Don’t celebrate too quickly. We are still a long way from proving room-temperature superconductivity.

Too long to read version:

The successful reproduction of magnetic levitation can only prove that LK-99 has a certain degree of diamagnetism, but it cannot prove that it has the complete diamagnetism unique to superconductors;

Whether LK-99 is a room-temperature superconductor depends on whether subsequent measurements show zero resistance.

Ever since a South Korean team published a paper on arXiv claiming to have discovered the normal-pressure room-temperature superconductor LK-99, the world seems to have been swept up in a craze for preparing materials and reproducing experiments.

Apart from other things, there are more than one company that live-streamed the "alchemy" reproduction experiment on Bilibili alone, and those that live-streamed it with pictures and text on other social media such as X also received a large amount of traffic.

Bilibili is broadcasting a live broadcast channel that reproduces room temperature superconductivity | Bilibili screenshot

However, just today, at 15:08:16 Beijing time, a major breakthrough was revealed on Bilibili - the up master "Guanshankou Male Technician" released a video showing that the LK-99 sample they prepared can achieve magnetic levitation at room temperature.

As of 10 p.m. tonight, this video, which is less than 4 minutes long, has been played more than 3.3 million times on Bilibili.

The red arrow points to the sample, and the upper left is a toothpick | Screenshot of the video of the B station up master "Guanshankou Male Technician"

The video shows a needle-tip-sized sample. After placing a neodymium iron boron magnet underneath it, one end of the sample sticks to the bottom surface while the other end rises spontaneously. The lifting angle reaches almost 90 degrees, which is a larger suspension angle than the video previously released by the Korean team.

"Guanshankou Male Technician" wrote in the video description: "Under the guidance of Professor Chang Haixin, postdoctoral fellow Wu Hao and doctoral student Yang Li from the School of Materials Science and Engineering of Huazhong University of Science and Technology successfully verified the synthesis of LK-99 crystals that can be levitated for the first time. The levitation angle of the crystal is larger than that of the sample obtained by Sukbae Lee and others, and it is expected to achieve true contactless superconducting magnetic levitation."

It can be said that Huazhong University of Science and Technology is the first unit in the world to publicly announce the successful reproduction of the LK-99 magnetic levitation experiment.

However, don't be too happy too soon.

The successful reproduction of magnetic levitation can only prove that LK-99 has anti-magnetism, that is, there is a repulsive force between it and the magnet, but it cannot prove that it has the room-temperature superconducting characteristics claimed by the Korean team. The so-called complete anti-magnetism is only a necessary condition for superconductors, but not a sufficient condition.

Two hours after publishing the magnetic levitation video, the B station up master "Guanshankou Male Technician" released another supplementary video. In the new video, the magnet was placed above the sample, and no obvious reaction was seen in the sample.

If the sample is completely diamagnetic, the magnet will have an attractive effect on the sample under certain conditions, which is not reflected at all in the supplementary video.

Of course, due to factors such as sample purity and observation method, we cannot conclude that LK-99 is not completely anti-magnetic.

To verify whether LK-99 is a room-temperature superconductor, the most critical thing is to measure whether the sample exhibits zero resistance characteristics.

Unfortunately, due to sample conditions, the sample that reproduced magnetic levitation cannot be used to measure resistance. The laboratory of Huazhong University is preparing a new batch of samples, hoping to further measure the resistance characteristics of LK-99.

Up master "Guanshankou Male Technician" explained the reason why resistance cannot be measured in the comment of B station | Screenshot of B station

Coincidentally, the Zhihu answerer "Semiconductors and Physics" also successfully reproduced the magnetic levitation of the LK-99 sample today. The video he published at 20:19 tonight is similar to the results of Huazhong University of Science and Technology. The sample size is very small, and a magnet is placed underneath, and one end of the sample also appears to be lifted.

Although the experimental results of reproducing magnetic levitation cannot prove that LK-99 is a room-temperature superconductor, it at least shows that the Korean team's papers and videos are most likely not fabricated out of thin air.

This undoubtedly provides a positive signal for researchers who are trying to study and reproduce the results of related papers.

Prior to this, researchers from the National Physical Laboratory of India and the Beijing University of Aeronautics and Astronautics had published papers on arXiv, claiming to have successfully prepared the LK-99 material and provided X-ray diffractometer analysis results to prove this, but they did not observe the phenomenon of magnetic levitation and zero resistance in the samples.

Professor Sun Yue of Southeast University also published a video on Bilibili, detailing the entire experimental process from preparing LK-99 to verifying its properties. The final sample did not show any obvious reaction when placed on a magnet, and the magnetization measurement results did not show any signs of superconductivity.

Indian Results | References [6]

Beihang University Results | References [5]

Southeast University Results | References [3]

Why are only a few researchers at Huazhong University of Science and Technology able to reproduce the magnetic levitation phenomenon of LK-99? The reason is probably the sample itself.

Although the Korean team announced their process of preparing LK-99, the samples prepared by different research teams are likely to vary due to factors such as the preparation process and sample purity, and even small structural differences may lead to very different properties of the material.

Regarding the preparation of LK-99, Hyun-Tak Kim, one of the authors of the paper published by the Korean team and a professor in the Department of Physics at the College of William and Mary in the United States, said in response to a request for comment from a reporter from the Daily Economic News that the LK-99 room-temperature superconducting material made by his team could perhaps be replicated within one month, and that its members would also provide guidance on the production method of LK-99. The purpose of disclosing the production method of LK-99 in the article was also to accept questions from all parties.

In summary, based on the current experimental results, LK-99 may be a type of material with antimagnetic properties, but it is far from concluding that it is a room-temperature superconductor as claimed by the Korean team. Its specific properties still need more subsequent experimental verification.

So, don't be impatient, just let the bullet fly a little longer.

Although the bullet has been flying for a while, it is still a long way from our target - it may even be flying in the wrong direction...

References

[1] www.bilibili.com/video/BV14p4y1V7kS/

[2] www.bilibili.com/video/BV13k4y1G7i1/

[3] www.bilibili.com/video/BV1yj41167Xd/

[4] www.zhihu.com/question/613850973/answer/3136586869

[5] arxiv.org/ftp/arxiv/papers/2307/2307.16802.pd

[6] arxiv.org/ftp/arxiv/papers/2307/2307.16402.pdf

Planning and production

Source: Guokr (ID: Guokr42). No secondary reproduction is allowed without authorization. If you have any questions, please contact [email protected]

Author: Neutron Star Science Creator