Date: May 16, 1988
For a world awash in preprints, published papers, and press releases on superconductivity, we have IBM researchers J.G. Bednorz and KA. Miller to thank. Their 1986 article reporting superconductivity in a copper oxide compound at 35 K, opened the floodgates to several hundred superconductivity publications in the early months of 1987.
The accompanying graph, based on data from the Institute for Scientific Information (ISI), show the citation record of the five superconductivity articles that were most cited during 1987 and the first quarter of 1988.
The Bednorz-Müller report (Zeitschrift für Physik B -Condensed Matter, vol. 64, pp. 189-193, September 1986) rode highest on the crest of the publishing tidal wave. By the end of March 1988, it had collected nearly 1,000 citations. An article by M.K. Wu et al. (Physical Review Letters, vol. 58, pp. 908-910,2 March 1987), reporting 93 K superconductivity in an yttrium compound, nearly matched the performance of the Bednorz-Müller paper by late 1987.
Two January 1987 articles, appearing back-to-back in the same journal issue, rose steadily to mid-year and thereafter began to sink slowly. C.W (Paul) Chu et al. (Physical Review Letters, vol. 58, pp. 405-407, 26 January 1987) reported 40 K superconductivity in an La-Ba-Cu-O compound placed under hydrostatic pressure. R.J. Cava et al. (Physical Review Let- ters, vol. 58, pp. 408-410, 26 January 1987, identified in the accompanying graph as "Cava I") achieved 36 K superconductivity by substituting strontium for barium in the mixture.
But a second article by Cava and colleagues at AT&T Bell Labs (Physical Review Letters, vol. 58, pp. 1676-1679, 20 April 1987, here designated as "Cava II") has floated higher and higher, dipping just slightly last quarter.
Why the rise for this paper? "It gives the recipe," explains Robert Cava, who reviewed the graph for The Scientist. "Whereas the other four report discoveries of higher-temperature superconductivity, this paper identifies in exact terms what’s superconducting in Wu’s yttrium compound. That probably accounts for a portion of its continuing citations."
"But also," he says, "that article, and even more so the Bednorz-Müller and Wu papers, are those that most superconductivity researchers have been quoting as the standard references."
During the period from 1983 to 1986, ISI recorded an average of 900 journal articles each year with the words "superconductivity" or "supercondutor(s)" in their titles. In 1987 that number more than doubled—to 2,450. About 750 were from the U.S., 550 were from Japan, and 200 from the Soviet Union. With 125 K superconductivity recently attained in a thallium-based compound, the tide of superconductor research and publications shows no sign of ebbing.