Viable scaling mechanism ensuing anomalous Hall effect in Si/Ni multilayers from 2 K-300 K

Abstract

A systematic study of the scaling mechanisms driving the anomalous Hall effect (AHE) in Si/Ni multilayers was conducted from 2 K to 300 K on [Si(40˚A)/Ni(tNi˚A)]20 multilayers. Structural analysis revealed polycrystalline Ni layers and amorphous Si layers. As tNi decreased, Ni nanocrystallite size reduced, while the surface-to-volume ratio and Si/Ni interface roughness increased. Multilayers with tNi ≥ 40˚A exhibited ferromagnetic behavior, while those with tNi < 40˚A were superparamagnetic. Decreasing tNi also increased longitudinal resistivity due to enhanced interface roughness, higher surface-to-volume ratio, and increased tunneling between Ni nanocrystallites. AHE studies showed that Hall resistance peaked with decreasing tNi but declined for tNi < 40˚A, due to superparamagnetism. Skew scattering dominated Hall resistance enhancement at all temperatures, but as the temperature increased from 2 K to 300 K, a transition from skew scattering to the side-jump mechanism was observed.