Superconducting Properties of La$_2$(Cu$_{1-x}$Ni_x)$_5$As$_3$O$_2$: A $\rm \mu$SR Study

TL;DR

This study investigates the superconducting properties of La$_2$(Cu$_{1-x}$Ni$_x$)$_5$As$_3$O$_2$ using muon spin rotation, revealing a two-band superfluid density, specific penetration depths, and no TRS breaking, contributing to understanding layered Cu-based superconductors.

Contribution

First muon spin rotation study on La$_2$(Cu$_{1-x}$Ni$_x$)$_5$As$_3$O$_2$, demonstrating two-band superconductivity and absence of TRS breaking.

Findings

Superfluid density follows a two-band model.

Zero-temperature penetration depth is around 420 nm.

No evidence of time-reversal symmetry breaking.

Abstract

We report the results of muon spin rotation and relaxation ($\rm \mu$SR) measurements on the recently discovered layered Cu-based superconducting material La$_{2}($Cu$_{1-x}$Ni$_{x}$)$_{5}$As$_{3}$O$_{2}$ ($x =$ 0.40, 0.45). Transverse-field $\rm \mu$SR experiments on both samples show that the temperature dependence of superfluid density is best described by a two-band model. The absolute values of zero-temperature magnetic penetration depth $\lambda_{\rm ab}(0)$ were found to be 427(1.7) nm and 422(1.5) nm for $x =$ 0.40 and 0.45, respectively. Both compounds are located between the unconventional and the standard BCS superconductors in the Uemura plot. No evidence of time-reversal symmetry (TRS) breaking in the superconducting state is suggested by zero-field $\rm \mu$SR measurements.