Epitaxial growth and magnetic properties of Fe16N2 films with high saturation magnetic flux density (invited)

Fe-N films with thicknesses of 70–1000 Å were deposited by MBE onto Fe films which were epitaxially grown onto GaAs(100) substrates. Without the Fe layer, epitaxially grown Fe-N films could not be obtained due to a reaction between Fe-N and GaAs. TEM observations and x-ray diffraction patterns showed that the epitaxially grown Fe-N films consist of Fe16N2 and Fe, and that crystal orientation is Fe16N2 (001)//Fe(110). It was found that the saturation magnetic flux density (Bs) increases as the thickness of the Fe-N films decreases. This is because the volume ratio of Fe16N2 in the Fe-N films increases with decreasing Fe-N film thickness. The maximum value for Bs is 2.66 T, and the volume ratio is 85%. These results indicate that Fe16N2 has a high saturation magnetic flux density of 2.8–3.0 T.