Evolution of the spin resonance in CeCoIn$_5$ under magnetic field

TL;DR

This study investigates how the magnetic excitation spectrum, particularly the spin resonance, in CeCoIn$_5$ evolves under an external magnetic field, revealing changes in energy, broadening, and persistence up to half the upper critical field.

Contribution

It provides new insights into the behavior of the spin resonance in CeCoIn$_5$ under magnetic fields using inelastic neutron scattering, highlighting its persistence and evolution.

Findings

Spin resonance persists up to about half of Hc2

Resonance energy decreases with increasing magnetic field

Lineshape of resonance broadens significantly

Abstract

The evolution of the magnetic excitation spectrum of the unconventional superconductor CeCoIn$_{5}$ was studied by inelastic neutron scattering as a function of magnetic field applied in the [1, -1, 0] direction. The spin resonance characteristic of the superconducting states was observed up to about $H_{c2}$/2 : it is still centered at (1/2, 1/2, 1/2) when the magnetic field increases while its characteristic energy decreases and its lineshape substantially broadens.