Substrate Bias Effect on Magnetic Properties of Sputter Deposited Co/Pt Multilayers

Co/Pt multilayer films were prepared by rf sputtering with a negative substrate bias voltage (VB) applied. The morphology of the multilayer films changed from a columnar structure to a fine-textured structure on applying the bias VB. A bias voltage of about ¿30 V improves the flatness and sharpness of the interface and causes a decrease in the perpendicular coercivity, because of the reduction of pinning effects at the layer surfaces and/or column boundaries. In low-coercivity films prepared with a bias voltage applied, Bitter observations clearly revealed stripe domains.