Evidence for Coexistence of Bulk Superconductivity and Itinerant Antiferromagnetism in the Heavy Fermion System CeCo(In$_{1-x}$Cd$_x$)$_5$

TL;DR

This study demonstrates the coexistence of bulk superconductivity and itinerant antiferromagnetism in CeCo(In$_{1-x}$Cd$_x$)$_5$, revealing how electronic structure modifications influence their interplay under pressure.

Contribution

It provides experimental evidence for the coexistence of superconductivity and itinerant antiferromagnetism in a heavy fermion system using multiple advanced techniques.

Findings

Magnetic order of itinerant character coexists with superconductivity.

Suppression of antiferromagnetism linked to changes in bandwidth and carrier concentration.

Electronic structure modifications under pressure affect the interplay between magnetism and superconductivity.

Abstract

In the generic phase diagram of heavy fermion systems, tuning an external parameter such as hydrostatic or chemical pressure modifies the superconducting transition temperature. The superconducting phase forms a dome in the temperature-tuning parameter phase diagram, which is associated with a maximum of the superconducting pairing interaction. Proximity to antiferromagnetism suggests a relation between the disappearance of antiferromagnetic order and superconductivity. We combine muon spin rotation, neutron scattering, and x-ray absorption spectroscopy techniques to gain access to the magnetic and electronic structure of CeCo(In$_{1-x}$Cd$_x$)$_5$ at different time scales. Different magnetic structures are obtained that indicate a magnetic order of itinerant character, coexisting with bulk superconductivity. The suppression of the antiferromagnetic order appears to be driven by a modification of the bandwidth/carrier concentration, implying that the electronic structure and consequently the interplay of superconductivity and magnetism is strongly affected by hydrostatic and chemical pressure.