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DISCOVERY OF HIGH TEMPERATURE SUPERCONDUCTIVITY.

LA DECOUVERTE DE LA SUPRACONDUCTIVITE A HAUTE TEMPERATURE.

Author(s) : MULLER K. A., BEDNORZ J. G.

Type of article: Article

Summary

OVER DECADESSUPERCONDUCTIVITY, DISCOVERED IN 1911, COULD ONLY BE OBSERVED IN VARIOUS METALS AND ALLOYS AT VERY LOW TEMPERATURES, INVOLVING THE USE OF LIQUID HELIUM. THERE WAS SLOW PROGRESS TOWARDS HIGHER CRITICAL TEMPERATURES, UP TO 23 K IN 1973, BUT THIS MAXIMUM REMAINED THE SAME UP TO 1986. THE AUTHORS (1987 NOBEL PRIZE OF PHYSICS) DISCOVERED IN ZURICH, IN JANUARY 1986, THE FIRST INDICES OF < HIGH TEMPERATURE > SUPERCONDUCTIVITY IN BARIUM-LANTHANUM-COPPER OXIDES. THEY EXPLAIN REASONS FOR WHICH THEY BECAME INTERESTED IN OXIDES, BASED ON CHAKRAVERTHY'S (GRENOBLE) THEORETICAL PHASE DIAGRAM ENABLING ONE TO GO BEYOND THE BARDEEN-COOPER-SCHRIEFFER THEORY ; THEY WORKED FIRST ON NICKEL AND COPPER, THEN ON BARIUM-LANTHANUM-COPPER OXIDES SYNTHETIZED BY MICHEL AND RAVEAU (CAEN). THEIR DISCOVERY AT THE BEGINNING OF 1986 WAS RAPIDLY CONFIRMED AND COMPLETED BY NUMEROUS LABORATORIES: TOKYO (40 K), BEIJING (46 K), HOUSTON (52 K, THEN 92 K, BY EREST OF THIS NEW CLASS OF SUPERCONDUCTORS IS OBVIOUS (COOLING BY LIQUID NITROGEN INSTEAD OF HELIUM) ; IT MAY BE NECESSARY TO CALL ON NEW THEORETICAL IDEAS IN ORDER TO UNDERSTAND THESE NEW SUPERCONDUCTORS (WHERE ELECTRON GAPS ACT AS POSSIBLE POSITIVE CHARGE CARRIERS). R. T.

Details

  • Original title: LA DECOUVERTE DE LA SUPRACONDUCTIVITE A HAUTE TEMPERATURE.
  • Record ID : 1989-0429
  • Languages: French
  • Source: Recherche - vol. 19 - n. 195
  • Publication date: 1988/01
  • Document available for consultation in the library of the IIR headquarters only.

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