Hall effect measurements under high pressure for Pr₂Ba₄Cu₇O_15-δsupercondcutor

It is well known that the Pr-substitution for Y-site in YBa₂Cu₃O_7-δ and YBa₂Cu₄O₈ dramatically suppresses the superconducting transition temperature T_c and superconductivity in CuO₂ planes disappears. However, Pr₂Ba₄Cu₇O_15-δ (Pr247) oxide shows superconductivity with T_c = 15 K after reduction treatment [1]. Pr247 has the same crystal structure as Y₂Ba₄Cu₇O_15-δ with an alternative repetition of the single and double chains along the c-axis. As-sintered sample of Pr247 shows metallic conductivity at low temperatures owing to the conduction in the CuO double chains. Reduction treatment on Pr247 caused the electron carrier density change by controlling the amount of oxygen deficiency. Applying high pressure on superconductive Pr247 suppresses the superconductivity. This is well explained by the one-dimensional conduction mechanism based on Tomonaga-Luttinger liquid theory [2]. High pressure study on Hall effect reveals the effect of pressure on electron carrier concentration for Pr247.
[1]Matsukawa et al., Physica C 411(2004)101, Yamada and Matsushita, Physica C 426(2005)213. [2]Sano et al., J. Phys. Soc. Jpn. 74(2005) 2885