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Superconductor Materials Science Metallurgy, Fabrication, and Applications
NATO ADVANCED STUDY INSTITUTES SERIES
A series of edited volumes comprising multifaceted studies of contemporary scientific issues by some of the best scientific minds in the world, assembled in cooperation with NATO Scientific Affairs Division.
Series B. Physics
Recent Volumes in this Series
Volume 65 - Nonequilibrium Superconductivity, Phonons, and Kapitza Boundaries edited by Kenneth E. Gray
Volume 66 - Techniques and Concepts of High-Energy Physics edited by Thomas Ferbel
Volume 67- Nuclear Structure edited by K. Abrahams, K. Allaart, and A. E. L. Dieperink
Volume 68 - Superconductor Materials Science: Metallurgy, Fabrication, and Applications edited by Simon Foner and Brian B. Schwartz
Volume 69 - Photovoltaic and Photoelectrochemical Solar Energy Conversion Edited by F. Cardon, W. P. Gomes, and W. Dekeyser
Volume 70 - Current Topics in Elementary Particle Physics edited by K. H. Mutter and K. Schilling
Volume 71 - Atomic and Molecular Collision Theory edited by Franco A. Gianturco
Volume 72 - Phase Transitions: Cargese 1980 edited by Maurice Levy, Jean-Claude Le GuiJIou, and Jean Zinn-Justin
Volume 73 - Scattering Techniques Applied to Supra molecular and Nonequilibrium Systems edited by Sow-Hsin Chen, Benjamin Chu, and Ralph Nossal
Volume 74 - Rigorous Atomic and Molecular Physics edited by G. Velo and A. S. Wightman
This series is published by an international board of publishers in conjunction with NATO Scientific Affairs Division
A Life Sciences Plenum Publishing Corporation B Physics London and New York
C Mathematical and Physical Sciences
D Behavioral and Social Sciences
E Applied Sciences
D. Reidel Publishing Company Dordrecht, Boston, and London
Sijthoff & Noordhoff International Publishers Alphen aan den Rijn, The Netherlands, and Germantown, U.S.A.
Superconductor Materials Science Metallurgy, Fabrication, and Applications
Edited by
Simon Foner Francis Bitter National Magnet Laboratory and Plasma Fusion Center, M.l. T. Cambridge, Massachusetts
and
Brian B. Schwartz Department of Physics Brooklyn College of The City University of New York Brooklyn, New York
and
Francis Bitter National Magnet Laboratory and Plasma Fusion Center, M.l. T. Cambridge, Massachusetts
PLENUM PRESS • NEW YORK AND LONDON Published in cooperation with NATO Scientific Affairs Division
Library of Congress Cataloging in Publication Data
Main entry under title:
Superconductor materials science: metallurgy, fabriCation, and applications (NATO advanced study institutes series. B-Physics; v. 68) Includes bibliographical references and index. 1. Superconductors. 2. Superconductors-Manufacture. I. Foner, Simon. ll. Schwartz,
Brian B., 1938- . III. Series: NATO advanced study institutes series. Series B, Physics; v. 68. TK454.4.S93M37 621.39 ISBN 978-1-4757-0039-8 ISBN 978-1-4757-0037-4 (eBook) DOl 10.1007/978-1-4757-0037-4
The Francis Bitter National Magnet Laboratory is sponsored by the National Science Foundation.
Fusion Research at the Plasma Fusion Center is sponsored by the Department of Energy.
Proceedings of a NATO Advanced Study Institute on the Science and Technology of Superconducting Materials, held August 20 - 30, 1980, in Sintra, Portugal
© 1981 Plenum Press, New York Softcover reprint of the hardcover 1st edition 1981 A Division of Plenum Publishing Corporation 233 Spring Street, New York, N.Y. 10013
All rights reserved
81-8669 AACR2
No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher
PREFACE
This book encompasses the science, measurement, fabrication, and use of superconducting materials in large scale and small scale technologies. The present book is in some sense a continuation and completion of a series of two earlier books based on NA TO Advanced Study Institutes held over the last decade. The first book in the series entitled Superconducting Machines ~nd Devices: Large Systems Applications edited by S. Foner and B. B. Schwartz (1974) represented a compilation of all the applications of superconducting technology. The second book entitled Superconductor Applications: Squids and Machines, edited by B. B. Schwartz and S. Foner (1977) reviewed small scale applications and up-dated the large scale applications of superconductivity at that time. These two books are both introductions and advanced reference volumes for almost all aspects of the applications of superconductivity. The growth of applied superconductivity has mushroomed in the decade of the 1970's. Technologies which were discussed in the beginning of the 1970's are now beyond the prototype stage.
Materials development and performance in operating systems is the basis of the continued applications and economic viability of superconducting technology. In this book, a complete review of all materials technology is presented by leading authorities who were instrumental in the development of superconducting materials technology.
