Effects of In-Plane Impurity Substitution in Sr2RuO4

TL;DR

This study investigates how nonmagnetic Ti and magnetic Ir impurities affect superconductivity in Sr2RuO4, revealing high sensitivity to impurities and strong scattering effects similar to high-Tc cuprates.

Contribution

It provides the first comparative analysis of nonmagnetic and magnetic impurity effects on Sr2RuO4's superconductivity, highlighting their role as strong potential scatterers.

Findings

Superconductivity is suppressed at ~0.15% impurity concentration.

Residual resistivity increases rapidly, consistent with unitarity-limit scattering.

Both impurities act as strong potential scatterers, akin to Zn in cuprates.

Abstract

We report comparative substitution effects of nonmagnetic Ti^(4+) and magnetic Ir^(4+) impurities for Ru^(4+) in the spin-triplet superconductor Sr2RuO4. We found that both impurities suppress the superconductivity completely at a concentration of approximately 0.15%, reflecting the high sensitivity to translational symmetry breaking in Sr2RuO4. In addition, a rapid enhancement of residual resistivity is in quantitative agreement with unitarity-limit scattering. Our result suggests that both nonmagnetic and magnetic impurities in Sr2RuO4 act as strong potential scatterers, similar to the nonmagnetic Zn^(2+) impurity in the high-Tc cuprates.