Effect of pressure on the superconducting critical temperature of La[O_{0.89}F_{0.11}]FeAs and Ce[O_{0.88}F_{0.12}]FeAs

TL;DR

This study investigates how applying high pressure affects the superconducting transition temperatures of La[O_{0.89}F_{0.11}]FeAs and Ce[O_{0.88}F_{0.12}]FeAs, revealing different pressure dependencies for each material.

Contribution

It provides the first detailed high-pressure resistivity data on these iron-based superconductors, showing contrasting T_c behaviors under pressure.

Findings

La-based compound's T_c peaks between 10-68 kbar

Ce-based compound's T_c decreases monotonically with pressure

Ce compound's T_c drops below 1.1 K at 265 kbar

Abstract

We have performed several high-pressure resistivity experiments on the recently discovered superconductors La[O_{0.89}F_{0.11}]FeAs and Ce[O_{0.88}F_{0.12}]FeAs. At ambient pressure, these materials have superconducting onset temperatures T_c of 28 K and 44 K, respectively. While the T_c of La[O_{0.89}F_{0.11}]FeAs goes through a maximum between 10-68 kbar, in qualitative agreement with a recent report by Takahashi et al., the T_c of Ce[O_{0.88}F_{0.12}]FeAs decreases monotonically over the measured pressure range. At 265 kbar, the T_c of the cerium-based compound has been suppressed below 1.1 K.