Abstract:
PROBLEM TO BE SOLVED: To provide a magnetic disk which is improved in the medium saturation coercive force of a film structure by use of a CrNi preseed layer. SOLUTION: The thin-film magnetic disk is formed by sputtering the crystalline CrNi preseed layer on a substrate consisting of glass, etc., and in succession bonding an RuAl seed layer thereto. The CrNi preseed layer reduces particle sizes and their distribution, thereby improving the intra-surface crystal orientation, saturation coercive force (Hc) and signal-to-noise ratio(SNR). In an adequate embodiment, a lower layer of a Cr alloy is bonded in succession to the RuAl seed layer. In a more adequate embodiment, an onset layer and a magnetic layer or >=2 magnetic layers to be antiferromagnetically bonded across >=1 spacer layer are bonded in succession to the under layer of the Cr alloy. Since the crystalline CrNi preseed layer makes the use of the thinner RuAl seed layer possible, the particle size over the entire particularly is reduced and eventually the manufacturing cost of the magnetic disk occurring in relatively costly ruthenium is reduced. The CrNi preseed layer makes the use of the lower layer of the thinner Cr alloy possible and again contributes to the reduction of the particle size over the entire part.
Abstract:
PROBLEM TO BE SOLVED: To obtain a multilayered magnetic layer exhibiting single switching operation with a smooth hysteresis loop by depositing a multilayered magnetic layer of two or more layers with crystalline orientation PO[1010] with min. changes in the coercive force Hc of each magnetic layer. SOLUTION: A seed layer 12 having B2 structural material, a nonmagnetic base layer 13 such as chromium and chromium alloy, a magnetic layer 14, a spacer layer 15, a magnetic layer 16 and a coating film 17 are sequentially deposited on a substrate 11. The seed layer 12 and the base layer 13 are required to enhance PO[1010] in the magnetic layers 14, 16. The magnetic layers 14, 16 consist of a cobalt alloy containing platinum and chromium and contain additional elements such as tantalum and boron, and for example, CoPtCrTa or CoPtCrB. Thereby, the two-layer multilayered magnetic film comprising the magnetic layers 14, 16 does not exhibit a two-mode switching effect, so that irregularity in the hysteresis loop can be prevented.
Abstract:
This invention relates to a magnetic recording medium including a substrate carrying a coating of magnetic particles and non-magnetic load-bearing spherical particles dispersed in a binder. The spherical particles protrude above the surface of the magnetic coating. The particles do not protrude above the surface of the magnetic coating by more than 1/5th of the thickness of said coating.
Abstract:
A thin film disk with laminated magnetic layers, for use in a disk drive, is described which exhibits a single switching behavior resulting in a smooth hysteresis loop. This is achieved by depositing a seed layer prior to depositing the Cr or Cr alloy underlayer. The seed layer material is selected to promote a Ä112Ü PO in the underlayer and subsequently a Ä1010Ü PO in the two or more laminated magnetic layers. The Ä1010Ü PO aids in maintaining minimal Hc variations between the magnetic layers. The seed layer can be a B2 type structure material such as NiA1 or FeA1 or any other material which results in the Ä112Ü PO in the underlayer. The underlayer is preferably Cr or a Cr alloy; the magnetic layers are preferably CoPtCr, CoPtCrTa or CoPtCrB. The spacer layer between the magnetic layers may be made from the same material as the underlayer, but may also be different, e.g. an hexagonal crystalline material such as Ru. The disks of the invention can be manufactured in standard high volume sputtering systems by virtue of the fact the magnetic layers have a reduced dependency on substrate temperature.
Abstract:
A magnetic recording disk has both an extremely smooth top surface and high coercivity, and is incorporated in a contact recording disk file which requires an extremely smooth head-disk interface and a disk with high coercivity. A superfinished untextured NiP coating on a disk substrate is oxidized to form a NiO film. The NiO film permits the subsequently sputter deposited magnetic layer to have much higher coercivity, which enables the disk to be used in contact recording applications. The NiO film and the later deposited layers making up the disk, including the top protective overcoat, conform to the smooth surface of the polished NiP, thus preserving the extremely smooth surface of the top layer of the disk, which is required for the head-disk interface in contact recording disk files. In the preferred process for forming the NiO film on the substrate, the substrate is annealed in air at a temperature below that which would cause the NiP film to crystallize.