NIO ALPHA-FE2O3 MULTILAYERS PREPARED BY PLD - A MODEL SYSTEM FOR MAGNETIC STUDY OF INTERDIFFUSION/

We prepared multilayer Alms based on NiO and alpha Fe2O3 by pulsed las er ablation. In these too NiO/alpha Fe2O3 and alpha Fe2O3/NiO multilay ers, interdiffusion leads to the formation of the nickel ferrite NaFe2 O4 at the interfaces. Its ferrimagnetism provides a local probe on the admixture of the antiferromagnetic oxides NiO and alpha Fe2O3 which i s macroscopically measurable. We performed magnetization, torque and m agneto-optical measurements on the multilayer samples. Surprisingly, a n oscillation of the total magnetic moment rm as a function of the num ber of interfaces was observed. The oscillation of m reverses when the succession of NaO/alpha Pe(2)O(3) layers is inverted to alpha Fe2O3/N iO multilayers. This indicates a magnetical and structural nan equival ence of the NiO/alpha Fe2O3 and the alpha Fe2O3/NiO interfaces. This o scillation is observed in the magnetization, the Faraday effect and th e coercive fields. Furthermore, Secondary Ion Mass Spectroscopy measur ements (SIMS) on some NiO/alpha Fe2O3 samples showed a well formed mul tilayer structure with pronounced interlayers. The presence of NiFe2O4 can be seen from transmission spectroscopy measurements which we perf ormed on the alpha Fe2O3/NiO multilayers series.