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Out Into the Cold

"Dewar & Onnes," Mike Bogle, University of New South Wales (August, 2009).  [A great blog from a university educator completely unfamiliar with the race between James Dewar, Royal Institute, London, and Heike Kamerlingh Onnes, professor of physics at the University of Leiden, to liquify helium at the beginning of the 20th century.  Bogle comments on the disparate attitudes of Dewar and Onnes toward collaborative research which may have aided the latter's institute to liquify helium first in 1911, and earning the Nobel Prize in 1914 (Yet, when superconductivity was found by Gilles Holst, a research associate at the Leiden Institute, Onnes did not list him as a co-author on the early publications!). Bogle has embedded the 2008 Nova program (see below) with "time links" to relevant scenes.  Make sure your browser has a streaming video app.]
"Absolute Zero," PBS Nova (2008), [The original episode(s), almost two hours in length, unforturnately with ads, so sit back and grab yourself a cyro-cold beer (or two).]

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Superconductivity Yesterday

"Superconductivity: The Day Before Yesterday - Yesterday - Today - Tomorrow," V. L. Ginzburg, Physics - Uspekhi 43, 573 (2000). [A marvelous review of the ghosts of superconductivity, past, present and future, written in the style only Vitaly Ginzburg can create.  The reference bibliography spans the entire scientific history of superconductivity to its date of publication.]
"Further Experiments with Liquid Helium...The Resistance of Pure Mercury at Helium Temperatures," as reported by H. Kamerlingh Onnes, Director of the Physical Laboratory of the Unversity of Leiden, Commun. Leiden 120b (1911). [Arguably the first report, at least in English, of the observation of "zero resistance" in mercury.  Because of the unusual nature and vagaries (at least from a modern viewpoint) of "publication lexicography" in The Netherlands at the time, it can be difficult to actually sort out the time series of events (hopefully, all this will be sorted out by the 100th anniversary in 2011!).  Toward this end, one should also consult the following sources (please observe the inserted comments and Acrobat Bookmarks): Through Measurement to Knowledge (a perspective), KAWA 120b,122b,124c (124c contains the "famous" Hg R vs. T plot), KAWA 133a-d (Observation of Ic in Hg, and Tc in Sn and Pb.  The detection of relatively low levels of "critical current" dashed immediate hopes of lossless transmission lines, which were being touted right from "t=0" 1911).  For an overall summary of work at Onnes' laboratory from 1910 to 1924, see CL S34b (A good discussion of the experimental apparati available at Leiden (photos of representative equipment can be viewed on the website of Boerhaave Museum)...and an observation that low temperatures do not affect radioactivity!), and CL S50a (Contains the speculation that superconductivity may constitute a new state of matter...but it's in French!). For a review of the properties of liquid helium and "pre-Hg" transport measurements (e.g., Pt...we now know that Pt is only superconducting as a powder, 0.02 K), see CL 119, and CL 120a for the low temperature virial properties of argon. CL 160b discusses the superconductivity of Tl and suggests its transport may be "filamentary."  Today we call that "non-bulk."
An Historical Footnote
In the closing paragraph of 133d, Onnes remarks "...I wish to express my thank(s) to Mr. G. Holst, assistant at the Physical Laboratory, for the devotion with which he has helped me..."  We now know that it was Gilles Holst who proposed the purification of mercury by distillation and performed the subsequent experiment that first revealed superconductivity.  Gilles Holst was thus the "Georg Bednorz" of low temperature superconductivity and in today's scientific culture would have justly shared the fame of his better known mentor, as indeed did Bednorz.  To be fair, Holst did go on to become the founding director of Philips Research Laboratory and a Professor at Leiden. I find the following remark by the late Vitaly Lazarevich Ginzburg on early 20th century publication ethics quite cogent: "...Holst himself had not apparently thought of such a demeanor of Kamerlingh Onnes as unjust or unusual.  The situation is not clear to me, and for our generation it is quite unnatural; perhaps 90 years ago morals and manners in the scientific community were totally different."  The upcoming 100th anniversary of Onnes' and Holst's shared discovery will provide an opportunity to clarify the record.
In that regard, the September issue of Physics Today features a fascinating article by Dirk van Delft and Peter Kes, both associated with Leiden today, The Discovery of Superconductivity, containing copies of Onnes' original notes and drawings of the "dewar" system used in the mercury experiments.  One is reminded experiments at liquid helium those days were far more challenging than now.]
"Ein neuer Effekt bei Eintritt der Supraleitfaehigkeit (A New Effect Concerning the Ability to Penetrate a Superconductor)",  W. Meissner and R. Ochsenfeld, Die Naturwissenshaften 44, 787 (1933).  [(In German) Discovery that when a superconductor is cooled in an external magnetic field, that field is expelled from within the superconductor.  It is this effect that differentiates a superconductor from a "perfect conductor."]
"Measurements of the Specific Heat of Thallium at Liquid Helium Temperatures," W. H. Keesom and J. A. Kok, Physica 1, 175 (1934). [The first widely circulated report of a first-order jump in specific heat in a "Type I" superconductor, a major clue to what would become GL theory.]
"On Supraconductivity I," C. J. Gorter and H. Casimir, Physica 1, 306 (1934). [A thermodynamic and phenomenological treatment of the Meissner-Ochsenfeld field expulsion effect, showing that such expulsion lowers the overall free energy and explains the specific heat jump observed by Keesom and collaborators at Leiden.  This paper is an anticipation of the Ginzburg-Landau theory.]
"The Electromagnetic Equations of the Supraconductor," F. London and H. London, Proc Roy. Soc London A149, 71 (1935). [An empirical reformulation of Maxwell's equations to accommodate the Meissner-Ochsenfeld field expulsion effect.  Introduces the key concept of a magnetic field penetration depth.]
"The Discovery of Type II Superconductors (Shubnikov Phase)," A. G. Shepelev, (2010). [In the process of obtaining the original papers of Shubnikov and his collaborators regarding the discovery of what came to be known as "Type II" superconductors in 1936.  Shubnikov was arrested and executed by the Stalinist police the following year.  In the meantime, please read this excellent history of these events by Shepelev.]
"Ginzburg-Landau Theory (Wikipedia)," Zh. Eksp. Teor. Fiz. 20, 1064 (1950). [Can't find the original Russian or a translation...only Wikipedia...sorry]
