Correlations among sputter pressure, thickness, and coercivity in Al/Co/Cu magnetic thin films sputtering

We demonstrate the effect of sputter gas pressure and film thickness, d, on the coercivity of Co in Al/Co/Cu sputterdeposited on Si(001). Increased sputter gas pressure produces increased rms roughness and increased O content in our films. The deposited Co thickness at which the onset of ferromagnetism is first observed, d_c, increases with sputter gas pressure. Above this thickness,d > d_c, the coercivity increases with increasing Co thickness. For film thickness d ≫ d_c, the coercivity is thickness independent. We show that coercivity is directly controllable at technologically relevant thicknesses by regulating sputter-deposition parameters.