We prepared NiOαFe2O3 multilayer films by pulsed laser ablation. Interdiffusion leads to the formation of the nickel ferrite NiFe2O4 at the interfaces. Its ferrimagnetism provides a local probe on the admixture of the antiferromagnetic oxides NiO and αFe2O3 which is macroscopically measurable. We performed magnetization, torque and magnetooptical measurements on the multilayer samples. Several phenomena were observed. As a function of the substrate temperature a kinetically (due to the incoming particle energies) and a thermally activated regime of NiFe2O4 formation were observed. In the thermally activated regime, the duration of the deposition per layer and therefore the temperature dependent diffusion at the interfaces plays a crucial role to the formation of the ferrite as can be seen from the magnetic moment m which tends to saturate for long in-situ annealing times. Surprisingly, an oscillation of m as a function of the number of interfaces was observed for the NiOαFe2O3 multilayer films. This indicates a magnetically and perhaps structurally non equivalence of the NiOαFe2O3 and the αFe2O3NiO interfaces. This oscillation is observed in the magnetization, the Faraday and the coercive fields.