Probing the Meissner effect in single crystals of $\mathbf{B}{\mathbf{i}}_2\mathbf{S}{\mathbf{r}}_2\mathbf{C}{\mathbf{a}}_2\mathbf{C}{\mathbf{u}}_3{\mathbf{O}}_{10+\delta }$ via wide-field quantum microscopy under high pressure

Abstract

We investigated the pressure dependence of the superconducting transition temperature ($T_{\mathrm{c}}$) in optimally doped Bi${}_2$Sr${}_2$Ca${}_2$Cu${}_3$O${}_{10+\delta }$ (Bi-2223) single crystals using different pressure-transmitting media. Previous high-pressure studies have reported conflicting behaviors, ranging from a resurgence of $T_{\mathrm{c}}$ of optimally doped Bi-2223 in fluid media to an insulating-like transition in solid media. However, a direct comparison of the effects of different pressure-transmitting media is lacking. Here, we employed wide-field quantum microscopy based on nitrogen-vacancy centers to probe the magnetic response under high pressure, utilizing cBN and KBr as media. We observed that a diamagnetic response near 70 K, indicative of the superconducting transition, persisted up to 23 GPa in KBr, whereas it disappeared above 11 GPa and 70 K in cBN. These results demonstrate the high sensitivity of Bi-2223 to the pressure environment and highlight the critical role of hydrostatic pressure in cuprate superconductors.