Magnetic Excitations in NpCoGa5

TL;DR

This study investigates magnetic excitations in NpCoGa5 using neutron scattering, revealing two energy scales and persistent fluctuations that suggest magnetic fluctuations may play a role in the superconductivity of related materials.

Contribution

It provides the first detailed characterization of magnetic excitations in NpCoGa5, highlighting features relevant to understanding superconductivity in PuCoGa5.

Findings

Two energy scales characterize magnetic response.

Persistent magnetic fluctuations in paramagnetic phase.

Implications for magnetic fluctuations in PuCoGa5 superconductivity.

Abstract

We report the results of inelastic neutron scattering experiments on NpCoGa$_{5}$, an isostructural analogue of the PuCoGa$_{5}$ superconductor. Two energy scales characterize the magnetic response in the antiferromagnetic phase. One is related to a non-dispersive excitation between two crystal field levels. The other at lower energies corresponds to dispersive fluctuations emanating from the magnetic zone center. The fluctuations persist in the paramagnetic phase also, although weaker in intensity. This supports the possibility that magnetic fluctuations are present in PuCoGa$_{5}$, where unconventional d-wave superconductivity is achieved in the absence of magnetic order.