Electrical resistivity and magnetic behavior of PdNi and CuNi thin films

Electrical and magnetic properties of sputtered Pd86Ni14, Cu46Ni54, and Cu42Ni58 thin films have been investigated. Pd86Ni14 shows clear ferromagnetic properties even if magnetic clusters of 4.6 mu(B) are observed above the Curie-Weiss temperature, T-CW. Different magnetic properties are observed in CuNi alloys. Below T-CW, the field cooling susceptibility increases quasilinearly, while very large magnetic clusters, up to 10-12 mu(B), are observed above T-CW. The temperature behavior of the resistivity of the thin films of the three alloys shows some common features. In particular, after a minimum the resistivity increases, probably due to the scattering of conduction electrons with Ni clusters. The temperature at which the minimum appears does not seem to depend on the host metal (Pd or Cu) and on the Ni concentration. These magnetic clusters affect the resistance behavior in the temperature range where the alloys are paramagnetic or close to their magnetic transition.