Reversible magnetization and superconducting properties of the four-layered Ba2Ca3Cu4O8+y(F,O)2Ba2Ca3Cu4O8+y(F,O)2 superconductor with Tc∼90.6K

Reversible magnetization of grain-aligned Ba2Ca3Cu4O8+y(F,O)2Ba2Ca3Cu4O8+y(F,O)2 (F-0234) with Tc≃90.6K, which is a member with n  =4 in the new homologous series Ba2Can−1CunO2n(F,O)2Ba2Can−1CunO2n(F,O)2 was investigated using the Hao–Clem model and fluctuation theories. The almost temperature independence of the Ginzburg–Landau parameter (κκ) up to 0.9 T/TcT/Tc and the crossover point in M(T) indicated less 2D character, suggesting no drastic decrease in interlayer coupling compared to other high-Tc cuprate superconductors. The relatively strong interlayer coupling results from the smallest thickness of the charge reservoir block among other multilayered systems. On the other hand, the λab(0)λab(0) and Hc(0)Hc(0) values derived from the Hao–Clem analysis strongly suggest that the decrease in Tc is due to both the decrease in the carrier density and weakened pairing strength.

► Superconducting parameters of F-0234 superconductors were obtained.
► Our results suggest less 2D character of F-0234.
► The relatively lower Tc is due to less carrier density and weakened pairing strength.