"Isotope Effect in the Superconductivity of Mercury," E. Maxwell, Phys. Rev. 78, 477 (1950); "Superconductivity of Isotopes of Mercury," C. A. Reynolds, B. Serin, W. H. Wright, and L. B. Nesbitt, Phys. Rev. 78, 487 (1950). [Both these papers were submitted simultaneously on 24 March 1950, each becoming aware of the other's work only a few weeks before at an ONR conference.  Interestingly, earlier attempts at Leiden in 1922 to observe an isotope effect in Pb, and in 1941 in Germany, failed to give any observable effects.  These present experiments suggested the atomic mass, and perhaps lattice vibrations, were a fundamental ingredient in superconductivity.]
"Theory of the Superconducting State. I. The Ground State at the Absolute Zero of Temperature," H. Froehlich, Phys. Rev. 79, 845 (1950). [This paper is the first speculation that lattice vibrations might be involved in superconductivity. However, it deals with the scattering of only one electron, and not pairs. It explains the earlier discovery of the isotope effect, although Froehlich was not aware of its existence when he first submitted this paper.]
"An Experimental and Theoretical Study of the Relation between Magnetic Field and Current in a Superconductor," A. B. Pippard, Proc. Roy. Soc. (London) A216, 547 (1953). [In this paper, Brian Pippard elucidates a fundamental key concept underlying all BCS-like theories of superconductivity, whether strong or weak coupling.]
"On the Theory of Superconductivity: the One-Dimensional Case," H. Froehlich, Proc. Roy. Soc. (London) A223, 296 (1954). [A seminal, but often overlooked paper, of possible relevance to eventual "room temperature perfect conductor." It was employed by Bardeen in 1973 to interpret the, in turned out erroneous, data by the Heeger-Garito U. Penn group claiming observations of superconducting fluctuations in TTF-TCNQ. It does indeed, however, explain the phenomenon of charge density wave (Peierls) transitions ubiquitous to quasi-1D-conductors (e.g., polyacetylene) and a major competitive instability to superconductivity in such structures.]
"Bound Electron Pairs in a Degenerate Fermi Gas," L. N. Cooper, Phys. Rev. 104, 1189 (1956). [Cooper's seminal demonstration that an arbitrarily weak attractive interaction between electrons degenerate at the Fermi surface would lead to their pairing. He speculated that such an attraction could arise from lattice vibrations.]
"On the Magnetic Properties of Superconductors of the Second Group," A. A. Abrikosov, Sov. Phys. JETP 5, 1174 (1957). [Abrikosov's elaboration of the two solutions to the G-L equations depending on the magnitude of the parameter "kappa" which, when less than 1/√2, leads to the formation of vortices and all the physics we associate with Type II superconductors.  See the article by Berlingcourt for the fascinating pre- and post Cold War story of Type II superconductors.]
"Theory of Superconductivity," J. Bardeen, L. N. Cooper and J. R. Schrieffer, Phys. Rev. 108, 1175 (1957). [The BCS Nobel Prize paper.  Finally, an explanation of superconductivity some 46 years after its discovery.  The BCS theory is the crowning theoretical achievement of condensed matter physics in the 20th Century. This paper is also an outstanding review of the past theoretical attempts to explain superconductivity and why they failed.]
"Interaction between Electrons and Lattice Vibrations in a Normal Metal," A. B. Migdal, Sov. Phys. JETP 6, 996 (1958). [An important elaboration of BCS which does not use a perturbation approach to treat the electron-phonon interaction. Instead the interaction is renomalized, showing that pairing occurs for all values of the strength of the e-p coupling.]
"Microscopic Derivation of the Ginzburg-Landau Equations in the Theory of Superconductivity," L. P. Gorkov, Sov. Phys. JETP 9, 1364 (1959). [A landmark paper proving the Ginzburg-Landau equations can be derived from BCS theory with charge 2e.]
"Comparison of the Macroscopic Theory of Superconductivity with Experimental Data," V. L. Ginzburg, Sov. Phys. JETP (USSR) 36, 1930 (1959). [Essentially a comment on the paper of Gorkov pointing out additional "thought" must be given when using data on "small" samples relative to coherence and penetration depths.]
"Interactions Between Electrons and Lattice Vibrations in a Superconductors," G. M. Eliashberg, Sov. Phys. JETP 11, 1364 (1959). [This paper continued the work of Migdal up to a value of the e-p coupling scaled to the ratio of the Debye temperature to the Fermi energy.  Combined with the work of McMillan, the two works form the basis of the computational study of strong coupled superconductors.]
"A Research Investigation of the Factors That Affect the Superconducting Properties of Materials," GE Report AD480235, 15 November 1965. [The classic GE study done under Air Force sponsorship which contains the first detailed study of hysteretic losses in Type II superconductors, otherwise known at the Bean Model.]
"Structure and Properties of High-Field Superconductors,"  J. D. Livingston, GE R&D Center Report (ca. 1969-70). [Jim Livingston's great little review of critical currents and pinning in Type II superconductors, probably still the clearest exposition of these issues and eerily relevant to anisotropic superconductors yet to be discovered.]
"Transition Temperature of Strong-Coupled Superconductors," W. L. McMillan, Phys. Rev. 167, 331 (1968). [The "practical theory" of superconductivity which allowed analytically relating the electron-phonon coupling to tunneling spectroscopy, the so-called alpha-2 F(omega).]
"The Problem of High-Temperature Superconductivity, II," V. L. Ginzburg, Sov. Phys. Uspekhi 13, 335 (1970). [The original exposition of VL's "sandwich" concept as an embodiment for RTSC, better known today as "Ginzburgers."]
"The Description of Superconductivity in Terms of Dielectric Response Function," D. A. Kirzhnits, E. G. Maksimov, and D. I. Khomskii, J. Low Temp. Phys. 10, 79 (1972). [An alternative, and in my view, a far more general approach to fermion-fermion pairing than Eliashberg-McMillan which implicitly is restricted to a phonon-boson interaction.  It employs a momentum-frequency dependent dielectric function approach (or more exactly its inverse) similar to, and perhaps equivalent, to the Lindhard function (see Andrea Benassi's Thesis).  This KMK formalism was used by Gutfreund to analytically examine Bill Little's model for exciton-mediated superconductivity.]
"Transition Temperature of Strong-Coupled Superconductors Reanalyzed," P. B. Allen and R. C. Dynes, Phys. Rev. B 12, 905 (1975). [This paper applies an important correction to the McMillan BCS Debye temperature prefactor, involving a logarithmic average over the total e-p coupling as measured by tunneling spectroscopy.]
"Critical Fields, Pauli Paramagnetic Limiting, and Material Parameters of Nb3Sn and V3Si," T. P. Orlando, E. J. McNiff, Jr., S. Foner and M. R. Beasley, Phys. Rev. B 19, 4545 (1978).  [The appendices of this paper contain a tremendously useful compilation of GLAG equations in various clean and dirty limits.]
"Type II Superconductivity: Quest for Understanding," T. G. Berlincourt, IEEE Trans. Mag. MAG-23, 403 (1987).  [Probably the definitive history of Type II (hard) superconductors.  Especially fascinating are the tribulations of Shubnikov and the complete ignorance in the US of the achievements of Abrikosov due to the curtain of the Cold War.]
"The Critical Current of a Superconductor: An Historical Review," D. Dew-Hughes,Low Temperature Physics 27, 713 (2001). [Probably the most up-to-date summary of the most important parameter for applications, next to Tc.]

