Hgst Netherlands, B.v.

Andrew Thomas McCallum

Dieter Klaus Weller

Olav Hellwig

Jeffrey Scott Lille

Michael Grobis

Ernesto Esteban Marinero

Lidu Huang

Oleksandr Mosendz

Simone Pisana

A method for making a bit-patterned-media magnetic recording disk with discrete magnetic islands includes annealing the data islands after they have been formed by an etching process. A hard mask, such as a layer of silicon nitride or carbon, may be first formed on the recording layer and a patterned resist formed on the hard mask. The resist pattern is then transferred into the hard mask, which is used as the etch mask to etch the recording layer and form the discrete data islands. After the data islands are formed by the etching process, the patterned recording layer is annealed. The annealing may be done in a vacuum, or in an inert gas, like helium or argon, or in a forming gas such as a reducing atmosphere of argon plus hydrogen. The annealing improves the coercivity, the effective saturation magnetization and the thermal stability of the patterned media.

Method for improving a patterned perpendicular magnetic recording disk with annealing

A thermally-assisted recording (TAR) disk has an improved insulating layer beneath the chemically-ordered FePt (or CoPt) alloy recording layer. The insulating layer is a solid substitution crystalline alloy MgXO, where the element X is selected from nickel (Ni) and cobalt (Co). The composition of the MgXO crystalline solid substitutional alloy is of the form (MgX)O where y is between 10 and 90, and more preferably between 20 and 80. An optional layer of crystalline 'pure' MgO may be located between the MgXO layer and the FePt recording layer and in contact with the recording layer, or between an underlayer and the MgXO layer.

Thermally-assisted recording (TAR) disk with low thermal-conductivity underlayer

A method for making a bit-patterned-media (BPM) magnetic recording disk includes depositing a FePt (or CoPt) alloy recording layer, and then depositing a sealing layer on the FePt layer before high-temperature annealing. The high-temperature annealing causes the FePt to become substantially chemically-ordered in the L1phase. After annealing, the sealing layer is removed. The sealing layer prevents nanoclustering and agglomeration of the FePt material at the surface of the FePt layer and the sealing layer, which would result in undesirable high surface roughness of the FePt, making patterning of the FePt layer difficult. The FePt layer can be patterned into the discrete islands for the BPM disk either before deposition of the sealing layer or after deposition and removal of the sealing layer. After patterning and removal of the sealing layer, the disk protective overcoat is deposited over the discrete data islands.

Method for making a patterned perpendicular magnetic recording disk having a FePt or CoPt chemically ordered recording layer

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Andrew Thomas McCallum