A paper has appeared that suggests the possibility of room temperature and normal pressure superconductivity in a material similar to LK-99, but the research team is cautious
by Mai-Linh Doan
In July 2023, a South Korean research team published a paper claiming to have confirmed room-temperature and normal-pressure superconductivity in a substance called LK-99, and scientists around the world verified it. As a result, it was concluded that ``LK-99 was not a room temperature and atmospheric pressure superconductor,'' but it is possible that a phenomenon reminiscent of room temperature and atmospheric pressure superconductivity was observed in a sample similar to this LK-99. A paper was published in January 2024. However, the research team is taking a cautious stance and is only suggesting the possibility.
[2401.00999] Possible Meissner effect near room temperature in copper-substituted lead apatite
New research reignites the possibility of LK-99 superconductivity at room temperature — controversial material demonstrates the tell-tale Meissner Effect up to 250 K | Tom's Hardware
https://www.tomshardware.com/tech-industry/superconductors/new-research-reinforces-the-possibility-of-lk-99-room-temperature-superconductivity-controversial-material-demonstrates-the-tell-tale- meissner-effect-up-to-250-k
LK-99 DejaVu? China echoes earlier claim of room temperature superconductors
https://interestingengineering.com/science/lk99-returns-china-echoes-earlier-claim-of-room-temp-superconductors
In July 2023, a Korean research team reported that they had confirmed room-temperature and normal-pressure superconductivity in the synthesized sample 'LK-99.'
A paper and movie that claims to have developed a ``substance that becomes superconducting at room temperature and normal pressure'' will be published - GIGAZINE
Scientists around the world conducted additional tests and verifications on this LK-99. However, many research organizations have stated that they are unable to reproduce LK-99 and that it is theoretically impossible. Nature, the academic journal that published the paper, retracted the paper, and the Korean Society for Superconductivity and Low Temperature Physics also announced that LK-99 was ``baseless.''
Nature retracts a paper on room temperature superconductivity, the second retraction in 1 year and 2 months since a previous paper by the same author was retracted - GIGAZINE
The paper published this time aimed to achieve room-temperature, normal-pressure superconductivity using a material called ``copper-added lead apatite'' like LK-99. The team, led by Professor Yao Yao , a physicist at South China University of Technology, used solid-phase synthesis to synthesize the sample and used electron paramagnetic resonance to determine the magnetic field, as described in the original LK-99 paper. Measuring behavior. In addition, a team led by Professor Wang Hongyang of the Institute of Process Engineering, Chinese Academy of Sciences, synthesized the sample using hydrothermal synthesis and measured the magnetic field with a superconducting quantum interferometer (SQUID).
According to the paper, Professor Wang et al.'s sample synthesis procedure involved co-precipitating phosphate and lead sulfide in an aqueous solution, heating at 180°C under high pressure while maintaining pH 8, and calcining at 900°C for 8 hours under argon. , and then calcined at 500℃ for 48 hours under pure oxygen, and then cooled to room temperature.'' Wang et al.'s sample is unique in that it contains sulfur, unlike LK-99.
As a result, the research team reported that they were able to confirm a phenomenon similar to the Meissner effect at 100K (minus approximately 173 degrees Celsius), 200K (minus approximately 73 degrees Celsius), and 250K (minus approximately 23 degrees Celsius).
The Meissner effect is one of the properties of superconductors, and is a phenomenon in which when a superconductor is placed in a magnetic field, the magnetic field is pushed out of the superconductor. Mr. Yao's team and Mr. Wang's team synthesized the samples using different methods, but they both reported similar research results, so they jointly published a paper.
However, both research teams only maintain that their findings suggest the possibility of the Meissner effect, and are cautious about room-temperature, normal-pressure superconductivity itself. Even if magnetic properties such as repulsion to an external magnetic field are observed, it cannot be determined whether or not this is due to the Meissner effect.
Although room-temperature and normal-pressure superconductivity has been regularly reported, the reproducibility is low, and there has never been a case in which room-temperature-pressure superconductivity has been recognized even after additional tests were conducted by researchers around the world. If room-temperature, normal-pressure superconductivity is realized, there is no doubt that human civilization will achieve a major breakthrough, but careful verification is therefore required. Science media Interesting Engineering said, ``We must be careful not to make big claims without strong evidence to maintain the credibility of science.''
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