The present book is based on the NATO Advanced Study
vi PREFACE
Institute entitled Superconducting Materials: Science and Technology which was held from August 20 to August 30, 1980 in Sintra, Portugal. Thus this Institute complements the two previous Advanced Study Institutes held in 1973 on Large Scale Superco,nducting Devices and in 1976 on Small Scale Superconducting Devices. As with the previous Institutes, the focus of the lectures involves both science and applications, but they concentrate on materials aspects. The first part of the book reviews the basic principles, properties and fabrication technology of practical materials including A15 materials, niobium-titanium alloys, and others. Following these chapters, a description of phase diagrams and mechanical properties of superconductors is discussed. Novel new techniques for fabrication of materials such as in situ and powder metallurgy techniques are reviewed. The practical fabrication technology, usually not covered in typical material articles, receives extensive coverage. In addition, amorphous materials and materials development for small scale devices such as Josephson junctions and SQUID devices are reviewed. A brief review of large scale applications of superconductivity is also presented. As with our previous books we also present reviews of national efforts in the U.S., Europe, Middle Europe, Japan, Canada and China. The three books, published as a result of the NATO Advanced Study Institutes in our view represent a very thorough reference to the science and technology of all aspects of applied superconductivity. These books represent an excellent starting point for any scientist or engineer interested in this new and rapidly growing technology.
The 1980 NATO Institute which resulted in the present volume involves planning which dates back to the 1973 and 1976 NATO Institutes. For the 1980 Institute we were very fortunate in having a very effective International Advisory Committee which helped us with the planning. This Committee included G. Bogner, Siemens AG,Germany, E.A. Edelsack, Office of Naval Research, Arlington, VA, USA, C. Rizzuto, Universita di Genova, Italy, M. Suenaga, Brookhaven National Laboratory, New York, NY, USA, and M. Wilson, Science Research Council, Oxfordshire, England. The detailed planning of the Institute was concurrent with the award of a development program on superconducting materials at the Francis Bitter National Magnet Laboratory and Plasma Fusion Center from the Department of Energy. We would especially like to thank Dr. E. E. Kintner, Director of the Plasma Fusion Branch of the U.S. Department of Energy as well as Professor R. Davidson, Director of the Plasma Fusion Center at MIT, and Dr. P. M. Stone, Dr. M. D. Johnson, Dr. D. H. Priester, Dr. O. Manley, and Dr. J. M. Turner of the U. S. Department of Energy. We wish to thank Dr. M. di Lullo of the NATO Scientific Affairs Division, for his continued interest and encouragement, and the NA TO Science Council for support of this Advanced Study Institute. We
PREFACE
also wish to thank the National Science Foundation for travel grants to 2 students. In addition, assistance was given to the Institute by the Francis Bitter National Magnet Laboratory and Plasma Fusion Center, MIT and Brooklyn College of the City University of New York. The continued support of Professor Benjamin Lax, Director of the National Magnet Laboratory and President R. L. Hess of Brooklyn College is appreciated.
vii
In addition to the lecturers, the NATO Institute had approximately 80 participants from 20 countries. Professor Luis Alcacer was the Local Chairman. He and his assistants at the University of Lisbon and other local institutions including the Laboratorio Nacional de Engenharia e Tecnologia Industrial, LNETI gave continuous help to all aspects of planning and operation of the Institute. We wish to thank Professor Alcacer and his wife Inez for help in choosing the site of the Institute in Sintra, and for their invaluable assistance with many phases of the Institute in Sintra. We would like to thank the people and officials of Sintra as well as Lisbon municipalities for their very generous hospitality of our Institute and its participants. In particular, we would like to thank the Governor of Lisbon, Dr. Neiva Correia and the Mayor of Sintra, Mr. Jose Lopes da Costa and other City Council members, especially the Brigadeiro Machado de Sousa for his help with the Institute and help with the hotel construction schedule. We would also like to thank the director of the hotel, Mr. Cardoso.
We received excellent cooperation from all the lecturers, and would like to thank them for their excellent talks, the prompt completion of their manuscripts, and cooperation in meeting the strict deadlines allowing us to maintain a very tight publication schedule. We would also like to thank Delphine Radclif for helping with the typingofthemanuBcripts as well as Jane Ecker and Mary Filoso. Brian Schwartz would like to thank his office staff including Gertrude Shaleesh, Goldie Waxman and Ethel Rothwax for their help in the many aspects of the Institute.
Simon Foner Cambridge, Massachusetts
and Brian B. Schwartz Brooklyn, New York
March 1981
The NATO Advanced Study Institute was fortunate in having Professor Bernd Matthias participate actively in all phases of the Institute including preparing a joint paper with Dr. John Hu1m. As usual Bernd presented enthusiastic and provocative lectures and contributed actively to the discussions. His paper is the leadoff article in this book on Superconducting Materials. It is with great regret that we acknowledge that Bernd Matthias died suddenly in late October, about 2 months after the NATO Institute. The community has expressed its sorrow and a deep sense of loss of Berndts active and creative contributions to the development of superconducting materials. The authors share this sorrow, and hope this book with its leadoff article coauthored by Professor Matthias, will serve as an inspiration for continued development in the advancement of the science and technology of superconducting materials.
