Microstructure and magnetic properties of FeCoN thin films

Effects of nitrogen contents and substrate temperatures to the microstructure and magnetic properties of the FeCoN films have been investigated. According to the TEM and x-ray Scherrer's equation analyses, we found that the grain size of films with substrate temperature below 200 degrees C is roughly about 13 nm, however, it increases very fast for films with substrate temperature above 300 degrees C. N content in the films is saturated to 30 at. %, as N-2 flow ratio N-2/(Ar + N-2) is higher than 5 vol. %. From the magnetization studies, we have found that the saturation magnetization 4 pi M-s of the optimum samples (with the substrate temperature near 200 degrees C) is 23.9 kG. The improvement of the magnetic properties is attributed to the combination of alpha-Fe with N to form the high magnetic moment FeN phases. (C) 1998 American Institute of Physics.