Abstract: A patterned perpendicular magnetic recording disk has a Co-alloy recording layer patterned into discrete data islands arranged in concentric tracks and exhibits a narrow switching field distribution (SFD). The disk includes a substrate, a NiTa alloy planarizing layer on the substrate, a nonmagnetic Ru-containing underlayer on the planarizing layer, an oxide-free Co alloy magnetic recording layer, and an ultrathin oxide film between the Ru-containing layer and the Co-alloy magnetic recording layer. The oxide film may be an oxide selected from a Ta-oxide, a Co-oxide and a Ti-oxide, and is ultrathin so that it may be considered a discontinuous film. The planarizing layer and ultrathin oxide film improve the growth homogeneity of the Co-alloy recording layer, so that the patterned disk with data islands shows significantly reduced SFD.

Abstract: A hard disk drive has a magnetic media disk comprising a substrate having an axis, and an exchange coupled, bit patterned media on the substrate arranged in a plurality of tracks. Each of the tracks has a pattern of islands extending in an axial direction from the disk. Each island comprises a first layer having a first anisotropy and a first layer radial width, and a second layer on the first layer and having a second anisotropy that is lower than the first anisotropy. The second layer radial width is less than the first layer radial width.

Abstract: According to one embodiment, a multilayered nonmagnetic underlayer is provided under a perpendicular magnetic recording layer, which has a structure in which a nonmagnetic template layer consisting of ruthenium and silicon is formed between a first nonmagnetic underlayer consisting of one of ruthenium and a first ruthenium alloy sputtered in an inert gas ambient, and a second nonmagnetic underlayer consisting of one of ruthenium and a second ruthenium alloy sputtered in an inert gas ambient at a pressure higher than that when sputtering the first nonmagnetic underlayer.