Temperature dependence of low-energy phonons in magnetic nonsuperconducting TbNi2B2C

Abstract

We report temperature dependence of low-energy phonons in magnetic nonsuperconducting TbNi${}_{2}$B${}_{2}$C single crystals measured by inelastic neutron scattering. We observed low-temperature softening and broadening of two phonon branches, qualitatively similar to that previously reported for superconducting $R$Ni${}_{2}$B${}_{2}$C $(R=\text{rare}$ earth, $Y$) compounds. This result suggests that superconductivity in TbNi${}_{2}$B${}_{2}$C compounds is absent not because of weak electron-phonon coupling but as a result of pair breaking due to magnetism.