Nonmonotonic Pressure Dependence of the Lattice Parameter $a$ in the Quasi-one-dimensional Superconductor Pr$_2$Ba$_4$Cu$_7$O$_{15-\delta}$

TL;DR

This study reveals a nonmonotonic pressure dependence of the lattice parameter in a quasi-one-dimensional superconductor, indicating a maximum inter-chain interaction at around 2.0 GPa, supported by resistance measurements under magnetic fields.

Contribution

It reports the unusual pressure behavior of lattice parameter $a$ and links it to changes in dimensionality in Pr$_2$Ba$_4$Cu$_7$O$_{15-eta}$, combining structural and magneto-transport data.

Findings

Lattice parameter $a$ increases with pressure starting at 2.0 GPa.

Maximum inter-chain interaction occurs near 2.0 GPa.

Magneto-resistance measurements suggest a dimensional crossover.

Abstract

In the quasi-one-dimensional superconductor, Pr$_2$Ba$_4$Cu$_7$O$_{15-\delta}$, we found that the lattice parameter, $a$ increased against pressure, starting at 2.0 GPa at approximately 300 K. This result suggests that the two-dimensional inter-conducting-chain interaction along the $a$ axis is most enhanced at approximately 2.0 GPa. To discuss the dimensionality, we also measured the resistance under magnetic fields up to 14 T, because magneto-resistance is induced when a system changes from one-dimensional to two-dimensional.