A New Record Tc of 149 K in HBCCO at Ambient without Pressure by PQP

Pressure can induce various metastable phases to display characteristics important to science and applications. Indeed, the late famed material scientist Pol Duwez pointed out that all solids important to industry are used in their metastable states. Among recent examples are superconductors. All reported superconductivity with a T_c above the liquid nitrogen temperature, other than in cuprates, is achieved under high pressure, which poses a serious barrier to realizing the full potential of superconductivity as envisioned by scientists and engineers for more than a century. One relief to this impasse is to stabilize these metastable phases at ambient pressure. We have therefore developed a pressure-quench protocol (PQP) and have successfully applied it to retain at ambient pressure the pressure-induced superconducting phases in several compounds. In this presentation, we shall discuss the principles and crucial factors for the implementation of the full prowess of PQP for the study of technologically significant solids by showing our results.