Evolution of the spin resonance of CeCoIn$_{5}$ as a function of magnetic field and La substitution

TL;DR

This study investigates how the spin resonance in CeCoIn$_{5}$ changes with magnetic field and La substitution, revealing shifts in energy, broadening, and insights into the magnetic properties of the material.

Contribution

It provides new experimental data on the evolution of spin resonance in CeCoIn$_{5}$ under magnetic field and La doping, highlighting the behavior of resonance energy and lineshape.

Findings

Resonance peak shifts to lower energy with doping and magnetic field.

The ratio $ ext{Ω}_{res}/k_{B}T_{c}$ remains nearly constant with La substitution.

Magnetic field decreases excitation energy faster than $T_{c}(H)$, with Zeeman effect consistent with ground state magnetic moment.

Abstract

We report the evolution of the spin resonance in CeCoIn$_{5}$ as a function of magnetic field and lanthanum substitution. In both cases, the resonance peak position shifts to lower energy and the lineshape broadens. For La doping, it is found that the ratio $\Omega_{res}/k_{B}T_{c}$ is almost constant as a function of $x$. Under magnetic field the decrease of the excitation energy is similar for H// [1,$\bar{1}$,0] and [1,1,1] and faster than the decrease of $T_{c}(H)$. The Zeeman effect found for the field applied along [1,$\bar{1}$,0] corresponds to the ground state magnetic moment.