EPITAXIAL FE16N2 FILMS GROWN ON SI(001) BY REACTIVE SPUTTERING

We present a crystallographic template for the growth of the range of Fe-N phases on Si(001) by lattice matching on selected underlayers. Ep itaxial films of pure alpha-Fe, gamma'-Fe4N, and alpha'-Fe8N (N marten site) were grown individually by the optimization of reactive Nz Sputt ering parameters. The orientation relation of the Fe-N phases was FeN( 001)\\Ag(001)\\Si(001) and Fe-N[100]\\Ag[110]\\Si[100]. Annealing the alpha'-Fe8N films resulted in the formation of alpha'-Fe8N/alpha ''-Fe 16N2 mixtures. In addition to the crystallographic and structural anal ysis, quantification of x-ray diffraction peak intensities confirmed t hat the alpha'/alpha '' mixtures contained as much as 46 vol % alpha ' ' (remaining alpha'). Vibrating sample magnetometry and SQUID magnetom etry measurements of the alpha' and alpha'(54%)/alpha ''(46%) mixture, respectively, indicate enhanced magnetic moments for both the alpha' and alpha '' phases with respect to pure Fe. (C) 1996 American Institu te of Physics.