Magnetic Thin Films Prepared by Sputtering

Experimental study of magnetic thin films prepared by sputtering in a glow discharge environment showed that crystal structure and chemical purity, as well as particle size and surface morphology, can be controlled. Different physical properties, including B-H characteristics, can be reproducibily obtained by the location of the collecting substrate with respect to the characteristic zones of the glow discharge; e.g., Crookes dark space, negative glow, positive column, etc. This is the result of variations in deposition rate and energy distribution of the material arriving at the substrate, as well as variations in intensity of electron bombardment and the consequent temperature of the substrate. Typical results on nickel and iron films are reported. In contrast to several reports in the literature, ferromagnetic fcc nickel films were deposited directly by sputtering. Completely unoriented, polycrystalline bcc Fe films were prepared in which $\text{Br/Bs∼1}$ , $H_c\text{∼250\hspace{0.17em}}\mathrm{oe}$ , and $\text{Br∼20\hspace{0.17em}000}\mathrm{oe}$ ; i.e., the magnetic characteristics were quite different from those obtained by high vacuum evaporation.