Perpendicular Magnetic Disc
AssigneeWD Media (Singapore) Pte. Ltd.
InventorsTokichiro Sato, Takenori Kajiwara
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Abstract
[Problem] To make a film thinner while keeping a function as an auxiliary recording layer, and improve an SNR and an overwrite characteristic. [Solution] A typical structure of a perpendicular magnetic disk according to the present invention includes, on a base, a granular magnetic layer 160 and an auxiliary recording layer 180 disposed on the granular magnetic layer 160. The granular magnetic layer 160 has a granular structure in which a grain boundary part is formed with segregation of a non-magnetic substance having an oxide as a main component around magnetic particles having a CoCrPt alloy a main component growing in a columnar shape. The auxiliary recording layer 180 has a CoCrPtRu alloy as a main component, and has a film thickness of 1.5 nm to 4.0 nm.
Claims3
A perpendicular magnetic disk including, on a base, an amorphous alloy layer, a preliminary ground layer provided on the amorphous alloy layer, a ground layer formed of Ru or a Ru-type alloy having an hcp crystal structure provided on the preliminary ground layer, and a granular magnetic layer provided on the ground layer, wherein
- the amorphous alloy layer contains Ta, and
- the preliminary ground layer includes a first preliminary ground layer formed of Ti or a Ti alloy of microcrystals and a second preliminary ground layer formed of a Ni-type alloy of an fcc crystal structure.
Dependencies are inferred from the claim text.