Superconductors could revolutionize our world. Transmitting electricity without resistance is already a phenomenal advantage and that, along with their peculiar quantum properties, makes superconductors key for many technological leaps. The only problem is that materials are only superconducting at very low temperatures.
A few new studies have come out recently announcing that the goal of a room-temperature superconductor is getting closer. In a paper released on the preprint server arXiv, researchers discuss observations of a particular material being superconductive at -23°C (-9.4°F). If the work is confirmed, this would be a jump of about 50 degrees from the previous record.
There are usually three tests to confirm that a material is superconductive. First, it obviously needs to show zero electrical resistance. Second, it needs to have the isotope effect, where by switching to heavier isotopes the critical superconducting temperature becomes lower. The third is the Meissner effect, where a magnetic field is expelled by the superconducting material. That’s the reason why you get hoverboards that use superconductors.
The material tested is a hydride of lanthanum, an atom of the silvery metal surrounded by 10 hydrogen atoms. It passed the first two tests but the sample obtained was too small to perform the third one. The researchers conducted another magnetic test with very positive results.
The reason behind the limited sample size is one of the catches of this approach. The material needs to be kept at the incredible pressure of 1.6 million atmospheres, slightly less than half the pressure one would find at the center of the Earth. The researchers squeezed the sample between two diamond anvils and observed its exceptional properties.
The team focused on hydride of lanthanum and other hydrides because calculations showed that their superconducting range under high pressure could be as high as 70°C (158°F). The starting point of this study was actually the work of a different group looking into the same material. They announced superconductivity at 7°C (44.6°F). While that wasn’t observed in this study, a superconducting material that would work in a regular freezer is still a huge leap forward.
Understanding what makes room-temperature superconducting materials tick, even if under these high pressures, could be crucial to developing ones that can be used in everyday conditions.