High-pressure effects in fluorinated HgBa2Ca2Cu 3O8+δ

Abstract

We have measured the pressure sensitivity of Tc in fluorinated HgBa2Ca2Cu3O8+δ (Hg-1223) ceramic samples with different F contents, applying pressures up to 30GPa. We obtained that Tc increases with increasing pressure, reaching different maximum values, depending on the F doping level, and decreases for a further increase of pressure. A new high Tc record (166 K±1 K) was achieved by applying pressure (23GPa) in a fluorinated Hg-1223 sample near the optimum doping level. Our results show that all our samples are at the optimal doping, and that fluorine incorporation decreases the crystallographic a-parameter concomitantly increasing the maximum attainable Tc. This effect reveals that the compression of the a-axis is one of the keys that controls the Tc of high-temperature superconductors. © EDP Sciences.