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Thallium barium calcium copper oxide, or TBCCO (pronounced "tibco"), is a family of high-temperature superconductors having the generalized chemical formula Tl''m'' Ba2 Ca''n''−1 Cu''n'' O2''n''+''m''+2.
Tl2Ba2Ca2Cu3O10 (TBCCO-2223) was discovered in Prof. Allen M. Hermann's laboratory in the physics department of the University of Arkansas in October 1987 by the post-doctoral researcher Zhengzhi Sheng and Prof. Hermann. The bulk superconductivity in this material was confirmed by observations of magnetic flux expulsion and flux trapping signals (under zero field cooled and field cooled conditions) with a SQUID
Thallium-based high-temperature superconductors
High-temperature superconductors Thallium compounds Barium compounds Calcium compounds Copper(II) compounds Oxides {{chem-stub
Thallium barium calcium copper oxide, or TBCCO (pronounced "tibco"), is a family of high-temperature superconductors having the generalized chemical formula Tl''m'' Ba2 Ca''n''−1 Cu''n'' O2''n''+''m''+2.
Tl2Ba2Ca2Cu3O10 (TBCCO-2223) was discovered in Prof. Allen M. Hermann's laboratory in the physics department of the University of Arkansas in October 1987 by the post-doctoral researcher Zhengzhi Sheng and Prof. Hermann. The bulk superconductivity in this material was confirmed by observations of magnetic flux expulsion and flux trapping signals (under zero field cooled and field cooled conditions) with a SQUID magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
in the superconductor laboratory of Timir Datta
Timir Datta is an Indian-American physicist specializing in high transition temperature superconductors and a professor of physics in the department of Physics and Astronomy at the University of South Carolina, in Columbia, South Carolina.
Earl ...
in the University of South Carolina. Allen Hermann announced his discovery and the critical temperature
Critical or Critically may refer to:
*Critical, or critical but stable, medical states
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*Critical juncture, a discontinuous change studied in the social sciences.
*Critical Software, a company specializing in ...
of 127 K, in Houston, Texas at the World Congress on Superconductivity organized by Paul Chu in February 1988.
The first series of the Tl-based superconductor containing one Tl–O layer has the general formula TlBa2Ca''n''-1Cu''n''O2''n''+3, whereas the second series containing two Tl–O layers has a formula of Tl2Ba2Ca''n''-1Cu''n''O2''n''+4 with ''n'' =1, 2 and 3. In the structure of Tl2Ba2CuO6 (Tl-2201), there is one CuO2 layer with the stacking sequence (Tl–O) (Tl–O) (Ba–O) (Cu–O) (Ba–O) (Tl–O) (Tl–O). In Tl2Ba2CaCu2O8 (Tl-2212), there are two Cu–O layers with a Ca layer in between. Similar to the Tl2Ba2CuO6 structure, Tl–O layers are present outside the Ba–O layers. In Tl2Ba2Ca2Cu3O10 (Tl-2223), there are three CuO2 layers enclosing Ca layers between each of these. In Tl-based superconductors, ''T''c is found to increase with the increase in CuO2 layers. However, the value of ''T''c decreases after four CuO2 layers in TlBa2Ca''n''-1Cu''n''O2''n''+3, and in the Tl2Ba2Ca''n''-1Cu''n''O2''n''+4 compound, it decreases after three CuO2 layers.
See also
* Cuprate superconductors * Bismuth strontium calcium copper oxide * Yttrium barium copper oxide * Lanthanum barium copper oxideReferences
*''Copper Oxide Superconductors:, by Charles P. Poole, Timir Datta, Horacio A. Farach, John Wiley & Sons, 1988, '' *''Superconductivity: Its historical Roots and Development from Mercury to the Ceramic Oxides, by Per Fridtjof Dahl, AIP, New York, 1st ed. 1992, ''External links
Thallium-based high-temperature superconductors
High-temperature superconductors Thallium compounds Barium compounds Calcium compounds Copper(II) compounds Oxides {{chem-stub