Effects of La non-magnetic impurities on the spin resonance of CeCoIn$_{5}$

TL;DR

This study investigates how non-magnetic La impurities affect the spin resonance in CeCoIn$_{5}$, revealing shifts in resonance energy and broadening of excitations, with comparisons to impurity effects in cuprate superconductors.

Contribution

It provides new insights into impurity effects on spin dynamics in heavy fermion superconductors, specifically showing how La substitution alters the spin resonance characteristics.

Findings

Resonance peak shifts to lower energies with La substitution.

Resonance broadens and reaches 0.3 meV at higher impurity levels.

The ratio of resonance energy to T_c remains unchanged.

Abstract

The influence of La non magnetic impurities on the spin dynamics of CeCoIn$_{5}$ was studied by inelastic neutron scattering. In La-substituted systems, the spin resonance peak (observed at $\Omega_{res}=0.55 meV$ in the pure system) is shifted to lower energies but the ratio $\Omega_{res}/k_{B}T_{c}$ remains unchanged. The excitation broadens till it reaches 0.3 meV equal to the value of the quasi-elastic signal in the normal state. The evolution of La substitution is compared with the evolution of the magnetic resonance in Ni and Zn substituted YBa$_{2}$Cu$_{3}$O$_{7}$.