Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2005-09-06
2005-09-06
Bernatz, Kevin M. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of inorganic material
Reexamination Certificate
active
06939626
ABSTRACT:
Multiple embodiments of the invention are described which include at least two laminated ferromagnetic layers with differing magnetic anisotropy. The independent magnetic layer farther away from the recording head is selected to have a lower magnetic anisotropy to allow magnetic switching of the multiple magnetic layers to occur at approximately the same head write current even though the recording head field is reduced with increased distance from the head. The improved switching yields improved magnetic recording performance. Laminated magnetic media according to the invention can have a single peak in the normalized DC erase noise vs. head write current plot indicating that the magnetic transitions in the non-slave magnetic layers are written at the same head write current. As a result the magnetic pulse width (PW50) is reduced, overwrite (OW) is improved and media signal-to-noise ratio (SoNR) is improved. Alternatively one or both of the laminated ferromagnetic layers can be replaced with an antiferromagnetically (AF) coupled layer structure that has an AFC-master and an AFC-slave layer separated by a spacer layer selected to antiferromagnetically couple the AFC-master and AFC-slave layers.
REFERENCES:
patent: 5051288 (1991-09-01), Ahlert et al.
patent: 5462796 (1995-10-01), Teng et al.
patent: 5851643 (1998-12-01), Honda et al.
patent: 6280813 (2001-08-01), Carey et al.
patent: 6304081 (2001-10-01), Richter
patent: 6777112 (2004-08-01), Girt et al.
patent: 2001/0009730 (2001-07-01), Futamoto et al.
patent: 2002/0098390 (2002-07-01), Hoa Van Do et al.
patent: 2002/0132140 (2002-09-01), Igarashi et al.
patent: 2002/0192506 (2002-12-01), Coffey et al.
patent: 2003/0017369 (2003-01-01), Hirayama et al.
patent: 2003/0099866 (2003-05-01), Takahashi et al.
patent: 2003/0232218 (2003-12-01), Sato et al.
S.E. Lambert, et al., “Reduction of Media Noise in Thin Film Metal Media by Lamination”, IEEE Transactions on Magnetics, vol. 26, No. 5, Sep. 1990, pp. 2706-2709.
E. S. Murdock, et al., “Noise Properties of Multilayered Co-Alloy Magnetic Recording Media”, IEEE Transactions on Magnetics, vol. 26, No. 5, Sep. 1990, pp. 2700-2705.
A. Murayama, et al., “Interlayer Exchange Coupling in Co/Cr/Co Double-Layered Recording Films Studied by Spin-Wave Brillouin Scattering”, IEEE Transactions on Magnetics, vol. 27, No. 6, Nov. 1991, pp. 5064-5066.
S. E. Lambert, et al., “Laminated Media Noise for High Density Recording”, IEEE Transactions on Magnetics, vol. 29, No. 1, Jan. 1993, pp. 223-229.
E. Teng et al., “Flash Chromium Interlayer for High Performance Disks with Superior Noise and Coercivity Squareness”, IEEE Transactions on Magnetics, vol. 29, No. 6, Nov. 1993, pp. 3679-3681.
Bernatz Kevin M.
Hitachi Global Storage Technologies - Netherlands B.V.
Knight G. Marlin
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