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New Evidence of Superconductivity at Near Room Temperature

posted by chromas on Wednesday January 16 2019, @07:07PM   
from the and-2-million-atmospheres dept.

Arthur T Knackerbracket has found the following story:

The key to this discovery was creation of a metallic, hydrogen-rich compound at very high pressures: roughly 2 million atmospheres. The researchers used diamond anvil cells, devices used to create high pressures, to squeeze together miniscule samples of lanthanum and hydrogen. They then heated the samples and observed major changes in structure. This resulted in a new structure, LaH10, which the researchers previously predicted would be a superconductor at high temperatures.

While keeping the sample at high pressures, the team observed reproducible change in electrical properties. They measured significant drops in resistivity when the sample cooled below 260 K (minus 13 C, or 8 F) at 180-200 gigapascals of pressure, presenting evidence of superconductivity at near-room temperature. In subsequent experiments, the researchers saw the transition occurring at even higher temperatures, up to 280 K. Throughout the experiments, the researchers also used X-ray diffraction to observe the same phenomenon. This was done through a synchrotron beamline of the Advanced Photon Source at Argonne National Laboratory in Argonne, Illinois.

 

Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures^$ (DOI: 10.1103/PhysRevLett.122.027001)

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Original Submission

• Re:180 gigapascals harder to do than liquid N? Re:180 gigapascals harder to do than liquid N? (Score: 2) by FatPhil on Wednesday January 16 2019, @09:13PM (4 children)

  by FatPhil (863) <reversethis-{if.fdsa} {ta} {tnelyos-cp}> on Wednesday January 16 2019, @09:13PM (#787570) Homepage

  The best thing about this is that there seem to be rivals, and they're having a race. The previous record, with the same material, was set by a different team: https://arxiv.org/abs/1812.01561 . Like evolution, science progresses quickest when there's competitive pressure. Apparently models show that yttrium superhydrides, or some shit like that, should out-perform lanthanum varieties, so perhaps room temperature for a more comfortable part of the world will eventually be reached. Then again, they're not 100% sure superconductivity was reached, I believe, as they are presently unable to measure the expulsion of a magnetic field in such a small and inconvenient sample.

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• Re:180 gigapascals harder to do than liquid N? Re:180 gigapascals harder to do than liquid N? (Score: 2) by opinionated_science on Wednesday January 16 2019, @11:30PM (3 children)

  by opinionated_science (4031) on Wednesday January 16 2019, @11:30PM (#787652)

  random thought - what value of acceleration due to gravity on a planet or other celestial body would yield this pressure?

  It occurs if chemistry and high pressure is needed, it may occur naturally - although we may never observe the structure!!

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  • Re:180 gigapascals harder to do than liquid N? Re:180 gigapascals harder to do than liquid N? (Score: 2) by FatPhil on Thursday January 17 2019, @01:22PM (2 children)

    by FatPhil (863) <reversethis-{if.fdsa} {ta} {tnelyos-cp}> on Thursday January 17 2019, @01:22PM (#787880) Homepage

    Not quite answering your question, but it's about the pressure at the centre of the earth. So "in" rather than "on".

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    • Re:180 gigapascals harder to do than liquid N? Re:180 gigapascals harder to do than liquid N? (Score: 2) by opinionated_science on Thursday January 17 2019, @02:03PM (1 child)

      by opinionated_science (4031) on Thursday January 17 2019, @02:03PM (#787886)

      's ok that's what I was driving at - "could there be a natural phenomenon that happens to exploit, as yet undiscovered, high-temp superconductors?"

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      • Re:180 gigapascals harder to do than liquid N? (Score: 0) by Anonymous Coward on Friday January 18 2019, @10:16AM

        by Anonymous Coward on Friday January 18 2019, @10:16AM (#788187)

        The issue is, how to dissipate the heat from the compression? To compress the sample using gravity, requires large planetary mass around it. Makes cooling (and else) impractical.

        We don't know of any nongravitational natural process able to sustain such pressures.

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