| US 7,468,852 B2 | ||
| Method of demagnetizing magnetic recording medium and apparatus for carrying out same | ||
| Syuji Nishida, Kanagawa (Japan); Ikuya Tagawa, Kanagawa (Japan); Yasutaka Nishida, Tokyo (Japan); and Satoshi Tabata, Kanagawa (Japan) | ||
| Assigned to Hitachi Global Storage Technologies Netherlands B.V., Amsterdam (Netherlands) | ||
| Filed on May 03, 2006, as Appl. No. 11/417,812. | ||
| Claims priority of application No. 2005-135261 (JP), filed on May 06, 2005. | ||
| Prior Publication US 2006/0250716 A1, Nov. 09, 2006 | ||
| Int. Cl. G11B 5/09 (2006.01) | ||
| U.S. Cl. 360—66 [360/15] | 19 Claims |
| 1. A method of fabricating a perpendicular magnetic recording medium comprising:
a film forming step of forming a soft magnetic under layer, and a perpendicular magnetic recording layer on top of a substrate;
and
a demagnetization step of demagnetizing the perpendicular magnetic recording layer, wherein in the demagnetization step, alternating-current
demagnetization is implemented by applying magnetic fields with alternate polarity in a direction slanting to an easy direction
of magnetization of the perpendicular magnetic recording layer;
wherein the demagnetization step utilizes first magnets having a N-pole and S-pole, as respective magnetic poles thereof,
facing a medium plane, and a second magnets having a S-pole and N-pole, as respective magnetic poles thereof, facing the medium
plane;
wherein the S-pole and the N-pole of the second magnets, respectively, are disposed so as to have an offset in a direction
either orthogonal or parallel to the medium plane, against the N-pole and the S-pole of the first magnets, respectively.
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