both in the university and in industry. We have attempted to infuse the presentations, particularly of the electronics part, with our practical views that we hope will be helpful to the readers. We thank several colleagues in the field including John Clarke, James Lukens, V. K. Kaplunenko, William McGrath, Oleg Mukhanov, Paul Richards, Andrew Smith, Stephen Whiteley, Yongming Zhang, who were very helpful with suggestions on sections in their areas of special expertise and in providing valuable data. Feedback from numerous students over the years has helped to form the presentations. The need to prepare camera-ready copy for this edition led to the involvement of a large number of people in the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley, to whom we are deeply grateful. We appreciate their generous giving of time and talent. Carol Sitea was responsible for a part of the typing, inserting scores of figures into the text and making corrections, managing the computer aspects of the project, and finally pulling the manuscript together. Thank you Carol! We appreciate that Joyce McDougal generously organized the staff and participated in the typing of several chapt