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July 10, 2008

YCBO superconductor at 105K and upcoming 195K superconductor

Superconductors.org reports the critical transition temperature (Tc) of the industrial superconductor YBCO (YBa2Cu3O7) has been successfuly increased from 92K to near 105K by reformulating to Y3Ba5Cu8Ox. No new elements were added.

Y-358 - dubbed "Ultra YBCO" - is a novel intergrowth incorporating two different types of planar weight disparity (PWD) and a larger unit cell (around 31.2Ã). The target structure, shown below left, is colinear and does not incorporate branching of the CuO2 chains, as occurs in the Y-124 and Y-247 structure types.

Other YBCO variants have also been discovered by Superconductors.ORG, but had limitations vis-a-vis standard YBCO. "Super YBCO" (Tc up to 107K) required the use of an expensive heavy rare earth oxide to synthesize. And "Enhanced YBCO" (Tc 97K) was not homogenous. Its volume fraction appeared to be around 30%. Ultra YBCO should cost no more than standard YBCO to manufacture.

Synthesis of the material was by the solid state reaction method. Stoichiometric amounts of the below precursors were mixed, pelletized at 70,000 psi and sintered for 11 hours at 890C. The pellet was then annealed for 10 hours at 500C in flowing O2.

Superconductors.org is also teasing that they have a superconductor that works at 195K which is the dry ice sublimation temperature [-78 Celsius which is 195 Kelvin]

So this year has seen excellent experimental progress being made to room temperature (300K) superconductors as well as theoretical progress. There has also been the whole new class of higher temperature iron based superconductors.

1 comments:

Snake Oil Baron said...

Very exciting news. My fingers are crossed for more such breakthroughs. Even a superconductor that required temperatures below freezing but well above dry ice could move all sorts of applications out of university labs and big industry and into far wider spheres of innovation.