Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scattering

TL;DR

This study investigates how magnetic fields influence the spin resonance in FeTe(0.5)Se(0.5) superconductor using inelastic neutron scattering, revealing the resonance's sensitivity to magnetic fields and its link to superconductivity.

Contribution

It provides new insights into the magnetic field effects on spin resonance in Fe-based superconductors, highlighting the relationship between magnetic excitations and superconductivity.

Findings

Resonance appears at ~6 meV below Tc

Magnetic field reduces Tc and resonance intensity

Resonance is sensitive to magnetic field changes

Abstract

Inelastic neutron scattering and susceptibility measurements have been performed on the optimally-doped Fe-based superconductor FeTe(0.5)Se(0.5), which has a critical temperature, Tc of 14 K. The magnetic scattering at the stripe antiferromagnetic wave-vector Q = (0.5,0.5) exhibits a "resonance" at ~ 6 meV, where the scattering intensity increases abruptly when cooled below Tc. In a 7-T magnetic field parallel to the a-b plane, Tc is slightly reduced to ~ 12 K, based on susceptibility measurements. The resonance in the neutron scattering measurements is also affected by the field. The resonance intensity under field cooling starts to rise at a lower temperature ~ 12 K, and the low temperature intensity is also reduced from the zero-field value. Our results provide clear evidence for the intimate relationship between superconductivity and the resonance measured in magnetic excitations of Fe-based superconductors.