Oxidation of NiFe(20 wt.%) thin films

The oxidation of sputtered NiFe(20 wt.%, Permalloy) thin films with a thickness of 180 nm was studied during annealing up to 400 °C for 2 h in air. The composition and the thickness of the oxide layer and the compositional change in the NiFe alloy layer as well as the microstructure of the film were investigated by Auger electron spectroscopy, X-ray diffraction, and transmission electron microscopy. Distinct oxidation starts at about 300 °C. The formed oxide layer consists of Fe2O3. The Fe concentration in the NiFe layer decreases with the oxidation which leads to changes of the properties of this layer.