Simon Foner Cambridge, Mas sachusetts
and Brian B. Schwartz Brooklyn, New York
March 1981
ix
CONTENTS
CHAPTER 1 OVERVIEW OF SUPERCONDUCTING MATERIALS DEVELOPMENT
I.
II.
III.
IV.
V.
J. K. Hulm and B. T. Matthias
INTRODUCTION
SUPERCONDUCTING MATERIALS OF THE FIRST KIND
A. B. C. D.
E. F.
Discovery Magnetic Properties Flux Penetration Nature of the Superconducting Transition 1. Bulk phase transition 2. Thin film phase transition The Two Fluid Model The Microscopic Theory
SUPERCONDUCTING ALLOYS AND COMPOUNDS, EARLY WORK
A. B. C.
Introduction Critical Temperature Behavior Magnetic Field Behavior
RAISING T WITH NEW MATERIALS c
A. B. C. D.
Introduction Transition Metal Alloys Carbides and Nitrides' A15 Compounds 1. Progress in raising T 2. Present T situation c 3. Factors d~pressing T 4. Other features of Al§ behavior
SUPERCONDUCTORS OF THE SECOND KIND
xi
1
3
3 3 8 9
11 11 13 14
16
16 18 21
27
27 30 35 37 37 39 41 43
44
xii
VI.
A. B. C.
Introduction Another Kind of Superconductor Type II Materials
UNUSUAL MATERIALS AND FUTURE POSSIBILITIES
A. B. C. D. E. F.
Introduction Intercalation Compounds Organic Superconductors Low Carrier Density Superconductors Magnetic Superconductors Future Possibilities
CHAPTER 2 PRACTICAL SUPERCONDUCTING MATERIALS M.N. Wilson
I. INTRODUCTION
A. Practical Applications of Superconducting Materials
B. Superconducting Materials in Common Use C. Problems in the Utilization
of Superconducting Materials
II. STABILITY: THE GENERAL PROBLEM
A. Degradation and Training B. The Disturbance Spectrum C. Mechanical Sources of Disturbance D. Distributed Disturbances E. Point Disturbances F. Composite Conductors
III. FLUX JUMPING
A. General B. Screening Currents and the
Critical State Model C. Adiabatic Theory of Flux Jumping D. Filamentary Composites E. Dynamic Stability F. Dynamic Stability with Finite
Superconductor Thickness
IV. CRYOGENIC STABILIZATION
A. Size Effects B. Principles of Cryogenic Stabilization
CONTENTS
44 47 50
53
53 54 56 56 57 57
63
63 65
67
68
68 69 70 71 71 73
74
74
74 76 78 82
84
87
87 88
CONTENTS xiii
V.
VI.
VII.
C. D. E. F. G. H. I.
AC LOSSES
Boiling Heat Transfer Resistivity of the Normal Metal Heat Conduction Effects Effect of Finite Superconductor Size Forced Flow Cooling Superfluid Helium Cryogenic Stabilization in Practice
90 90 92 95 96
100 100
102
A. The Fundamental Loss Mechanism 102 B. Hysteresis Loss 104 C. Hysteresis Loss with Transport Current 108 D. Filamentary Composites 110 E. Self-Field Losses in Filamentary Composites 114 F. Longitudinal Field Effects 116 G. Combined Losses 119
QUENCHING AND PROTECTION
A. B. C. D. E.
The General Problem Temperature Rise Voltage Self-Protecting Magnets Other Protection Techniques
MEASUREMENT TECHNIQUES
A. B. C. D.
General Measurement of Critical Transport Current Measurement of Magnetization Measurement at Different Temperatures
119
119 120 122 122 123
124
124 124 127 130
CHAPTER 3 NIOBIUM-TITANIUM SUPERCONDUCTING MATERIALS
D.C. Larbalestier
I. INTRODUCT ION 133
II. METALLURGICAL AND STRUCTURAL PROPERTIES 134
A. Phases of the Niobium-Titanium System 136 B. Cold-Worked Microstructures 139 C. Elastic and Plastic Mechanical Behavior 152 D. Metallurgical Properties of Related Systems 157
III . PHYSICAL PROPERTIES 159
IV. SUPERCONDUCTING PROPERTIES 162
xiv
A. Basic Properties 1. Transition temperature
and upper critical field 2. Paramagnetic limitation
and spin-orbit scattering 3. Nb-Ti base ternary and quaternary
systems B~ The Superconducting Critical Current
Density 1. Measurement techniques 2. Critical current densities
V. INDUSTRIAL AND FABRICATION CONSIDERATIONS
VI. FUTURE DEVELOPMENTS AND NEW DIRECTIONS
A. Conventional Composites B. Unconventional Developments
CHAPTER 4 METALLURGY OF CONTINUOUS FILAMENTARY A15 SUPERCONDUCTORS
M. Suenaga
I.
u.
