Study of non-Fermi-liquid behaviour near the ferromagnetic quantum critical point in CePd 0.15Rh 0.85

Abstract

Recent bulk measurements on CePd 1− x Rh x alloys indicate a ferromagnetic quantum critical point (FQCP) near the critical composition x c=0.85. We present here the first results of the spin dynamics near the FQCP in CePd 0.15Rh 0.85 investigated using inelastic neutron scattering measurements over a wide temperature range between 5 and 260 K. Our study reveals a strong quasielastic scattering between 5 and 260 K, which is nearly temperature independent on the neutron energy loss side, but follows the population factor on the neutron energy gain side. Furthermore, we found a novel E/T scaling behaviour, with the scaling exponent α=0.6, of the dynamical susceptibility, χ( E,T). At low temperatures (below 60 K) the quasielastic linewidth ( Γ) exhibits a linear temperature dependence, which is in agreement with the theoretical prediction for non-Fermi-liquid behaviour near a QCP. We compare the observed scaling behaviour in CePd 0.15Rh 0.85 near the FQCP with that of systems having an antiferromagnetic QCP or a spin-glass quantum-type critical point.