Abstract: A thin film alloy disk for vertical magnetic recording has a cobalt-chromium-tantalum (CoCrTa) magnetic layer with perpendicular magnetic anisotropy deposited on an underlayer of beta-tantalum (.beta.-Ta). The .beta.-Ta layer is deposited on a suitable substrate, such as silicon, which is compatible with the formation of the beta phase of tantalum. The highly preferred orientation of the .beta.-Ta film on the substrate and the incorporation of Ta in the magnetic film results in the magnetic film having improved perpendicular magnetic anisotropy, high perpendicular coercivity and low horizontal coercivity. A nickel-iron (NiFe) layer may be deposited between the substrate and the .beta.-Ta underlayer to provide a magnetic flux return path.