INTRODUCTION
HISTORY OF THE "BRONZE PROCESS"
A. B.
Early History Evolution of the Process 1. The Ta diffusion barrier 2. The external diffusion process 3. The internal tin diffusion process 4. Bronze in Nb tubing 5. WRAP process 6. Other modifications
III. METALLURGICAL PRINCIPLES
IV.
A. B.
Thermodynamic Considerations Kinetics 1. Growth mechanisms 2. Experimental results
INFLUENCE OF METALLURGICAL FACTORS ON SUPERCONDUCTING PROPERTIES
A. Strains in Composite Superconductors and
CONTENTS
162
162
163
167
173 173 174
187
190
190 192
201
202
202 204 204 205 206 208 208 209
209
209 215 215 221
233
Their Influence on the Superconducting Properties 234
CONTENTS xv
B. Critical Temperatures 238 1. Effects of heat treatments 238 2. Effects of additives 242
C. Critical-Current Densities and Magnetic Fields 246
1. Flux pinning (the scaling law) 246 2. Temperature dependence 256 3. Grain size dependence 258 4. Effects of heat treatments and alloying 261 5. What is required for high J c? 266
v. FUTURE DIRECTIONS 268
CHAPTER 5 FABRICATION TECHNOLOGY
I.
II.
OF SUPERCONDUCTING MATERIAL H. Hillmann
INTRODUCTION 275
TECHNOLOGY OF SOLID SOLUTION SUPERCONDUCTORS 276
A. B.
C. D.
Basic Properties of NbTi Alloys The influence of thermal treatment
in the region of 873 K Mechanical Properties of NbTi Alloys Stress-Strain Behavior at Elevated
276
285 288
Temperatures 292 E. Raw Materials and Melting of NbTi 292 F. Melting NbTi Alloys 292 G. Sources of Inhomogeneities and Imperfections
in the Mol ten Ingots 295 H. Conductors and Fabrication Parameters 299 I. Extrusion Technology 302
1. Extrusion billets and sealing techniques for single and multiextrusion 302
2. Extrusion presses and extrusion parameters 304
3. Extrusion temperature and preheating 311 4. Extrusion ram speed 311 5. Conductors containing mixed substrate 313
J. Drawing Machinery, Twisting and Current Optimization 313
K. Current Density Optimization and Properties of Monolithic Filamentary Conductors 317
L. The Anisotropy of Rectangularly-Shaped Conductors 323
M. Occurrence of the Ti 2Cu-Phase 328
xvi
III.
IV.
V.
CONTENTS
A15 SOLID SOLUTION CONDUCTORS 333
A. Basic Properties of Nb3Sn and V3Ga 333 B. Principles of Solid State Diffusion 337 C. Fabrication of the Conductors and
Technology of High Sn-Content Bronzes 340 D. Conductor Optimization with Respect to Layer
Growth, Recrystalization, Kirkendall Effect, Filament Diameter and Filament Distribution 345
E. Influence of Mechanical Strain on Electrical Properties 350
F. Remarks About the Measurement of Critical Current Density of Technical Conductors 360
G. Stabilization and Examples of Technical Conductors 362
CONDUCTOR ASSEMBLY BY BRAIDING, CABLING, MECHANICAL STRENGTHENING AND ADDING STABILIZERS
A.
B.
C.
Technical Production of Flattened Cables and Braids
Hollow Conductors and Fabrication Principles
Fabrication of High Current, High Strength Hollow Conductors
1. Strands 2. Cr-Ni core with Kapton insulation 3. Cabling and Soldering 4. Strip for the conduit 5. Conductor completion
FUTURE DIRECTIONS
A. B.
Solid Solution Superconductors A15 Superconductors
364
364
368
375 379 379 379 379 379
381
381 383
CHAPTER 6 ALTERNATIVE FABRICATION TECHNOLOGIES FOR A15 MULTIFILAMENTARY SUPERCONDUCTORS
R. Roberge
1. INTRODUCTION 389
II. CONVENTIONAL PROCESS MECHANICAL ASSEMBLY 390
A. Historical Note 390
CONTENTS xvii
III.
IV.
B. C. D.
Nb3Sn Technology Status Need for Alternate Technologies
390 393 394
IN SITU SOLIDIFICATION 394
A. Introduction 394 B. The Natural Dispersion of the Superconductor 395
1. Phase diagram, solidification process 395 * 2. Melting and casting techniques 399 C. Transformation into a Filamentary
Superconductor 404 1. Mechanical deformation 404 2. Tin addition 404 3. Diffusion and reaction heat-treatment 407
D. Superconducting Properties 411 1. Overall J c of Cu-Nb 411 2. Overall Jc of Cu-Sn wires 411 3. Overall Jc of Cu-Nb-Sn versus Nb
concentration 414 4. Overall J c of CU-V -Ga 414
E. Mechanical Properties 417 1. Mechanical properties of Cu-Nb-Sn 417 2. Pre-stress model 417 3. Mechanical properties of Cu-V-Ga 420
F. Experimental Observations on Connectivity 422 1. Random distribution 422 2. Filament geometry 423 3. Acid test 427 4. Unified perculation-proximity 430
G. Research in Progress 430 H. Scale-up Technologies 431
POWDER METALLURGY
A. B.
C.
