Unpolarized and polarized neutron reflectometry for magnetic structure of nickel-copper multilayer film

A room temperature neutron reflectometery study of a [Ni/Cu] multilayer, grown on Si substrate, has been presented. Close lattice constants of Ni and Cu allow low interfacial roughness in a Ni/Cu multilayer. However, Ni and Cu are also miscible over the entire range of compositions and may cause alloy formation at the interface. Neutron reflectometry in both unpolarized as well as polarized mode gave the full description of nuclear and magnetic (in-plane averaged) scattering length density as a function of depth. The polarized neutron reflectivity measurement showed that there is a reduction in the magnetic moment of Ni atom compared to its bulk value. Drastic reduction of Ni moment at the interface and presence of moment in the Cu layers indicate strong alloying at the interfaces.