Yttrium barium copper oxide

  • YBaCuO
  • YBCO

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Yttrium-barium- copper oxide, often abbreviated or referred to as YBCO YBaCuO, a discovered in 1987 family of superconductors of yttrium, barium, copper and oxygen, consisting of the chemical elements, and a critical temperature of 92 K (accordingly minus 181.15 degrees Celsius ) feature. So you belong to the group of so-called high-temperature superconductors.

The development of high temperature superconductors

High-temperature superconductivity (HTSC ) was heralded in 1986 by the discovery of superconducting oxocuprates in the system La -Ba- Cu -O by Johannes Georg Bednorz and Karl Alexander Müller. Studies of Jahn- Teller distorted metal oxides showed that oxocuprates compared to the previously known superconductors have much higher transition temperatures.

This finding triggered a wave of research, which reached a climax with the discovery of YBa2Cu3O7 -x ( also referred to as Y123, YBCO or YBaCuO ). YBa2Cu3O7 -x was the first compound for a transition temperature above the boiling point of liquid nitrogen has been shown with Tc = 92 K. In the following years numerous other oxocuprates were detected with greater structural and chemical complexity. The amazing thing about these compounds and high-temperature superconductivity is that, firstly, according to the BCS theory a transition temperature of about 40 Kelvin can not be explained ( at low temperatures because the thermal energy of the lattice vibrations would actually prevent the formation of Cooper pairs ) and others that it is the material found is not a metallic conductor, but a ceramic.

Probably the most accurately characterized and intensively studied oxocuprate is YBa2Cu3O7 -x, which is often referred to as 123- oxide. The structure of YBa2Cu3O7 can be considered a defect variant of the perovskite type ( AMO3 ) be construed, remain unfilled in the 2/9 of the oxygen positions.

Superconductivity is only the orthorhombic modification with x < 0.6.

Production

Compounds of the type YBa2Cu3O7 -x can be prepared in special furnace processes at up to 900 ° C either yttrium nitrate, barium nitrate, copper nitrate, oxalic acid and urea, or yttrium oxide, barium carbonate and copper ( II) oxide.

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