D.
Introduction Cold Process 1. Experimental technique 2. Materials selection 3. Results 4. Potential 5. Research in progress Hot Process 1. Experimental technique 2. Results 3. Potential Infiltration Process 1. Experimental technique 2. Results
431
431 432 432 432 434 437 437 440 440 440 440 442 442 442
xviii
V.
VI.
CONTENTS
3. Features 4. Scale-up technology
OTHER PROCESSES
A. B. C. D. E.
Metastable Solid Solution (Stoichiometric) Controlled Precipitation Mechanical Alloying Modified Jelly Roll Energy Research Foundation (ECN) Process
CONCLUDING COMMENTARIES FUTURE DEVELOPMENTS
442 444
444
444 445 445 445 448
448
CHAPTER 7 MECHANICAL PROPERTIES AND STRAIN EFFECTS IN SUPERCONDUCTORS
I.
II.
IIi.
J. W. Ekin
INTRODUCTION 455
455 455 455 455 456
A. Sources of Mechanical Loads in Magnets 1. During fabrication 2. Differential thermal contraction 3. The Lorentz force
B. Mechanical Properties of Superconductors
STRESS-STRAIN CHARACTERISTICS 458
A. B.
Micromechanica1 Model Stress-Strain Characteristics for
Practical Conductors
458
460
EFFECT OF UNIAXIAL STRAIN ON J c ' Hc2 ' and Tc 464
A. B.
C.
D.
E.
Mechanical-Electrical Interaction 464 Jc-e Characteristics for Practical
Superconductors 465 1. Multifilamentary NbTi 465 2. Multifilamentary Nb3Sn 468 3. Multifilamentary V3Ga 470 4. CVD Nb3Ge tape 472 Strain Scaling Law - Prediction of J (B,e) 472 1. Scaling of pinning force curves c 474 2. Strain scaling law 475 3. Application to practical multifilamen-
tary Nb3Sn conductors 478 General Scaling Law - Prediction of J c (T,
B, e) 479 Uniaxial-Strain Criterion for Magnet Design 482
CONTENTS xix
IV.
V.
VI.
VII.
BENDING STRAIN 484
A. Effect of Bending on J c 484 B. Prediction of Bending-Strain Degradation
from Uniaxial-Strain Measurements 486 1. Long twist pitch 486 2. Short twist pitch 487 3. Application 489
C. Bending Strain Limits for Magnet Design 490 D. Methods for Minimizing Bending Degradation 492
FATIGUE
A.
B.
TRAINING
A. B. C.
1. Cabling 492 2. Wind-and-react magnet fabrication 494
Matrix Degradation 1. NbTi 2. Nb 3Sn Micromechanica1 Model
495
495 495 497 497
500
Stress-Relief Model 501 Materials 501 Techniques for Minimizing Training 502 1. Crack arrestors 502 2. Bond breakage and friction 504 3. Programmed winding tension 504 4. Magnet shakedown without quenching 504
SlTh~RY AND FUTURE RESEARCH NEEDS 505
A.
B.
Summary of Material Strain Limits for Magnet Design
Future Research Areas 505 505
CHAPTER 8 PHASE DIAGRAMS
I.
II.
OF SUPERCONDUCTING MATERIALS R. FlUkiger
INTRODUCTION
EXPERIMENTAL DETERMINATION OF HIGH TEMPERATURE PHASE DIAGRAMS
A. Sample Preparation 1. Arc melting 2. r.f. melting in water-cooled
crucibles
511
512
513 513
514
xx
III.
IV.
B. C.
D.
3. r.f. melting in graphite or ceramic crucibles
4. Levitation melting 5. Other melting techniques Homogenization Heat Treatments Direct Observation Methods 1. Differential thermal analysis (DTA) 2. Thermal analysis on levitating
samples (LTA) 3. Electrical resistivity at high
temperatures Indirect Observation Methods 1. Simultaneous stepwise heating 2. Splat cooling of liquid samples 3. Argon jet quenching on solid samples 4. Superconducting "memory"
CONTENTS
514 516 516 516 520 520
522
526 528 528 529 529 530
DETERMINATION OF PHASE DIAGRAMS BELOW 300 K 532
A.
B.
C.
