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Magnetic Material

Magnetic Materials - A History of Superconductivity

 
Introduction
Magnetic Properties of Materials
Superconductors
A History of Superconductivity
Molecule-Based Magnets
Spintronics
References

A History of Superconductivity

  • 1908 Dutch physicist Heike Kamerling Onnes produces liquid helium (bp 4.22 K).
  • 1911 Onnes discovers that when mercury is cooled below 4 K is has zero electrical resistance. Mercury becomes the first reported superconducting material.12 Two years later he is awarded a Nobel Prize in Physics for his investigations on the effect of very low temperatures on matter.8
  • 1933 W. Meissner and R. Oschsenfeld observe that when a superconducting material is cooled below its critical temperature (TC) magnetic fields are excluded from the material. This is distinct from a perfectly diamagnetic (zero resistant) material in which there would be no deviation in magnetic field. This becomes known as the Meissner Effect (see Figure 4).13

Figure 4. The Meisner effect.
 

  • 1941 Superconductivity is found in niobium nitride below 16 K.
  • 1962 First commercial superconducting wire (niobium-titanium) developed by Westinghouse.
  • 1972 John Bardeen, Leon Cooper, and John Schrieffer win Nobel Prize in Physics for their theory of superconductivity (BCS theory).8
  • 1975 The first polymeric superconductor (SN)x reported.
  • 1980 The first superconducting (at high pressure) molecular compound, (TMTSF)2PF6 (where TMTSF is tetramethyltetraselenafulvalene, Aldrich product 27,440-2) reported.14


  • 1981 First ambient pressure superconducting molecular compound, (TMTSF)2ClO4, reported.4
  • 1986 Alex Müller and Georg Bednorz synthesize a lanthanum barium cuprate (La2-xBaxCuO4) with a TC of 35 K.15
  • 1987 Bednorz and Müller's group report an yttrium barium cuprate (YBa2Cu3O7) with a TC of 93 K. This is the first reported high-temperature superconductor (HTS), that is, a compound which superconducts above the boiling point of nitrogen (77 K).16,17
  • Bednorz and Müller receive a Nobel Prize in Physics that same year for their discovery.8
  • 1988 A superconducting ceramic (Tl2Ba2Ca2Cu3O10) with a TC as high as 125 K is reported.18
  • 1991 Fullerides of the formula AX@C60 (A = K, Rb, Cs) reported to have superconducting character.5
  • 1993 A mercury barium cuprate (HgBa2Ca2Cu3O10) with a TC of 134 K19 (164 K at 30 Gpa20) is reported. This is the highest TC superconductor to date.
  • 2001 Magnesium boride, MgB2 (Aldrich product 55,391-3) is reported to have superconducting properties (TC = 39 K).6

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