Evolution of structure and magnetic properties of nanocrystalline FeXN thin films via Ta and Al addition

Nanocrystalline FeAlN and FeTaN films are prepared by direct growth and crystallization of their as-deposited amorphous films, respectively. Although both films show soft magnetism of nanocrys-talline, the uniaxial anisotropy is to be observed different. Measurements of microstructure reveal that Ta addition leads to higher N-solubility in these films, and results in larger lattice dilation and more compressive stress. The uniaxial anisotropy is the consequence of the anisotropic distribution of inter-stitial N atoms in anα-Fe lattice. Al is easy to react with nitrogen, therefore, the α-Fe is purer in an FeAlN films than in an FeTaN ˉlm and the stress is tensile in FeAlN film. The difference of anisotropy may be attributed to the difference between the microstructures in both films.