Factors Influencing the Superconducting Data
1. Ordering effects 2. Shielding effects Low Temperature Specific Heat 1. Calorimetric detection of shielding
effects 2. Shielding in multifilamentary Cu-Nb3Sn
wires 3. Calorimetric observation of low
temperature phase transitions Electrical Resistivity Below 300 K
532 532 535 536
536
539
539 544
CRITERIA FOR PHASE STABILITY AND SUPERCONDUCTIVITY 544
A. The Brewer Plots 544 1. Does Au behave like a transition
element? 547 2. The relative stability of intermetallic
phases 547 3. The A15 phase 548
B. Criteria for Superconductivity 550
V. PHASE FIELDS AND SUPERCONDUCTIVITY IN BINARY "ELECTRON COMPOUNDS" 554
A. B. C.
The hcp Structure (A3 type) The A2 Compounds "Atypical" A15 Compounds
554 554 556
CONTENTS xxi
VI.
VII.
1. The V-eRe, Os, Ir, Pt, Au) system 556 2. The electronic structure of electron
compounds: the two-band model 558 3. The Nb-(Os, Ir, Pt, Au) system 560 4. The Cr-(Os, Re, Pt) system 562 5. The Mo-(Re, Os, Ir, Pt) system 562 6. The Ti-system 563 7. Characterization of "atypical"
A15 compounds 563
PHASE FIELDS AND SUPERCONDUCTIVITY IN BINARY AND PSEUOOBINARY "TYPICAL" A15 COMPOUNDS 566
A. B.
C.
D.
E.
F.
G.
The V~3Au and N~3Au systems The Systems V3B (B = Ga, Si, Ge, "AI", and
Sn) 1. V3Ga 2. V3Si and the martensitic transformation 3. V3Ge 4. "V AI" 5. v3gn V.-Based Pseudobinary Compounds 1. V3(Aul-xPt3) 2. Vo 75(Gal~xSix) Nb 3B lB = Ge, Ca, AI, Sn, and Sb) 1. Nb-Ge 2. Nb-Ga 3. Nb-Al 4. Nb3Sn 5. Nb3Sb Nb-Based Pseudobinary Compounds 1. Nb3(Aul-xPtx) 2. Nb3(All_xbx) (B = Ge, Si, Ga, Be, B,
As, ... ) Mo-Based Binaries and Ternaries 1. Mo 3Ge and M03Si 2. M03(Gel-xSix) General Correlations for A15 Compounds 1. The superconducting transition temper-
ature 2. Electronic specific heat 3. Type of formation of A15 compounds 4. Variation of the lattice parameter in
Nb-based A15-type compounds
PHASE FIELDS AND SUPERCONDUCTIVITY IN RHOMBOHEDRAL Mo CHALCOGENIDES (CHEVREL PHASES)
566
567 567 567 569 569 572 572 572 574 574 574 578 578 578 579 579 579
581 581 581 581 581
583 583 583
586
587
xxii
A. B. C. D. E.
F.
Binary Mo-S System CuxMo6S 8 System PbxMo6SS System Mo6SeS' C('lxM06SeS, Pb Mo6SeS General Correlations ~or Rhombohedral
Compounds Comparison with the A15 Compounds
CHAPTER 9 JOSEPHSON JUNCTION ELECTRONICS:
I.
II.
III.
IV.
V.
MATERIALS ISSUES AND FABRICATION TECHNIQUES
M.R. Beasley and C.J. Kircher
INTRODUCTION
DEVICE PRINCIPLES AND MATERIALS REQUIREMENTS
A.
B. C.
Josephson Junctions: Tunnel Junctions and Weak-Link Devices
1. Tunnel junctions 2. Weak-link microbridge Josephson
junctions Other Circuit Elements Summary of Superconducting Device and
Material Parameters of Importance
INTEGRATED CIRCUIT FABRICATION
A.
B. C.
Junctidns with Pb-alloy Electrodes 1. Integrated circuit fabrication 2. Pb-al1oy electrode materials 3. Tunnel barrier Junctions with Niobium Electrodes Comparing Junctions with Nb and
Pb-Alloy Electrodes
STABILITY OF FILMS AND DEVICES DURING CYCLING BETWEEN 350 K AND 4.2 K
A. B. C. D.
Origin of the Cycling Problem Strain Relaxation Mechanisms Film and Device Stability Choosing a Material for Mechanical
Stability
ELECTRON TUNNELING AND TUNNEL BARRIER FORMATION
CONTENTS
590 592 592 595
595 597
605
607
607 60S
613 616
618
618
618 618 627 631 633
636
638
638 641 643
645
646
CONTENTS xxiii
VI.
A.
B.
C.
Theory of Tunneling: Ideal Cases of Interest
Complications that Can Occur in Practical Tunnel Junctions
Tunnel Barrier Formation 1. Grown-oxide barriers 2. Deposited barriers
ADVANCED MATERIALS AND DEVICES
A. B.
C.
D. E.
Materials of Interest Thin-Film Deposition Techniques and
Film Properties Advanced Tunneling Devices 1. Small Tunnel junctions 2. Intermetallic compounds 3. Transition metal alloys Artificial (Deposited) Barriers Weak-Link Microbridges
647
652 654 655 657
658
658
659 663 663 663 670 670 673
CHAPTER 10 CHEVREL PHASE
1.