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Superconductivity Today

Con Cuidado...The links addressing the discovery of the HTSC copper oxide perovskites emphasizes the contributions of the three IBM Research Laboratories.

"Possibility of Insulator to Superconductor Phase Transition," B. K. Chakraverty, J. Physique-Lettres 40,L-99 (1978). [Alex Mueller cites this paper, and the following two, as his principal inspiration to pursue mixed valent charge transition metal complexes as possible hosts for high temperature superconductivity.]
"Bipolarons and Superconductivity," B. K. Chakraverty, J. Physique 42, 1351 (1981). [A elaboration of the above paper.]
"Jahn-Teller Effect in Itinerant Electron Systems: The Jahn-Teller Polaron," K.-H. Hoeck, H. Nickish and H. Thomas, Helvetica Physica Acta 56, 237 (1983). [Mueller attributes great importance to this paper as pointing to tetragonal symmetry as hosting strong coupling of itinerant electrons to a Jahn-Teller distortion such as found in mixed valent compounds.  Quite curiously, several years after the publication of this paper, Hoeck seems to have "disappeared" from the scientific scene.]
"Oxygen Intercalation in Mixed Valence Copper Oxides Related to the Perovskites," C. Michel and B. Raveau, Rev. Chim. Min. 21, 407 (1984). [This is a very old journal and has a number of continuations.  I have not been able to obtain a copy yet.  It contains the first Caen paper on LA-4-1-5-13 that Bednorz found.] 
[Note added 09/24/2013:  Thanks to Eric Hellstrom (ASC Tallahassee), he and his students have found this historical jewel...enjoy and make sure you cite them!]
"The Oxygen Defect Perovskite BaLa4Cu5O13.4, a Metallic Conductor," C. Michel, L. Er-Rakho and B. Raveau, Mat. Res. Bull. 20, 667 (1985). [An elaboration of measurements reported in the Revue de Chimie Mineral paper.  Shown are the thermopower and resistivity data from 200 - 550 K.  Had measurements been made down to liquid helium temperatures, it is likely the Caen Group would have found some traces of superconductivity, especially in the thermopower.  Apparently, the main interest of these workers in this material was for catalysis applications and high temperature oxygen sensors for use in, for example, cement kilns.]
"Possible High TC Superconductivity in the Ba-La-Cu-O System," J. G. Bednorz and K. A. Mueller, Z. Phys B - Condensed Matter 64, 189 (1986) [The discovery publication.  Ironically, Bednorz chose initially the only copper oxide perovskite that's metallic at all temperatures and superconducting at none, but which is extremely difficult to make single phase.  It was soon recognized that it was a minor secondary phase responsible for the appearance of superconductivity and they were on their way.  There is quite a story behind this paper.]
"Susceptibility Measurements Support High TC Superconductivity in the Ba-La-Cu-O System," J. G. Bednorz, M. Takashige and K. A. Mueller, IBM Report RZ 1537, 19 November 1986. [This link is actually to a preprint received on 15 October 1986 by Rick Greene from Alex Mueller (with autograph!).  The Zuerich workers, contrary to popular belief, in reality were the first to confirm their own discovery.]
"Susceptibility Measurements Support High TC Superconductivity in the Ba-La-Cu-O System," J. G. Bednorz, M. Takashige and K. A. Mueller, Europhys. Lett. 3, 379 (1987). [The paper resulting from the above preprint. Read the note added prior to publication.]
"High Tc Superconductivity in La-Ba-Cu Oxides," S. Uchida, H. Takagi, K. Kitazawa, and S. Tanaka, Jap. J. Appl. Phys. 26, L1 (1987). [The first "outside IBM" publication to verify the Zuerich Lab discovery ]
"High Tc Superconductivity in La-Ba-Cu Oxides. II.- Specification of the Superconducting Phase," H. Takagi, S. Uchida,  K. Kitazawa, and S. Tanaka, Jap. J. Appl. Phys. 26, L123 (1987). [A curious paper.  Appears to be a "catch-up" to cover experiments carried out after submission of the above. ]
"Flux Trapping and Superconductive Glass State in La2CuO4-y:Ba," K. A. Mueller, M. Takashige and J. G. Bednorz, Phys. Rev. Letters 58, 1143 (1987). [This is the third remarkable paper out of IBM Zuerich which started the whole subsequent study of flux dynamics in these anisotropic superconductors.]
"Superconductivity at 93 K in a New Mixed-Phase Y-Ba-Cu-O Compound at Ambient Pressure," W. K. Wu, et al., Phys. Rev. Letters 58, 908 (1987). [The Wu-Chu discovery of YBCO...but not 1-2-3.]
"Superconductivity Above 90 K in the Compound YBa2Cu3Ox: Structural, Transport, and Magnetic Properties," P. M. Grant, R. B. Beyers, E. M. Engler, G. Lim, S. S. P. Parkin, M. L. Ramirez, V. Y. Lee, A. Nazzal, J. E. Vazquez and R. J. Savoy, Phys. Rev. B35, 7242 (1987).  [First Report of the "1-2-3" Crystal Structure and Material Processing Conditions.  More story to follow. Until then, go here.]
"Chu Talk: Woodstock of Physics," 1987 APS March Meeting, 3/18-19/1987, Hilton NYC. [Paul Chu's mixed phase discovery engendered the "Woodstock of Physics."  Please watch.]
"Mueller Talk: Woodstock of Physics," 1987 APS March Meeting, 3/18-19/1987, Hilton NYC. [Pay particular attention to the Alex' last slide...there's an interesting story within his selection.}
"Grant Talk: Woodstock of Physics," 1987 APS March Meeting, 3/18-19/1987, Hilton NYC. [What we accomplished in IBM Almaden, San Jose, 4 January 1987 to 4 March 1987.  Please watch.]

