快猫短视频

Recent claims that a material called LK-99 conducts electricity perfectly at room temperature and pressure have kicked off an incredible flurry of experimental activity. There are several ways to test if something is such a superconductor, however the flurry has yet to find much scientific consensus. Creating pure samples of LK-99 in the lab and determining their quality is also proving difficult.听听

Unlike conventional conductors such as metal wires, superconductors allow electricity to pass through them without any resistance, which means that no energy is lost in the process. This is why using superconductors in the power grid could make it much more energy-efficient. 听

Room-temperature superconductors: Here鈥檚 everything you need to know

Truly convenient materials that can conduct electricity perfectly have long been sought after by researchers, but their history is one of difficult experiments, theoretical puzzles and scientific controversy

Precise measurements of resistivity are paramount for verifying superconductivity. 鈥淲hen superconductivity is claimed in materials where nobody expected it, the very first thing that must be shown is zero resistivity,鈥� says at the University of Maryland.听听

Measurements of resistivity must be done very precisely, making sure that an apparent zero measurement is not a quirk of laboratory equipment or the result of a misinterpreted reading. Currently, four teams have measured the resistivity of LK-99, but only two have found signs of zero resistivity. 听

at the College of William & Mary in Virginia and his colleagues who originally created LK-99 reported a drop to zero resistivity for temperatures ranging from 30掳C (86掳F) to 127掳C (261掳F). While the team of at the University of Nanjing in China found it only dropped to zero at temperatures below -163掳C (-261掳F). 听

In both cases, many commentators said that the drop was not actually to zero but rather to values that seemed close to zero only when compared with the material鈥檚 resistivity at even higher temperatures. 听

There are other properties that a true superconductor should also exhibit, like being able to levitate above a magnet, responding to heat in a particular way 鈥� which is evaluated using a measure called heat capacity 鈥� and restrictions on what energy levels its electrons can inhabit.听

快猫短视频s race to test claimed room-temperature superconductor

Researchers are moving quickly to test if a material called LK-99 really is a superconductor at room temperature and pressure. Several labs have already announced results

Several videos, like from the who has been experimenting in his spare time and , have shown samples of LK-99 partially floating above magnets. But published measurements of how strong this magnetic effect is are sparse, so it isn鈥檛 yet clear whether this magnetic levitation can only be due to superconductivity.听

For Kim, videos of magnetic levitation prove that the 鈥渞eplication problem disappeared鈥�. He blames cases of non-levitating LK-99 samples, like those reported by two independent teams in and , on their poor quality. Researchers are now in a 鈥渃ompetition era鈥� to make more high-quality samples, he says.听听听

Measurements of the other two properties have yet to be publicly reported, save for some heat capacity data in one preprint paper attributed to other LK-99 creators but contested by Kim.听

鈥淣one of it is consistent with each other,鈥� says Das Sarma.听听

An additional problem beyond measuring the superconductivity of LK-99 lies with how it is made to begin with. All the new samples of LK-99 have been made according to Kim鈥檚 team鈥檚 procedure but have relied on X-rays to verify the arrangement of atoms in the material.听听

New superconductor claims could lead to progress even if they鈥檙e wrong

Experts are right to be wary of claims that a room-temperature, ambient-pressure superconductor has been found, but the flurry of new research to confirm the finding could result in a genuine breakthrough

鈥淚t鈥檚 not clear that we know what has been made,鈥� says at the University of Oregon. X-ray imaging only reveals arrangements of atoms within crystalline materials, but the procedure for making LK-99 may also result in some compounds that are not crystalline and would hence not be 鈥渟een鈥� by X-rays, he says. In fact, about the creation of LK-99 noted that only about 50 per cent of each sample was the new material.听

at University College London says the way that the X-ray data comparisons have been done is not ideal either. It is like they 鈥渉eld up the two things, and they looked at one and look to the other and were like, 鈥榶eah, that鈥檚 the same鈥欌��, he says. In his view, replication efforts have not made a strong case that they are testing the same compounds.听

Both Hendon and Palgrave are calling for a detailed analysis of all the chemical elements present in the samples as well as for more rigorous analyses of the X-ray data.听听