II.
III.
IV.
HIGH FIELD SUPERCONDUCTORS R. Chevrel
INTRODUCTION
CHEMISTRY AND STRUCTURE
A. Preparation B. Chemistry C. Structure
PHYSICAL PROPERTIES
685
685
685 686 690
697
A. Superconducting Temperatures 697 1. Lattice properties, phonons 697 2. Electronic properties, charge transfer 699
B. Upper Critical Fields 704 C. Magnetism, Coexistence of Magnetism
and Superconductivity 706 D. Critical Currents and Applications 707
NEW MATERIALS PROCEEDING FROM THE LINEAR CONDENSATION OF THE OCTAHEDRAL M0 6 CLUSTERS
A.
B.
In~3Mo15Se19 Containing M0 6 and M0 9 clusters
M2MolSSe19(M = K, _Ba, In, Tl) and ~2Mo15Sl9 (M - K, Rb, Cs) contalnlng M06 and M09 clusters
710
710
712
xxiv
V.
C. D.
CONCLUSION
CHAPTER 11 SUPERCONDUCTING PROXIMITY EFFECT
I.
II.
FOR IN SITU AND MODEL LAYERED SYSTEMS D -:1<. Finnemore
MODEL SYSTEMS
BOUNDARY CONDITIONS AT THE SUPERCONDUCTINGNORMAL INTERFACE
A. B.
Electron Tunneling Thermal Conductivity
III. PHONON SPECTRAL FUNCTION, a2F(W)
IV. SUPERCURRENTS THROUGH NORMAL BARRIERS
V.
VI.
A. B. C.
Thickness Dependence Temperature Dependence Magnetic Field Dependence
FLUX ENTRY FIELDS
IMPLICATIONS FOR IN SITU COMPOSITES
CHAPTER 12 AMORPHOUS SUPERCONDUCTORS C.C. Tsuei
1.
II.
III.
INTRODUCTION
A. B. C.
Preparation Techniques Structural Properties The Anderson Theorem
SYSTEMATICS OF T c
A. B.
Non-transition Metals Transition Metals
ELECTRON-PHONON INTERACTION
CONTENTS
714
716
719
725
726
726 726
728
728
728 728 731
731
733
735
735 736 738
740
740 742
743
CONTENTS
A.
B. C.
The Ratio of Energy Gap to Transition Temperature (2~(0)/kBTc)
a2F(w) and A Origins of Strong Electron-Photon Inter
action 1. Amorphous non-TM superconductors 2. A15 superconductors
IV. CRITICAL FIELDS
A. B.
The Upper and Lower Critical Fields The Temperature Coefficient of
Critical Fields
V. POTENTIAL APPLICATIONS
CHAPTER 13
A. B.
High Field Magnets Josephson Junctions
REVIEWS OF LARGE SUPERCONDUCTING MACHINES
G. Bogner
xxv
743 745
746 748 748
750
750
751
753
753 754
I. INTRODUCTION 757
II. TECHNICAL SUPERCONDUCTORS 757
III. SUPERCONDUCTING MAGNETS FOR HIGH ENERGY PHYSICS 758
IV. LEVITATED TRAINS-ELECTRODYNAMIC LEVITATION SYSTEM 761
V. SUPERCONDUCTING COILS FOR MAGNETIC SEPARATION 766
VI. ROTATING MACHINERY WITH SUPERCONDUCTING WINDINGS 770
A. B.
Generators DC Machines
VII. SUPERCONDUCTING HIGH POWER CABLES
VIII. SUPERCONDUCTING SWITCHES
IX. MAGNET SYSTEMS FOR FUSION REACTORS
X. SUPERCONDUCTING MAGNETS FOR t4HD PLANTS
XI. SUPERCONDUCTING MAGNET ENERGY STORAGE (SME STORAGE)
770 775
779
782
785
796
801
xxvi
CHAPTER 14
CHAPTER 15
SUPERCONDUCTIVITY IN CANADA R. Roberge
RESEARCH ACTIVITIES IN SUPERCONDUCTIVITY IN CHINA
C.-G. Cui and C.-Y. Pang
I. INTRODUCTION
II. BACKGROUND
III. SUPERCONDUCTING ~~TERIALS
IV.
V.
