Distinct behaviors of suppression to superconductivity in $LaRu_3Si_2$ induced by Fe and Co dopants

TL;DR

This study investigates how Fe and Co dopants differently affect superconductivity in LaRu$_3$Si$_2$, revealing that Fe induces strong magnetic moments that rapidly suppress superconductivity, unlike Co.

Contribution

The paper demonstrates the contrasting effects of Fe and Co doping on superconductivity in LaRu$_3$Si$_2$, highlighting the role of magnetic moments in suppression mechanisms.

Findings

Fe doping suppresses superconductivity at 3%

Fe impurities create strong magnetic moments

Co doping suppresses superconductivity more gradually

Abstract

In the superconductor LaRu$_3$Si$_2$ with the Kagome lattice of Ru, we have successfully doped the Ru with Fe and Co atoms. Contrasting behaviors of suppression to superconductivity is discovered between the Fe and the Co dopants: Fe-impurities can suppress the superconductivity completely at a doping level of only 3%, while the superconductivity is suppressed slowly with the Co dopants. A systematic magnetization measurements indicate that the doped Fe impurities lead to spin-polarized electrons yielding magnetic moments with the magnitude of 1.6 $\mu_B$\ per Fe, while the electrons given by the Co dopants have the same density of states for spin-up and spin-down leading to much weaker magnetic moments. It is the strong local magnetic moments given by the Fe-dopants that suppress the superconductivity. The band structure calculation further supports this conclusion.