For more than thirty years, one number stayed unchanged in physics: 133. This was the highest temperature in Kelvin at which a material could carry electricity with zero resistance at normal pressure. The record was set in 1993 by a mercury-based ceramic, and no one had moved it until now.
Two physicists at the University of Houston have finally broken it. Ching-Wu Chu and Liangzi Deng reported reaching a superconducting temperature of 151 K, or about -122 degrees Celsius, at normal pressure. This is the highest temperature ever recorded since superconductivity was first discovered in 1911.
Why does this matter? Superconductors carry electricity perfectly with no energy lost as heat when cooled below a certain temperature. Today's power grids waste about 8 percent of electricity. A superconducting grid would lose none of it.
The challenge has always been that some materials only work under enormous pressure. The Houston team used a technique called pressure quenching: they applied intense pressure, cooled the material, then released the pressure quickly to lock in the improvement.
The material is a mercury-based ceramic similar to the 1993 record holder. Chu discovered another important compound, YBCO, in 1987. He is now a professor at the University of Houston's Texas Center for Superconductivity.
However, the improved state is not permanent, lasting only about three days. The result also needs confirmation from other laboratories. The true goal remains a superconductor that works at room temperature, but this discovery marks important progress.