Superconductivity Locked at 151 K: Researchers Fix High-Tc State After Pressure Release

A team of researchers from Argonne National Laboratory and the University of Houston has developed a method to lock in superconducting properties of a material after removing the extreme pressure that originally enabled them. The findings were published in PNAS Physics.

The study focused on a cuprate compound, HgBa2Ca2Cu3O8+δ — known as Hg1223 or part of the HBCCO series. This material has been studied since the 1990s and exhibits a transition temperature (Tc) of 133 K (-140 °C) under ambient pressure. To achieve superconductivity at room temperature, these materials typically require crushing pressures that would destroy any biological structure.

The researchers applied a pressure-quench protocol (PQP). They cooled the sample under high pressure and then suddenly released that pressure while maintaining the low temperature. This process raised the Tc to 151 K (-122 °C) — an increase of 18 K over the original value. Crucially, the superconducting properties persisted after the pressure was fully removed, indicating that the high-pressure state had been "frozen" into the material.

While 151 K is still far from room temperature, the ability to raise the critical temperature by 18 K through a relatively simple procedure is significant. It suggests that the cooling requirements for superconductors could be substantially reduced if similar techniques are applied to other materials. This could make superconductors more practical for applications in power transmission, magnetic levitation, and medical imaging, where current cooling costs are a major barrier. The research also provides new insights into how pressure-induced structural changes can be preserved in cuprate superconductors.