Low energy spin fluctuations in the heavy fermion compound Ce$_{0.925}$La$_{0.075}$Ru$_{2}$Si$_{2}$

We report inelastic neutron scattering measurements performed on a single crystal of the heavy fermion compound Ce$_{0.925}$La$_{0.075}$Ru$_{2}$Si$_{2}$, which is at the borderline between an antiferromagnetically ordered and a paramagnetic ground state. Intensity maps as a function of wavevector and energy ($0.1<E<1.2$ meV) were obtained at temperatures $T=0.1$ and 2 K, using the time-of-flight spectrometer IRIS. An unexpected saturation of the relaxation rate and static susceptibility of the spin fluctuations is found at low temperatures.