Superconductors.ORG (Joe Eck) reports the 30 Celsius superconductor discovered in December 2012 has been successfully reformulated to advance high Tc to above 35 Celsius (95F, 308K). This was accomplished with a simple substitution of tetravalent silicon into the magnesium atomic sites. The chemical formula thus becomes Tl5Pb2Ba2Si2.5Cu8.5O17+. This is the third material discovered with a critical transition temperature (Tc) above room-temperature.
Joe Eck is a lone researcher who has had some previous work published in smaller journals and some other researchers have copied his work and had them published. He detects magnetic transitions that indicate likely superconductivity but the material has a low percentage of superconducting material and needs to be processed and purified. He has not been able to get the interest or cooperation of larger institutions. Joe has also done work to improve the formulation of YCBO superconducting materials
Multiple magnetization tests were performed on two separate test pellets to confirm this exceptionally high Tc. The highest and lowest measurements on the first sample ranged from 37.1 C to 35.8 C. The second pellet produced diamagnetic transitions between 37.5 C and 35.5 C. The average of all the tests was just under 36 Celsius. The flashing lines in the two plots at page top represent the average of the noise component skewing apart near 36 C in both warming and cooling test cycles
With an ionic radius smaller than magnesium (0.4 Å - vs - 0.72 Å) silicon will occupy the same atomic sites in the "Light" region of the C1 and C2 axes as magnesium does. This is illustrated in the D9223 graphic at left with an arrow pointing to the Si-Cu plane. Though the planar weight ratio is lower with silicon than with magnesium, the Cu02 planes clearly benefit from being electron-doped.
Below is the plot of a second sample pellet, synthesized and tested three days after the first pellet. The plot again shows an unambiguous diamagnetic transition just below 36 C. Resistance tests were not possible with this formulation, as the non-superconductive bulk material is an insulator at room-temperature. A measureable bulk resistance is required to observe a resistance change resulting from a minority phase.
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