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

TL;DR

This study investigates low energy spin fluctuations in a heavy fermion compound near a magnetic quantum critical point, revealing saturation behavior of relaxation rate and susceptibility at low temperatures.

Contribution

It provides new inelastic neutron scattering data showing saturation of spin fluctuation parameters in Ce$_{0.925}$La$_{0.075}$Ru$_{2}$Si$_{2}$ at low temperatures.

Findings

Saturation of relaxation rate at low temperatures.

Saturation of static susceptibility at low temperatures.

Spin fluctuations persist without divergence near the critical point.

Abstract

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.