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AssigneeFuji Electric Co., Ltd.
InventorsMiyabi Nakamura, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa, Tadaaki Oikawa
Estimating the term…
A magnetic recording medium exhibiting low noise and having a sufficiently high coercive force includes a magnetic layer having a granular structure including ferromagnetic crystal grains with a hexagonal closest packed structure and a nonmagnetic grain boundary region of mainly an oxide intervening between the crystal grains. An underlayer has a body-centered cubic lattice structure. A nonmagnetic intermediate layer with the hexagonal closest packed structure includes Ru, Os, and/or Re, which are provided between the magnetic layer and the underlayer. A degree of mismatching Δ=|d1−d2|/d1 is at most 10%, for instance, in a range from 2.5% to 7.0%, where d1 is a spacing of lattice planes of the crystal grains in the magnetic layer and d2 is a spacing of the lattice planes of the crystal grains in the intermediate layer. A proportion of the crystal grains with a grain size of equal or greater than 8 nm are at most 10% of the crystal grains included in the intermediate layer and a standard deviation of the grain size is at most 1.4 nm. The layers are deposited without preheating the substrate.
A magnetic recording medium, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
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Characterised by its composition: containing oxygen, e.g. molecular oxygen or magnetic oxide
Two or more non-magnetic underlayers, e.g. seed layers or barrier layers: physical structure of underlayer, e.g. texture
Magnetic recording media substrates: organic polymer substrates
Information storage based on relative movement between record carrier and transducer
Term end not estimated
This application claims the benefit of Japanese Application No. 2001-382164 filed Dec. 14, 2001 in the Japanese Patent Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates in general to a magnetic recording medium and, in particular, to a high performance and highly reliable magnetic recording medium that exhibits low noise and sufficiently high coercive force and is mounted on a variety of magnetic storage devices, such as an external storage device of a computer.
These and other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic cross-sectional view of an example of an embodiment of a magnetic recording medium, according to an aspect of the present invention.
FIG. 2 is a planar TEM image of a magnetic layer of the magnetic recording medium.
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.
FIG. 1 is a drawing illustrating an example of a construction of a magnetic recording medium, according to an aspect of the present invention. Sequentially laminated on a substrate 1 are an underlayer 2, a nonmagnetic intermediate layer 3, a granular magnetic layer 4, a carbon protective layer 5, and a lubricant film 6.
The substrate 1 may be a 3.5 inch diameter disk of polyolefin resin with a smooth surface. After cleaning, the substrate is introduced into a sputtering apparatus and an underlayer 2 with a body centered cubic structure is deposited thereon using a DC sputtering method.