Fe-N films: Morphology, static and dynamic magnetic properties

The study is conducted of thin Fe-N films produced by magnetron sputtering on mylar substrate. The correlations between morphology, structure, and magnetic static and dynamic properties of the films are found. The films under study have a columnar morphology. Both the average granule size and the length-to-width ratio of the granules increase with the film thickness that causes an increase of the effective anisotropy field. A small variation of nitrogen fraction in Ar + N-2 gas mixture in the sputtering chamber allows the location of magnetic loss peak to be controlled within the frequency range of 1-5GHz. Therefore, the frequency dependence of permeability is determined not only by the crystalline structure and composition of the film but also by its morphology, thickness, and effective magnetic anisotropy. In particular, with the fixed concentration of nitrogen in the film, the frequency dependence of microwave permeability is determined greatly by the distribution of nitrogen atoms over different vacancies in the film structure. (c) 2007 Elsevier B.V.. All rights reserved.