From Ising resonant fluctuations to static uniaxial order in antiferromagnetic and weakly superconducting CeCo(In$_{1-x}$Hg$_{x}$)$_{5}$ ($x$=0.01)

TL;DR

This study investigates how doping CeCoIn5 with Hg transforms its magnetic fluctuations into static uniaxial order, revealing a transition from resonant fluctuations to Ising-type antiferromagnetic order near superconductivity.

Contribution

It demonstrates the emergence of static Ising antiferromagnetic order in Hg-doped CeCoIn5, replacing resonant fluctuations and providing insight into magnetic behavior near superconductivity.

Findings

Resonant magnetic fluctuations are replaced by static Ising order.

No low-energy transverse spin fluctuations are observed in the doped phase.

Static magnetic order is stabilized through Hg doping near superconductivity.

Abstract

CeCo(In$_{0.990}$Hg$_{0.010}$)$_{5}$ is a charge doped variant of the $d$-wave CoCoIn$_{5}$ superconductor with coexistent antiferromagnetic and superconducting transitions occurring at T$_{N}$= 3.4 K and T$_{c}$=1.4 K, respectively. We use neutron diffraction and spectroscopy to show that the magnetic resonant fluctuations present in the parent superconducting phase are replaced by collinear $c$-axis magnetic order with three-dimensional Ising critical fluctuations. No low energy transverse spin fluctuations are observable in this doping-induced antiferromagnetic phase and the dynamic resonant spectral weight predominately shifts to the elastic channel. Static ($\tau$ $>$ 0.2 ns) collinear Ising order is proximate to superconductivity in CeCoIn$_{5}$ and is stabilized through hole doping with Hg.