Neutron scattering studies of the magnetic superconductor (Ce _1-xTb_x)Ru₂

Neutron scattering measurements have been carried out on polycrystalline specimens of (Ce_1-xTb_x)Ru₂, for x = 0.07, 0.18, 0.44, in order to study the inelastic magnetic scattering as well as the development of magnetic correlations at low temperatures. At small wavevectors the intensity in each sample increases with decreasing temperature indicating the development of ferromagnetic correlations at low temperatures, but the intensity saturates at low temperature with no peak in its temperature dependence. There is also no evidence of any magnetic Bragg peaks, which indicates that there is no long range ferromagnetic order. For x = 0.44, inelastic scattering measurements show a distribution of magnetic scattering from low energies up to 4.5 meV, with a relatively well defined maximum at 3.3 meV. At T = 20 K additional scattering appears at 6.6 meV, while the scattering which peaked at 3.3 meV appears to shift to lower energies.