Study of Al–C multilayers using anomalous reflectivity and high quantum wells using resolution diffraction studies of multilayers

Abstract

Polarized neutron reflectivity with polarization analysis enables one to determine in-plane vectorial magnetic depth profiles.We investigated the modifications of the magnetostrictive properties of nickel and nickel-iron thin films due to relaxation strains at the substrate/film and film/vacuum interfaces. The inplane magnetization rotation induced by a mechanical applied strain is shown to be non homogeneous throughout the layer. For a 100 nm iron-nickel thin film, the magnetization varies from 50° at the vacuum/film interface to 60° at the substrate(glass)/film interface. In a 40 nm nickel film, we observed that the magnetization rotation went up to 80° in the first 5 nm of the glass/nickel interface and decreased quickly to 34 ° in the rest of the layer.Other measurements were made on trilayers systems Ni/ NiFe/Ni and Ni/ Ag/NiFe in order to observe the magnetic coupling between the layers. The magnetic alloys were chosen in order to have magneto-elastic constants of opposite signs so that the rotation directions induced by a strain are perpendicular for the two alloys. The Ni/NiFe/Ni system is shown to have a rather homogeneous magnetization whereas the Ni/ Ag/NiFe trilayer exhibits magnetic rotation gradients in both layers.