Slashdot Mirror
New Superconductor World Record Surpasses 250K
myrrdyn writes to tell us that a new superconductivity record high of 254 Kelvin (-19C, -2F) has been recorded. According to the article this is the first time a superconductive state has been observed at a temperature comparable to a household freezer. "This achievement was accomplished by combining two previously successful structure types: the upper part of a 9212/2212C and the lower part of a 1223. The chemical elements remain the same as those used in the 242K material announced in May 2009. The host compound has the formula (Tl4Ba)Ba2Ca2Cu7Oy and is believed to attain 254K superconductivity when a 9223 structure forms"
From TFA:
This discovery is being released into the public domain without patent protection in order to encourage additional research.
Amazingly cool. (No pun intended.)
...it is a ceramic, which can hardly be used as a cable conductor.
You mean except for the ceramic cables that are already in use? I think your "information" may be a wee bit out of date.
What is "the upper part of a 9212/2212C and the lower part of a 1223?"
9212/2212C and 1223 are structure names. Would you like an introductory crystallography text with your summary next time? It would, after all, save you the onerous effort of following the article link.
And I don't believe there's an element known as Oy.
O-sub-y, indicating an indefinite ratio of oxygen.
I agree. No mention of a paper, or any corroboration. Is this guy ( http://setiathome.berkeley.edu/view_profile.php?userid=4422 ) claiming that he's discovered it? By the way, comedy quote from that page:
"I think there is a strong possibility of extraterrestrial life based on a passage in the Bible. The Lord talks about gathering His creation from the ends of the Universe."
Sigh... I know this is Slashdot, but how about reaching as far as your keyboard and throwing a few obvious keywords at Google?
From en.wikipedia.org/wiki/Electric_power_transmission:
"Transmission and distribution losses in the USA were estimated at 7.2% in 1995"
Re-sigh.
My PhD thesis was on studies of these materials. Some things the guy says make it sound like he has some bit of a clue (like the fact that such materials are indeed very sensitive to water). other things he says make him a crackpot (his webpage for instance says: "Since outer space is full of superconducting elements and compounds, I think they could help explain the increasing expansion rate of the universe (through strong diamagnetism).").
Making high purity materials like these takes big expensive furnaces and people who know how to use them (very few in the entire world). The method he describes is unsuitable for making decent single crystals and so his samples will not yield much meaningful bulk information. Working with stuff like Tl is tough because it is so toxic and so making these crystals is doubly difficult, especially in the US with so many safety regulations. Just on that basis alone, it is hard to believe he has the material he says he does. When he says "The volume fraction of this material is very low." it is a huge red flag that he knows not what his sample is. The research community has been all about getting purity up over the last couple of decades and many results with less pure samples did not hold up to these refinements.
As far as physics goes, there is much research out there suggesting that some superconductivity survives in established cuprates above bulk T_c. Even besides that, the electronic states in these materials above T_c are screwed up. My research showed some very interesting electronic phases directly. Thus, a small jump in a poorly evaluated variable may be there but cannot necessarily be taken seriously as an indication of bulk superconducting order even if it is measured carefully.
On top of which, his graphs are your typical crank type graphs. What am I supposed to conclude from voltage vs. temperature? How is that related to resistivity? What are the units? If the material is just synthesized, then how is crystal structure already known? Which beamline was used?
In short, wake me up when one of three or four reputable sample growers (BSCCO crystals are mostly grown in Japan btw, and Tl stuff used to be grown in Russia a lot, from what I heard because of lack of safety oversight there) makes a good crystal and shows something interesting going on.