"Superconductivity Above Liquid Nitrogen Temperature: Preparation and Properties of a Family of Perovskite-Based Superconductors," E. M. Engler, V. Y. Lee, A. I. Nazzal, R. B. Beyers, G. Lim, P. M. Grant, S. S. P. Parkin, M. L. Ramirez, J. E. Vazquez and R. J. Savoy, J. Am. Chem. Soc. 109, 2848 (1987).  [The best paper hands down, written by Ed Engler, that came out of the 1987 APS Meeting of March, 1987, the "Woodstock of Physics."  This is the first report, which I was honored to give at "Woodstock," on the structure, processing and properties, of the rare earth substitutions for yttrium.  There are two retrospective "blunders" in this paper.  One was the attribution for the lack of superconductivity in Pr-1-2-3 to the absence of the orthorhombic phase, which was due to low oxygen concentration, later the subject of a more comprehensive paper.  The other was reporting superconductivity in the Ba-Ca-Sr fractional substitution which turned out to be a blown labeling of samples!  What the hell...we were in battle!]

"Evidence for Superconductivity in La2CuO4," P. M. Grant, S. S. P. Parkin, V. Y. Lee, E. M. Engler, M. L. Ramirez, J. E. Vazquez, G. Lim, R. D. Jacowitz and R. L. Greene, Phys. Rev. Letters 58, 2482 (1987).  [This was a remarkable discovery.  In January, 1987, Rick Greene and I observed zero thermopower at 41 K, a clear signature of superconductivity, in an "undoped" sample of La2CuO4 given us by Georg Bednorz, one which was completely insulating!  Read the paper to find out what happened.  High-Temperature superconductivity could have been discovered in 1954!]
"The Discovery of a Class of High Temperature Superconductors," K. A. Mueller and J. G. Bednorz, Science 237, 1133 (1987). [Story of the discovery by the discoverers.]
"Critical-Current Measurements in Epitaxial Films of YBa2Cu3O7-x Compound," P. Chaudhari, et al., Phys. Rev. Letters 58, 2684 (1987). [The first epitaxial films of Y-123 were made the evening of Monday,10 March 1987, the week before Woodstock, by Bob Laibowitz, using structural and processing data supplied by IBM Almaden.]
"Orientation Dependence of Grain-Boundary Critical Currents in YBa2Cu3O7-δ Bicrystals," Dimos, et. al, Phys. Rev. Letters 61, 219 (1987). [This is the famous "Dimos" paper that provided the science to jump start the worldwide development of coated conductor, or Gen 2 tape.]
"Remarks at the Federal Conference on Commercial Applications of Superconductivity," R. W. Reagan, International Ballroom, Washington Hilton Hotel, 11:47 AM, 28 July 1987. [I was there.  One of two (along with Praveen Chaudhari) invited representatives from IBM.  Reagan gave an absolutely marvelous speech (he was an actor, and I learned later was coached by Ed Teller and Ralph Gomory.  What many deemed unusual was that all of the President's senior cabinet members attended.  This was a time when there was a fear the Japanese would again exploit another American technology, as was supposed to have happened with VCRs. A magic moment.]
"Resistive Transition of High Temperature Superconductors," M. Tinkham, Phys. Rev. Letters 61, 1658 (1988).  [This paper scared the hell out of us when it appeared, because it implied the newly discovered HTSC compounds may not be practical because of thermal depinning of the Abrikosov vortex lattice. Its appearance engendered a column in Science by Robert Poole, "Superconductivity: Is the Party Over?" Tinkham concludes that a future room temperature superconductor may indeed be in the superconducting state, but not have zero resistance!  This is a great problem for future research.]
"Superconductivity: Is the Party Over?," R. Poole, Science 244, 914 (1988). [Column inspired by Tinkham's article supported by some of David Bishop's flux lattice melting work at Bell Labs.  The piece quotes a number of industrial leaders to the effect that "we're not going to quit."  No major corporation has a superconductivity program today, and one of them that did now belongs to a French company.]
"The Development of Superconductivity Research in Oxides," K. Alex Mueller (Monograph, date uncertain, ca. 1998-99). [The description of the science background and Mueller's thinking that led to the eventual discovery of high temperature superconductivity in the copper oxide perovskites.]
"High-Temperature Superconductivity (History and General Review)," V. L. Ginzburg, Sov. Phys. Usp. 34,283 (1991). [Written in Ginzburg's delightful wry English style, containing his reflection on the recent discoveries of superconductivity in the cuprates and implications for the future.]
"Superconductivity at 39 K in Magnesium Diboride," J. Nagamatsu, N. Nakagawa, T. Muranaka, Y. Zenitani and J. Akimitsu, Nature 410, 63 (2001).  []
"Ich war wie in Trance," NZZ am Sonntag, 21 Januar 2006, p. 67.  [An interview (in German) of George Bednorz in the Swiss National Sunday newspaper on the occasion of the 20th anniversary of his observation of zero resistance.  The "trance" refers not to the moment of discovery, but when he received the Nobel Prize and probably had to dance with the Queen of Sweden.]

