Thermodynamic properties of nm-sized Pd and Ni particles

With decreasing size the density of electronic states of a metal particle becomes different from that of the bulk. This significantly changes the behaviour of the thermodynamic properties of such a particle. We present specific heat and spin susceptibiblity measurements on a series of chemically synthesized Pd particles with diameters of 2.4-15 nm and magnetic measurements on a Ni colloid with an average diameter of about 2.8 nm. Pronounced size dependence of the electronic magnetic properties was found which is accompanied by only weak size dependence of the electronic specific heat. This result can be understood in terms of a size-dependence of the Stoner enhancement factor, which only enters into the susceptibility and not into the specific heat.