| US 7,446,969 B2 | ||
| Thermally assisted recording system | ||
| Fumiko Akagi, Tokyo (Japan); Masukazu Igarashi, Saitama (Japan); and Hideki Saga, Tokyo (Japan) | ||
| Assigned to Hitachi Global Storage Technologies Netherlands B.V., Amsterdam (Netherlands) | ||
| Filed on May 19, 2005, as Appl. No. 11/134,088. | ||
| Claims priority of application No. 2004-149477 (JP), filed on May 19, 2004. | ||
| Prior Publication US 2005/0259343 A1, Nov. 24, 2005 | ||
| Int. Cl. G11B 5/02 (2006.01) | ||
| U.S. Cl. 360—59 [360/135; 428/817; 428/829; 428/836.1] | 19 Claims |
| 1. A thermally assisted recording system comprising a magnetic recording medium, a magnetic pole applying a magnetic field
H to said magnetic recording medium, and a heating mechanism to heat a magnetic field applied region of said magnetic recording
medium while recording, wherein
said magnetic recording medium includes a substrate and a recording layer formed on a substrate,
said recording layer includes a ferromagnetic layer,
a magnetic exchange coupling energy between magnetic grains comprising said ferromagnetic layer is controlled to be large
at room temperature to let the magnetization of said magnetic grains be thermally stable, and is reduced drastically to make
the magnetization transition slope steep while recording, and
in an MH-loop providing a relationship between the magnetization M of said ferromagnetic layer and the magnetic field H, a
parameter A which is obtained by normalizing said MH-loop slope parameter around the coercivity of the magnetic field applied
region of said magnetic recording medium becomes nearly 1 by heating using the said heating mechanism while recording, wherein
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