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perpendicular magnetic
recording (PMR) method
Because of the demand for higher density hard disk, perpendicular magnetic recording (PMR) method become more popular recently than its predecessor - longitudinal recording.
The main advantage of PMR is that it achieves higher storage density by aligning the poles of the magnetic elements, which represents bits perpendicularly to the surface of the disc platter.
The thin-film layers composing PMR are formed by sputtering method.
Toshima offers PMR-materials with high-quality read-, write-, and high yield rate properties. These features can be attained by elimination of "particles", i.e. bulky grains, during the sputtering process.
The structure of the target plays an important role in reducing the particles.
Herewith, the dominant factor is that the grains composing the sputtering target should be refined and homogeneous.
Please see the SEM pictures of our CoCrPt-X target below.
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Old method
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New method
The left-side photo shows the large grains were generated by our old manufacturing process.
By contrast, the right-side picture is the evidence of the refined-grain by the new method.
