Optimization of the Substrate Temperature for a Paramagnetic Seed Layer in a Co-Cr Perpendicular Recording Medium

Abstract

Ferromagnetic Co₇₇Cr₂₀Ta₃ layers were deposited on paramagnetic Co₆₅Cr₃₅ and Pt seed layers. The crystallographic and magnetic characteristics of the Co-Cr-Ta layer were improved by independently adjusting the substrate temperature T_s of the Co₆₅Cr₃₅ seed layer in the range 150°C - 200°C. The Pt seed layer results in better c-axis orientation even at a low T_s of around 250°C, and a 50-nm-thick Co-Cr-Ta layer deposited on it exhibited a high perpendicular coercivity H_c⊥ of 2.5 kOe at a T_s of 250°C. Optimization of T_s for the paramagnetic Co-Cr layer and use of the Pt seed layer were effective for depositing ultra-thin Co-Cr-Ta recording layers.