Magnetic and phonon contributions to the specific heat of PdNi alloys between 1.8 and 300K

Abstract

The magnetic and phonon specific heats of PdNi alloys with Ni concentration between 1 and 20 at.% Ni have been determined in the temperature range 1.8 to 300K. The change in phonon specific heat on alloying is shown to be consistent with neutron scattering data and provides evidence for the suppression with the addition of Ni of the Kohn anomaly in the (O zeta zeta ) Tl branch of Pd. Magnetic specific heat anomalies are observed which clearly show a progression with increasing Ni concentration from single-particle to cooperative-ordering behaviour, and are consistent with a homogeneous model of ferromagnetically interacting Ni local moments with a spin of 1/2 and a Kondo temperature of 100 to 150K.