Reduction of Ru Underlayer Thickness for CoCrPt–SiO $_2$ Perpendicular Recording Media

The mechanism of Ta seedlayer to promote (0002) texture in Ru underlayer was found to be mainly due to epitaxial growth of Ru (0002) on Ta (110) with a smooth surface. Relatively high sputtering power and low sputtering pressure as well as an optimized layer thickness are keys to deposit a Ta seedlayer, which can result in a good (0002) texture in Ru layer with a relatively thinner thickness. A Ru intermediate layer deposited at a higher pressure was found to further reduce the overall Ru underlayer thickness without degrading magnetic properties of CoCrPt-SiO 2 perpendicular magnetic recording (PMR) layer. All these results were confirmed by the investigation of surface morphology, microstructure, crystal orientation, and magnetic properties, suggesting that through optimizing the deposition process of Ru/Ta layers, the magnetic "spacing loss" of PMR can be greatly suppressed