【速報】先週の常圧室温超伝導、否定的な追試結果が報告される
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The quest for room-temperature superconductors has been teasing scientists and physicists, since its inception in 1911 itself.
Several assertions have already been made about room temperature superconductivity but were never verified or reproduced across the labs.
The cuprates were the earliest high transition temperature superconductors, and it seems that copper has done the magic once again.
Last week, a Korean group synthesized a Lead Apatite-based compound LK-99, showing a Tc of above 400∘K.
The signatures of superconductivity in the compound are very promising, in terms of resistivity (R = 0) and diamagnetism at Tc.
Although, the heat capacity (Cp) did not show the obvious transition at Tc.
Inspired by the interesting claims of above room temperature superconductivity in LK-99, in this article, we report the synthesis of polycrystalline samples of LK-99, by following the same heat treatment as reported in [1,2] by the two-step precursor method.
The phase is confirmed through X-ray diffraction (XRD) measurements, performed after each heat treatment.
The room temperature diamagnetism is not evidenced by the levitation of a permanent magnet over the sample or vice versa.
Further measurements for the confirmation of bulk superconductivity on variously synthesized samples are underway.
Our results on the present LK-99 sample, being synthesized at 925∘C, as of now do not approve the appearance of bulk superconductivity at room temperature.
Further studies with different heat treatments are though, yet underway.
Synthesis of possible room temperature superconductor LK-99:Pb9Cu(PO4)6O
https://arxiv.org/abs/2307.16402 追試なんかしなくても嘘に決まってるだろ
チョン理論なんだから 超伝導についてよく分かんないけど
熱容量が変化しないから違うっぽいってこと？ 別のグループによって同日報告された追試結果でも電気抵抗について否定的な結果が得られた模様
Semiconducting transport in Pb10-xCux(PO4)6O sintered from Pb2SO5 and Cu3P
https://arxiv.org/abs/2307.16802
The very recent claim on the discovery of ambient-pressure room-temperature superconductivity in modified lead-apatite has immediately excited sensational attention in the entire society, which is fabricated by sintering lanarkite (Pb2SO5) and copper(I) phosphide (Cu3P).
To verify this exciting claim, we have successfully synthesized Pb2SO5, Cu3P, and finally the modified lead-apatite Pb10-xCux(PO4)6O.
Detailed electrical transport and magnetic properties of these compounds were systematically analyzed.
It turns out that Pb2SO5 is a highly insulating diamagnet with a room-temperature resistivity of ~7.18x10^9 this http URL and Cu3P is a paramagnetic metal with a room-temperature resistivity of ~5.22x10^-4 this http URL.
In contrast to the claimed superconductivity, the resulting Pb10-xCux(PO4)6O compound sintered from Pb2SO5 and Cu3P exhibits semiconductor-like transport behavior with a large room-temperature resistivity of ~1.94x10^4 this http URL although our compound shows greatly consistent x-ray diffraction spectrum with the previously reported structure data.
In addition, when a pressed Pb10-xCux(PO4)6O pellet is located on top of a commercial Nd2Fe14B magnet at room temperature, no repulsion could be felt and no magnetic levitation was observed either.
These results imply that the claim of a room-temperature superconductor in modified lead-apatite may need more careful re-examination, especially for the electrical transport properties. >>8
>>1は比熱は測定してない
先週の報告で既に比熱の測定結果も報告されてたが，超伝導転移に伴う異常は見られていなかった ■ このスレッドは過去ログ倉庫に格納されています
