Neutron-scattering study of the magnetic response in the heavy-fermion superconductor UNi 2 Al 3

High-resolution neutron inelastic scattering has been used to probe the magnetic response in the heavy-fermion superconductor ${\mathrm{UNi}}_{2}{\mathrm{Al}}_{3}.$ Quasielastic scattering has been observed both below and above ${T}_{c}$ in the vicinity of the incommensurate magnetic ordering vector ${\mathbf{Q}}_{0}=(0.39,0,0.5).$ Features in the response are similar to those reported recently for the isostructural compound ${\mathrm{UPd}}_{2}{\mathrm{Al}}_{3}.$ However, in contrast to the situation in ${\mathrm{UPd}}_{2}{\mathrm{Al}}_{3},$ no spectral gap has been observed in the dynamical susceptibility of ${\mathrm{UNi}}_{2}{\mathrm{Al}}_{3},$ even at the lowest temperature of 0.2 K.