Influence of the magnetic phase transition on secondary ion emission from disordered Ni-Pd compounds of various compositions

Variations in secondary ion emission (SIE) from polycrystals of ferromagnetic disordered Ni-Pd compounds irradiated by argon ions with energy of 10 keV are studied experimentally. A considerable reduction in Ni⁺ and Pd⁺ ion emission upon transitioning from the ferromagnetic to the paramagnetic state is revealed for the following Ni-Pd compounds with various Curie points T _C: NiPd (T _C = 190°C), Ni₅Pd (T _C = 315°C), and NiPd₅ (T _C = 110°C). The observed reduction in SIE is attributed to variations in the surface binding energy and the density of electron states near the Fermi level.