Inelastic polarized and unpolarized neutron scattering measurements onUBe13

Abstract

We present the results of polarized and unpolarized inelastic neutron scattering measurements of the heavy-fermion superconductor ${\mathrm{UBe}}_{13}$ at 10 K. At this temperature, the energy spectrum of the magnetic scattering is characterized by a broad quasielastic Lorentzian line shape modified by the Bose occupation factor, with a width of 13±2 meV (half-width at half maximum). No evidence of a narrow (few meV) f-level resonance predicted by the electronic specific-heat coefficient is observed. The energy-integrated magnetic scattering yields a susceptibility which is consistent with bulk measurements, indicating that any additional response must have a small spectral weight.