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Superconductivity Tomorrow

"Macroscopic Theory of Superconductivity: Introduction," F. London, Superfluids I, (John Wiley and Sons, 1950), p.9. [Bill Little's inspiration.  Incredible.  Way before BCS and that a "bosonic field" may be crucial to superconductivity.)
"Possibility of Synthesizing an Organic Superconductor," W. A. Little, Phys. Rev. 134, A1416 (1964). [In this paper, Little examines and elaborates a speculation by F. London that macromolecules might exhibit superfluid-like properties in the context of the BSC model formulated a few years earlier.  However, in the molecular structure proposed by Little, excitons on polarizable side group molecules replace phonons as the "boson glue" pairing carriers on a conducting polymer backbone. Curiously, Bill speculates that such a structure might be capable of self-replication or "reproduction."]
"Superconductivity at Room Temperature," W. A. Little, Scientific American 212, 21 (1965). [This was the paper that inspired Rick Greene and myself to begin our (to date unsuccessful) search for the realization of Bill's model in charge-transfer and polymer organics.  You can't always get what you want...go to SuperTunes. ]
"The Problem of High-Temperature Superconductivity, II," V. L. Ginzburg, Usp. Fiz. Nauk 101, 185 (1970) [Sov. Phys. Usp. 13,335 (1970).   [Mandatory reading prior the rest of this page.  Ginzburg's formalism in this paper underlies all that follows.]
"Dynamic Effective Electron-Electron Interaction in the Vicinity of a Polarizable Molecule," W. A. Little and H. Gutfreund, Phys. Rev. B 4, 817 (1971).  [Numerical calculation of the spatial, but not momentum, dependence of the electron-exciton coupling.]
"The Description of Superconductivity in Terms of Dielectric Response Function," D. A. Kirzhnitz, E. G. Maksimov, and D. I. Khomskii, J. Low. Temp. Phys. 10, 80 (1973). [This paper, received by the publishers in May, 1972, became the base theoretical framework for the Davis, Gutfreund and Little classic model for room temperature superconductivity.  Why has not some ambitious graduate student implemented the KMK formalism in a DFT framework to assess any given microscopic model based on the "Little Model"?]
"Proposed Model of a High-Temperature Excitonic Superconductor," D. Davis, H. Gutfreund, and W. A. Little, Phys. Rev. B 13, 4766 (1976).  [The bottom line is that a very particular exciton-fermion coupling k-space dispersion is required to favor superconducting pairing over dimerization into a static Peierls-Froehlich state.]
"Model for an Exciton Mechanism of Superconductivity," D. Allender, J. Bray and J. Bardeen, Phys. Rev. B 7, 1020 (1973). [Speculation that carries at a metal-semiconductor interface may couple to excitons in the semiconductor leading to a Little-like pairing (curiously there is no reference to any of Little's papers).  Many have searched for this effect, and none (reproducible) have been found.]
"Comment on 'Model for an Exciton Mechanism of Superconductivity'," J. C. Inkson and P. W. Anderson, Phys. Rev. B 8, 4429  (1973). [Claims a technical error was made by ABB.]
"Comment on 'Model for an Exciton Mechanism of Superconductivity' -- A Reply," D. Allender, J. Bray and J. Bardeen, Phys. Rev. B 8, 4433 (1973). [Asserts the IA model does not correspond to theirs. Still no clear experimental one way or the other.]
"June 2005 Notre Dame Workshop on the Possibility of RTSC," [Abstract List]
"Design for a Room Temperature Superconductor," W. E. Pickett, BES Workshop on Superconductivity, May 2006.  [Better bone up on Diophantine problems before reading this.  A review of Fibonacci sequences may be useful as well. I am NOT kidding!]
"Researchers Find Extraordinarily High Temperature Superconductivity in Bio-Inspired Nanopolymer," Paul M. Grant, Physics Today, May 1998. [My whimsical SciFi essay covering the great discovery in 2028 of an embodiment of Bill Little's model of exciton mediated superconductivity. You eventually "get what you need." (see SuperTunes)]

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Power Applications


Application Surveys/Workshops
General Power Applications Anthology
Superconducting Cable Anthology

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Application Surveys/Workshops

