Physicists claim to have achieved superconductivity at the highest temperature ever recorded

Scientists in Germany say they have hit a new superconductivity milestone. According to their paper, they achieved resistance-free electrical current at the highest temperature yet: just 250 Kelvin, or -23°C.

Although the team's superconducting material has yet to be verified, the work was led by Mikhail Eremets from the Max Planck Institute for Chemistry, who set the previous high temperature record for superconductivity in 2014, at 203 Kelvin (-70°C).

If superconductivity could be achieved above 0°C, it would revolutionise electrical efficiency, vastly improving power grids, high-speed data transfer, and electrical motors, to name a few potential applications.

It's something that many laboratories around the world have been working on, with claims of high-temperature superconductivity appearing from time to time only to fail reproducibility tests.

Eremets and his team achieved the previous high-temperature superconductivity record using hydrogen sulphide under 150 gigapascals of pressure (Earth's core is between 330 and 360 gigapascals).

Scientists who believe that this result was possible because hydrogen sulphide is so light that it can vibrate at high speeds, which means higher temperatures – but the pressure is needed to keep it from vibrating itself apart.

This new research used a different material, called lanthanum hydride, under about 170 gigapascals of pressure.

In their paper, the scientists said: “This leap, by 50 Kelvin, from the previous critical temperature record of 203 Kelvin indicates the real possibility of achieving room-temperature superconductivity in the near future at high pressures, and the perspective of conventional superconductivity at ambient pressure.”

The result is yet to be verified by the scientific community, and the paper is awaiting peer-review.

The team has, so far, achieved two of the three tests that are considered ‘gold standard’ for superconductivity: the drop in resistance below a critical temperature threshold, and replacing elements in the material with heavier isotopes to observe a corresponding drop in superconductivity temperature.

The third is the Meissner effect, which is the name given to one of the signatures of superconductivity. As the material passes below the critical temperature and transitions into superconductivity, it ejects its magnetic field.

The team has yet to observe this phenomenon because their sample is so small – well below the detection capabilities of a magnetometer. However, the transition into superconductivity effects the external magnetic field, too. It's not a direct detection, but the team claims it has observed this effect meaning that other scientists with stronger magnetometers could theoretically test the Meissner effect.