A. B. C. D.
NbTi Nb3Sn V3Ga New Materials
SUPERCONDUCTING MAGNET SYSTEMS
A. B. C.
D. E. F.
Laboratory Magnets High Energy Physics Controlled Thermonuclear Reaction
Technology Superconducting Machines Magnetic Other Applications
JOSEPHSON JUNCTION DEVICES
A. B. C.
Voltage Standard Magnetometer High Frequency Devices
CHAPTER 16 EUROPEAN EFFORTS ON SUPERCONDUCTING MATERIALS
H.C. Freyhardt
CHAPTER 17 REVIEW OF NATIONAL EFFORTS IN MIDDLE EUROPE
H.R. Kirchmayr
1. INTRODUCTION
II. AUSTRIA AND SWITZERLAND
CONTENTS
809
813
813
814
814 816 817 817
817
817 820
820 822 822 824
824
824 825 825
827
837
837
CONTENTS
A. Members in Switzerland B. Expenditures Within COST-action 56
in Switzerland 1. First phase of the COST-action
(1977-1979) 2. Second phase of the COST-action
(1980-1982) C. Projects in Switzerland D. Members in Austria E. Funding Level in Austria F. Projects in Austria
III. CZECHOSLOVAKIA
IV. GDR (GERMAN DEMOCRATIC REPUBLIC)
V. HUNGARY
VI. POLAND
CHAPTER 18 RECENT DEVELOPMENTS IN HIGH-FIELD SUPERCONDUCTORS IN JAPAN
K. Tachikawa
1. INTRODUCTION
II. THE DEVELOPMENT OF V3Ga
A. B.
Surface Diffusion Process Composite Diffusion Process
III. IMPROVEMENTS IN HIGH-FIELD CURRENT-CARRYING CAPACITIES OF COMPOSITE-PROCESSED A15 SUPERCONDUCTORS
}V. SUPERCONDUCTING AND MECHANICAL PROPERTIES OF THE IN SITU PROCESSED V3Ga
V. DEVELOPMENTS IN THE V2Hf-BASE C-15 TYPE SUPERCONDUCTORS
VI. DEVELOPMENTS OF MULTIFILAMENTARY A15 CONDUCTORS IN JAPANESE RESEARCH GROUPS OTHER THAN NRIM
56
56
CHAPTER 19 PROGRAMS ON SUPERCONDUCTING MATERIALS AND MINIATURE CRYOCOOLERS IN THE UNITED STATES
R. Brandt, M. Nisenoff and E. Ede1sack
xxvii
837
838
838
838 839 840 841 841
843
844
844
844
847
847
847 849
849
852
855
858
xxviii
I.
II.
III.
IV.
V.
SUMMARY
INTRODUCT ION
SUPERCONDUCTING MATERIALS
A.
B.
Bulk Materials 1. Liquid Solute Diffusion (LSD) 2. Chemical Vapor Deposition (CVD) 3. Electron Beam Deposition (EBD) 4. Solid State Diffusion (SSD) Thin Films
SMALL CRYOCOOLERS
TRENDS
A. B. C.
Bulk Superconducting Materials Thin-Film Superconducting Materials Small Cryocoolers
CONTENTS
861
861
863
863 863 865 865 865 867
883
891
891 893 896
CHAPTER 20 LARGE-SCALE APPLICATIONS OF SUPERCONDUCTIVITY IN THE UNITED STATES: AN OVERVIEW
I.-
II.
III.
R.A. Hein and D.U. Gubser
INTRODUCTION
LOW FIELD REGIME (H < 2T)
A. B.
c.
General Remarks Power Transmission Lines 1. General Remarks 2. Superconducting AC power transmission
lines (SPTL) 3. Superconducting DC power transmission
lines RF Cavities for Particle Accelerators
INTERMEDIATE FIELD REGIME (2 < H < 5T)
A. B. C.
D.
General Remarks Magnets for High Energy Physics (HEP) Rotating Electrical Machines 1. DC acyclic (homopolar) motors 2. AC machines (generators) Energy Storage Magnets
899
900
900 900 900
901
904 905
906
906 909 912 912 914 917
CONTENTS
IV.
V.
VI.
VII.
HIGH FIELD REGIME (H >5T)
A. B. C.
General Remarks Magnetohydrodynamics (MHD) Magnetically Confined Fusion
SUPERCONDUCTING MATERIALS
HELIUM CONSERVATION
MISCELLANEOUS APPLICATIONS
A. B.
Electromagnetic Launchers Magnetic Separation
CHAPTER 21 REPORTS ON SOME SUPERCONDUCTING MATERIALS COMPANIES IN THE UNITED STATES
I.
II.
III.
IV.
INDEX
AIRCO, INC., CARTERET, NEW JERSEY 07008
A. B.
Introduction Materials Fabrication
INTERMAGNETICS GENERAL CORPORATION, WATERBURY, CONNECTICUT AND GUILDERLAND, NEW YORK.
A. B.
C.
Introduction Manufactured Materials 1. Ductile alloy superconductors 2. A15 superconductors 3. External bronze process Conclusions
SUPERCON, INC.
A. B.
Introduction High Field Superconductors
TELEDYNE WAH CHANG CO., ALBANY, OREGON 97321
A. B.
Introduction Material Supply and Manufacturing
xxix
921
92l 921 923
929
932
934
934 934
939
939 939
942
942 942 942 943 944 944
945
945 945
946
946 946
949