"Research Opportunities in Superconductivity," M. Tinkham, M. R. Beasley, D. C. Larbalestier, A. F. Clark and D. K. Finnemore, Report on the Workshop on Problems in Superconductivity, 22-23 August 1983, Copper Mountain, CO (Sponsored by NSF, ONR and NBS), November, 1983. [This workshop was held against the background of a substantial decline in funding for superconductivity by Federal agencies and the impending decision taken by IBM during the writing of this report to scale back its Josephson computer project.  On page 12 one can find the phrase penned by Mac Beasley, "At the extreme forefront of research in superconductivity is the empirical search for new superconductors...," which was quoted by Bednorz and Mueller as the first line of their discovery paper.  This report has only this one citation in the technical literature, but what a citation!  A lesson to be not try to justify basic research on the expectation of applications.  By the way, this report focuses overwhelmingly on electronics...the only mention of a power application is SMES.]
"Superconductors: The Long Road Ahead," S. Foner and T. P. Orlando, MIT Technology Review, February/March 1988, p. 36.  [Published the year following the YBCO discovery, this piece expresses great caution over the high expectations prevalent during this period.  The article is a very good survey of past superconductivity application attempts, their successes and failures, and the impact HTSC might or might not have in the future.]
"Report on Discussions with Utility Engineers about Superconducting Generators," D. Forbes and R. Blaugher, NREL/TP-413-20668, March 1996.  [Bottom Line: The major advantage perceived for HTSC generators was their projected low life-cycle costs.  Most respondents did not feel a significant US market would develop earlier than 15 - 20 years from the date of the report.  As far as I know, with the possible exception of a very small LTSC unit in Japan, no superconducting generators are deployed or planned for deployment anywhere in the world at present.]
"The US Market for High-Temperature Superconducting Wire in Transmission Cable Applications," D. Forbes, NREL/TP-450-20667, April 1996.  [This report summarizes a series of interviews with utility engineers on the market potential for HTSC cables, wires and tapes.  A number of interesting anecdotes are related which give insight into various aspects of utility culture.  The report concludes that HTSC wire sales for cables would reach $66 M in 2006.  The future is hard to predict.]
"Power Applications of Superconductivity in Japan and Germany," D. Larbalestier, et al., WTEC Panel Final Report ISBN 1-883712-46-7, September 1997.  [The infamous male bonding trip featuring lost colleagues and broken laptops.  This report had major impact on increasing the DOE superconductivity appropriation thereafter by 60%.]
"HTS Cable -- Status, Challenge and Opportunity," A. M. Wolsky, International Energy Agency Report, 2 December 2004.  [Alan Wolsky's "Magnum Opus," 407 pages of everything you need or would ever want to know about superconducting cables.  Lots of good tables on conventional HVDC transmission lines and cables installed worldwide.]
"IASS Workshop -- Long Distance Transmission," Organized by C. Rubbia, IASS-Potsdam, 12-13 May 2011.
[This workshop focused on a vision encompassing the transmission of several gigawatts of solar power from North Africa to Central Europe via a network of high capacity HTSC dc cables running across the Mediterranean to Italy and Spain and hence northward.  It brought together experts in many areas and represents the state of the art at the time.  This link brings you to the program agenda and copies of the presentations delivered.]

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General Power Applications Anthology

"Superconductivity and Electric Power:  Promises, Promises...Past, Present and Future," P. M. Grant, IEEE Trans. Appl. Super. 7, 112 (1997).  [Based on a Plenary Lecture at the 1996 Applied Superconductivity Conference held in Pittsburg. An in your face review of where power applications have been, were at in 1997, and where they might be going.  Contains a description of the "electricity pipe" concept of Grant, Schoenung and Hassenzahl]

"Cost Projections for High Temperature Superconductors," P. M. Grant and T. P. Sheahen,, Applied Superconductivity Conference, Palm Springs, CA, 1998. [An engineering-economy based approach to estimating eventual cost/performance of both Generation 1 (OPIT/BSCCO/Ag) and Generation 2 coated conductor (textured YBCO) HTSC tape.  Unlike wires made from non-superconducting metals, e.g., copper, the cost/performance in $/kAŚm of HTSC tapes is highly application specific and cannot be reduced to a single number.]
"Potential Electric Power Applications for Magnesium Diboride," P. M. Grant, Mat. Res. Soc. Symp. Proc. 689, 3 (2002).  [A quite controversial paper showing magnesium diboride promises to be cost competitive for power transformer application.]
"Superconductivity for Electric Systems 2005 Annual Peer Review," August 2-4, 2005, L'enfant Plaza Hotel, Washington, D.C. [Link to the latest DOE Office of Electricity superconductivity program content, containing downloadable pdfs of the talks.]
"Superconductivity Technology Center at LANL," [Home page at Los Alamos, with detail on their coated conducting program and links to other sites.]
"High-Temperature Superconductivity (HTS) R&D at ORNL," [Oak Ridge superconductivity home page containing details of its program in wire development and power applications.]
"DOE Office of Electricity Delivery & Energy Reliability - Superconductivity Program," [Home page of the DOE program in power applications of superconductivity.]
Navigant Report: High Temperature Superconductivity Market Readiness Review  [DOE commissioned report on current state of HTSC technology and when market penetration is likely to occur and where.]

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Superconducting Cable Anthology

"Prospect of Employing Conductors at Low Temperature in Power Cables and in Power Transformers," K. J. R. Wilkinson, Proc. IEE (London) 113, 1509 (1966).  [First serious consideration of cryoresistive power cables, including Nb at 4 K operating in the Meissner state!]

