Magnetic and structural characterization of sputtered FeN multilayer films

The magnetic and structural properties of ferromagnetic FeN thin films, FeN/FeN (ferromagnetic/paramagnetic), and FeN/SiO2 multilayers deposited in a rotational dc magnetron sputter system were investigated. Monolithic films containing ≅2 at. % N2 had 4πMs values ≅25 kG. The Fe16N2 phase has been identified by electron microdiffraction in these films. Saturation magnetostriction (λs) has been related to N2 content and can be varied from -3×10-6 to 5×10-6 in a range of compositions where 4πMs is ≳22 kG. Lamination reduced easy and hard axis coercivity to <1 Oe and produced single domain configurations in yoke-shaped structures. Lorentz microscopy indicated that the ferromagnetic FeN layers in the FeN/FeN films were exchanged coupled while those in the FeN/SiO2 films were magnetostatically coupled.