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Permeability control by RuCr laminated Soft Underlayer for Perpendicular media

IP.com Disclosure Number: IPCOM000131032D
Publication Date: 2005-Nov-04
Document File: 3 page(s) / 40K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a magnetic medium for Hard disk drive (HDD). Permeability of the anti-ferro-coupled soft underlayer (SUL) for perpendicular recording media is one of the key parameters for matching the media with writing head. To control the permeability of SUL, we used RuCr binaly alloy for the internal layer. By changing Cr amount in the alloy, we can easily control the exchange coupling strength, and permeability of SUL.

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Permeability control by RuCr laminated Soft Underlayer for Perpendicular media

  Perpendicular recording is very promising candidate for next generation magnetic recording. Soft underlayer (SUL) is one of the key component of perpendicular media. Since SUL is work as a part of the head during writing, it need to have enough permeability. On the other hand, to minimize stray field erasure and adjacent track writing, the permeability need to minimize. That is why there are optimum permeability for SUL, and the value will be different for each head design, magnetic spacing and drive design. But it was very hard to control the permeability without changing the other SUL parameters such as coercivity Hc , anisotropy field, Hk, saturation field, Bs and thickness. With this invention, we can easily control the permeability without changing those other parameters to optimize the permeability.

Protective layer

Protective layer

CoPtCr-SiOx Recording layer

CoPtCr-SiOx Recording layer

Template layers

Template layers

CoTaZr

CoTaZr

RuCr

RuCr

SUL

SUL

CoTaZr

CoTaZr

Adhesion layers

Adhesion layers

Substrate

Substrate

Figure. 1 Sample film structure for this invention

Figure 1 shows CoTaZr was laminated thin RuCr. By changing the Cr composition of RuCr alloy from 1- 50 at.%, The permeability of the SUL can be changed from 100 - 1000. Most likely, Cr composition range from 20 to 35% is most effective to control the permeability.

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1200

1000

800

Permeability

600

Ru RuCr7 R...