"Superconducting Lines for the Transmission of Large Amounts of Electric Power over Great Distances," R. L. Garwin and J. Matisoo, Proc. IEEE 55, 538 (1967). [A Classic!  All subsequent considerations of superconducting dc cables derives from Garwin-Matisoo. This paper is necessary reading for anyone interested in power applications of superconductivity.]
"Multiple Use of Cryogenic Fluid Transmission Lines,"  J. R. Bartlit, F. J. Edeskuty and E. F. Hammel,  Proc. ICEC4, Eindhoven, 24/26 May 1972. [This prescient study from LANL explores the dual delivery of methane and/or hydrogen as energy agents in a "SuperCable" concept.  However, neither serves as a cryogen...liquid hydrogen was necessary...the discovery of high temperature superconductivity was still 13 years in the future!]
"dc Superconducting Power Transmission Line Project at LASL," ed. F. J. Edeskuty, US DOE Division of Electric Energy Systems, 1 November 1972 - 30 September 1979, Progess Report 24 (Final).  [Massive and inclusive study of a large capacity, 5 GW SCDC cable employing Nb3Sn, sponsored by DOE and the Philadelphia Electric Company (PECO) representing the interests of several eastern utilities (this was "before EPRI").  The project was discontinued after building and testing a few meters of conductor due to lack of funding and lack of utility interest (Thanks to Dean Peterson of LANL for making this report public).]
"Refrigeration and Heat Transfer in Superconducting Power Lines," D. E. Daney and R. H. Hammond, NIST Interim Report 275.05-75-2, April 1975.  [An interesting study of the use of slush hydrogen as cryogen for an Nb3Ge dc cable.  No intention to use the hydrogen as an energy source in and of itself is discussed.]
"A Study of Refrigeration for Liquid-Nitrogen-Cooled Power Transmission Cables," R. C. Longworth and K. F. Schoch, Advances in Cryogenic Engineering, v.25, p.585 (1979).  [An early and classic paper on the engineering economy of cryocooled cable designs, superconducting or otherwise.  Thanks to Bill Hassenzahl for bringing this document to my attention.]
"Practical Conclusions from Field Trials of a Superconducting Cable," P. A. Klaudy and J. Gerhold, IEEE Trans. Mag. MAG-19, 656 (1983).  [The first superconducting cable to be installed on a grid (near Arnstein, Austria).  It used Nb at 6.5 K as the superconductor and had a capacity of 60 kV at 1000 A and operated continuously from 1977-80.  It may be that the Nb was operated in the Meissner state...there is no mention of ac losses.  The emphasis was on the flexible design, rather than the superconducting properties.]
"Performance Summary of the Brookhaven Superconducting Power Transmission System," E. B. Forsyth and R. A. Thomas, Cryogenics 26, 599 (1986).  [A 1000 MVA, three phase ac cable built using NbTi at 4 K and tested at Brookhaven National Laboratory in the years just preceding the discovery of high temperature superconductivity.  The project was technically successful, but major utilities did not think the technology economically feasible (I know this information directly from several "personal communications.").]
"Design Concepts for a Superconducting Cable," J. Engelhardt, EPRI Research Report TR-103631, September (1994).  [This is a landmark resource focusing fundamental design approaches to superconducting cable deploying the newly discovered HTSC copper oxide materials.  Con is 534 pages...and its history chapters are incomplete (I know...I was present at the Revelation!).]
"Superconducting Current Transfer Devices for Use ith a Superconducting LVdc Mesh," B. K. Johnson, R. H. Lasseter, F. L. Alvarado, IEEE Trans. Appl. Supercond. 4, 216 (1994).  [The original study pointing out the inherent instability of "Kirchoff Type" networks interconnected by "perfect conductors," proving "resistors" need to be appropriately inserted to prevent chaotic runaway.  For the latest, go here.]
"A dc Transmission Cable Prototype Using High-Temperature Superconductors," T. P. Beales, et al., Supercond. Sci. Technol. 9, 43 (1995). [The first attempt at an HTSC cable, at least a short one. The design is an interesting one, targeting a 400 km European "ring buss" with a 400 MW, 40 kV, 10 kA capacity with cold He gas at 4.2 K blown in one end and warming to 40 K at the other, well within the critical parameter limits of Bi-2223 throughout that range.]
"System Study of Long Distance Low Voltage Transmission Using High Temperature Superconducting Cable," S. M. Schoenung, W. V. Hassenzahl and P. M. Grant, EPRI Report WO8065-12, March, 1997.  [This study was inspired by a talk I heard from ABB at the 1996 World Energy Conference in Yokohama, Japan, which compared the cost effectiveness for well head generation at a vast natural gas reserve such the Qatar region in the Persian Gulf and transport over HVDC lines.  We studied a third alternative, that using a superconducting "e-pipe" to transport power from Qatar to a future Egyptian-Palestine-Israel-Syrian industrial complex, and concluded this alternative was attractive for distances greater than 500 miles.]
"Superconducting Cable Construction and Testing," D. von Dollen and J. Daley, Final Report 1000160, November 2000. [This project was better known as the "EPRI/Pirelli Cable," and resulted from studies performed by EPRI and Pirelli in the early 1990s.  The intent was the design and construction of a 50-m long US standard "pipe type" cable to retrofit 115 kV ac cables with an increased 3-phase capacity to 400 MVA.  The design did not have a superconducting shield which simplified the insulation package (so-called "room temperature dielectric"), but exposed each phase to induced co-phase ac losses in addition to those arising from "self-current" flow.  This design was the basis for the Detroit-Edison demonstration, NKT's Copenhagen Airport, and China's Puji substation.  It was during final testing of this cable that the "blister/balloon" problem manifested, arising from leakage of liquid nitrogen into the BSCCO filaments through pinholes in the Ag tape, leading to its literal "exploding" when the cable was warmed up.  AMSC solved this by later solder-cladding the silver tapes with stainless steel.  Since this issue was considered proprietary at the time, there is no discussion of it in this report.
