Uniaxial magnetic FeC thin films sputtered onto polymer substrates

Thin films of FeC were deposited onto a polymer substrate by reactive DC magnetron sputtering, using an argon and hydrocarbon gas mixture. The polymer web is wound by a roll coater, and an individual thin film with a constant thickness is piled up by increasing a number of passes UP to a desired thickness. Uniaxial films with Hk=4000 A/m and low dispersion were obtained. The coercive force was a function of thickness; it was Hc=8 A/m for films 0.8 /spl mu/m thick. The easy axis of the uniaxial anisotropy was along the direction transverse to the rolling direction of the polymer web. The origin of the uniaxial anisotropy is the anisotropic thermal shrinkage of the polymer web is discussed by a model.