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29 January 2009
Superconductors.ORG
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Signs of superconductivity near 218 Kelvin, reported by
Superconductors.ORG as a minority
phase on November 30, 2008, have now been confirmed. Resistive and diamagnetic
transitions have
been resolved using an established digital summing technique. Those results -
typically 10db over
noise - were then used to contrast samples of different stoichiometry to
identify the probable
structure type.

The material producing the 218K signal appears to have the chemical
formula (Sn5In)
Ba4Ca2Cu11Oy. This conclusion was reached after comparing samples with 10 atoms
of copper per unit
cell to those with 11 atoms of copper per unit cell. In brief, those with 10
copper atoms produced
a strong 212K signal, and a weak 218K. Those samples with 11 copper atoms
produced a strong 218K
signal, and a weak 212K, as seen in the below right plot.

[To read the rest of the article and see the graphics, click the below link.]

http://www.superconductors.org/218K.htm