F. Thimon et al., STUDY OF FE - AL2O3 ION-BEAM SPUTTERED THIN-FILMS WITH VARIOUS IRON CONTENTS, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 80-1, 1993, pp. 1241-1244
Iron and Al2O3 were simultaneously ion beam sputtered on polycrystalli
ne alumina substrate at room temperature. The atomic iron concentratio
n was varied in the range 5-60 at.%. Thicknesses of the films (approxi
mately 450 nm) and iron concentrations were controlled using Rutherfor
d backscattering spectrometry (RBS). Iron charge states and phases wer
e deduced from conversion electron Mossbauer spectroscopy (CEMS) and g
razing-angle X-ray diffraction (GXRD) measurements. At low iron concen
trations, CEMS shows that iron is mainly dispersed in Al2O3 together w
ith the presence of small iron precipitates. GXRD confirms the formati
on of the FeAlO3 phase and iron aggregates. Around 40 at.% of iron big
ger precipitates appear, whereas for 50 at.% magnetic aggregates with
different sizes are formed. For the highest concentration only magneti
cally ordered metallic particles are detected.