公开(公告)号：JP2001023144A

公开(公告)日：2001-01-26

申请号：JP2000159518

申请日：2000-05-30

Applicant: IBM

Inventor： FULLERTON ERIC EDWARD ,  MARGULIES DAVID THOMAS ,  MARINERO ERNESTO ESTEBAN ,  MANFRED ERNST SHABESU

IPC: G11B5/64 ,  G11B5/65 ,  G11B5/66 ,  G11B5/73 ,  G11B5/738 ,  G11B5/851 ,  H01F10/14 ,  H01F10/16 ,  H01F10/28 ,  H01F10/30 ,  H01F41/16 ,  H01F41/32

Abstract: PROBLEM TO BE SOLVED: To obtain a magnetic recording medium comprising a thin magnetic layer having a high coersive force, a high squareness ratio and a low product (Mrt) of a low residual magnetization and thickness to realize a writing operation keeping the thermally stable and extremely high recording density. SOLUTION: This magnetic recording medium comprises a magnetic recording layer having a ferro-magnetic host layer 15 and a ferro-magnetic overlay 17 which is attached in direct on the host layer 15 and has an effective thickness in the range of 1 to 40 Å. The ferro-magnetic overlay material includes Co, Fe or Ni or combination of these materials and also has a magnetic moment which is larger than that of the ferro-magnetic host layer 15. The ferro-magnetic overlay 17 improves thermal stability through magnetic coupling of ferro-magnetic host particles having small bridging. When the thermal stability of a medium increases, use of a thinner ferro-magnetic host layer 15 can be realized and thereby a higher recording density can be obtained from the product (Mrt) of smaller residual magnetization and thickness.