"ac Loss in Superconducting Power Cables," M. Daeumling, et al., Studies of High Temperature Superconductors (ed. A. Narlikar, Nova Science Publishers), Vol. 33, p. 73 (2000).
Probably the best treatise on ac losses in print.  Written by the design team of the Copenhagen Airport Cable.]
"Copenhagen Airport Demonstration," Dag Willen, NKT Cables Press Release, 28 May 2001.         [An RTD design like Detroit Edison.  Worked well, but no follow-on project.  The NKT superconductivity unit was later sold to Nexans.]
"China's 30m, 35kv/2kA ac HTS Power Cable Project," Ying Xin, et al., EUCAS 2003.  [This project was essentially "Detroit-Edison without cryostat leaks" and performed to its specifications perfectly.  Unfortunately, there are now plans currently in place to follow-on.]]
"Field Demonstration of a 24-kV Warm Dielectric Superconducting Cable at Detroit Edison," S. Eckroad and N. Kelly, EPRI FY2003 Annual Progress Report 1002040, Technical Update, March 2004. [The Detroit-Edison demonstration remains today the most realistic deployment of a superconducting cable, three cables, 120-m each, threaded though 50-year old clay ducts containing five 90-degree bends approximately 2-m radius of curvature.  Unfortunately, the cryostat welds contained a number of martensitic phases resulting in vacuum leaks which prevented the cable from being fully energized at specification voltage.  However, the critical current and ac loss properties of the superconducting tape were measured and found to have undergone little significant degradeation during the cablve installation.  A system study associated with the project on the impact of coaxial (shielded) superconducting cables resulted in demonstrating the network advantages a very low inductive reactance cable might present in utility operation.
"R&D of 22.9 kV/50 MVA HTS Transmission Power Cable in Korea," J. Cho, Kunming Symposium, 24 June 2004. [Review of the entire Korean program by all participating agencies and not limited to cables.]
"Feasibility of Electric Power Transmission by DC Superconducting Cables," P. Chowdhuri, C. Pallem, J. A. Demko and M. J. Gouge IEEE Trans. Appl. Supercond 15, 3917 (2005). [Study of  GW and 500 MW SCDC cables.  Emphasis is on cryogenics, inverter/converter issues and harmonic control]
"Southwire HTS Cable Program Overview," D. Lindsay, 2005 US DOE Peer Review, 2 August 2005 [Altogether, this is one of earliest of US HTSC cable programs.  The 30-m installation at Southwire's Carrollton, GA plant has been in operation almost continuously for six years. The follow-on project will be installed in the Columbus, OH Bixby substation.  This is an adaptation of a conventional triaxial design wherein all three phases are enclosed.  The HTSC cable will be 200-m, 13.2 kV, 1000 A/phase 69 MVA circuit.]
"Albany Cable Project Progress Update," C. Weber, R. Lee and K. Hayashi, 2005 US DOE Peer Review, 2 August 2005. [Cable demonstration at a Niagara Mohawk substation using Sumitomo's "3-in-1" cable design. They plan to have a 15-m segment using Gen 2 YBCO tape.]
"LIPA Project Overview," 2005 US DOE Peer Review," 2 August 2005. [Long Island Power Authority 610-m 136 kV, 2400 A cable project with Nexans and American Superconductor.]
"HTS Transmission Network Will Be the Key of 21st Century's Power Grid," R. Hata,  Kunming Symposium, 24 June 2004.[A survey of all tape and cable programs in Japan by Ryosuke Hata of Sumitomo Electric Industries.]
"Getting the Metrics Right," D. Lindsay, 2006 DOE Wire Development Workshop, 30 January 2006, St. Petersburg, FL.  [A thoughtful appraisal the present approach to measuring and reporting "metric" presumed critical to commercial acceptance.  Lindsay suggests adopting a new metric with units "$/system-MVA/meter/30yr life."]
"A Superconducting DC Cable," W. Hassenzahl, B. Gregory, S. Eckroad, S. Nilsson, A. Daneshpooy and P. Grant, EPRI Final Report 1020458 (Project Manager, S. Eckroad), December 2009. [This report culminates almost five years of effort by the coauthors underwritten by the Electric Power Research Institute.  It at present is the definitive study of the design and properties of SCDV cables. For more EPRI research on power applications of superconductivity, visit]
"Study on the Integration of High Temperature Superconducting DD Cables with the Eastern and Western North American Power Grids," T. Overbye, P. Ribeiro, and T. Baldwin, EPRI Final Report 1020330 (Project Manager, S. Eckroad), November 2009. [This report discusses a model multi-tap superconducting dc cable system capable of carrying up to 10 GW over 1000 mile distances, and the control of inevitable instabilities inherent in a network of "perfect conductors."]
"Transient Response of a Superconducting DC Long Length Cable System Using Voltage Source Converters," S. Nilsson and A. Daneshpooy, EPRI Final Report 1020339 (Project Manager, S. Eckroad), December 2009. [This report examines the application of "voltage source converters (VSC)" to multi-tap "relatively low voltage" SCDC cable networks. VSC electronics are analogous to "field effect transistors," as opposed to present "current source controllers" used in HVDC inverter/converter stations that are similar in operation to the original Shockley-Bardeen junction transistors.  As every electronic engineer knows, an "infinite input impedance" active device, like the old fashioned vacuum tube triode, allows for far simpler circuit design and control.]

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Electronic Applications



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"Magnetocardiography," Cardiomag Imaging, Inc., 15 May 2006. [SQUIDS, "Superconducting Quantum Interference Devices," are capable of detecting extremely small magnetic fields of the order 10^-15 T.  All nerve-generated biological functions employ electric currents and thus generate magnetic fields in principle detectable by SQUIDS.  One notable use has to measure magnetic fields emanating from the brain, a technique called magnetoencephalography (MEG).  In recent years, SQUID technology has been extended to detect various heart pathological conditions, called magnetocardiography (MCG). This link opens an introductory pamphlet.  For more detail, including videos of actual images and medical relevance, click here.

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