公开(公告)号：JP2001148110A

公开(公告)日：2001-05-29

申请号：JP2000307398

申请日：2000-10-06

Applicant: IBM

Inventor： CAREY MATTHEW JOSEPH ,  FULLERTON ERIC EDWARD ,  GURNEY BRUCE ALVIN ,  ROSEN HAL JERVIS ,  SCHABES MANFRED ERNST

IPC: G11B5/708 ,  C23C28/00 ,  C23C28/02 ,  G11B5/64 ,  G11B5/65 ,  G11B5/66 ,  G11B5/673 ,  G11B5/738 ,  H01F10/26

Abstract: PROBLEM TO BE SOLVED: To provide a magnetic recording medium for keeping good thermal stability and SNR and supporting ultra high-density recording. SOLUTION: This magnetic recording medium for a data storage device is constituted of at least two magnetic recording layers of ferromagnetic films, which are adhered to each other in an antiferromagnetic manner, while interposing a nonferromagnetic spacer film. Magnetic moment of one ferromagnetic film works in the direction antiparallel to that of the magnetic moment of the other ferromagnetic film. The balanced magnetic moment is shown as the difference between Mrt values of two ferromagnetic films, when the magnetic moment is shown by net product (Mrt) of residual magnetism (Mr) and thickness (t) in the magnetic recording layer. The decrease in Mrt is achieved, while the thermal stability of the recording medium is not deteriorated, because the volume of particles in ferromagnetic films adhered to each other in an antiferromagnetic manner is increased constructively. Very sharp magnetic transitions can be achieved by the reduced antimagnetic field and higher density of the bit lines can be obtained in this medium as a result.

公开(公告)号：GB2355018B

公开(公告)日：2004-02-11

申请号：GB0015023

申请日：2000-06-21

Applicant: IBM

Inventor： CAREY MATTHEW JOSEPH ,  FULLERTON ERIC EDWARD ,  GURNEY BRUCE ALVIN ,  ROSEN HAL JERVIS ,  SCHABES MANFRED ERNST

IPC: G11B5/708 ,  C23C28/00 ,  C23C28/02 ,  G11B5/64 ,  G11B5/65 ,  G11B5/66 ,  G11B5/673 ,  G11B5/738 ,  H01F10/26 ,  C23C14/14 ,  C23C14/16 ,  G11B5/62 ,  G11B5/84

Abstract: A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films antiferromagnetically coupled together across a nonferromagnetic spacer film. The magnetic moments of the two antiferromagnetically-coupled films are oriented antiparallel, and thus the net remanent magnetization-thickness product (Mrt) of the recording layer is the difference in the Mrt values of the two ferromagnetic films. This reduction in Mrt is accomplished without a reduction in the thermal stability of the recording medium because the volumes of the grains in the antiferromagnetically-coupled films add constructively. In a magnetic recording rigid disk application, the magnetic layer comprises two ferromagnetic films, each a granular film of a sputter deposited CoPtCrB alloy, separated by a Ru spacer film having a thickness to maximize the antiferromagnetic exchange coupling between the two CoPtCrB films. One of the ferromagnetic films is made thicker than the other, but the thicknesses are chosen so that the net moment in zero applied magnetic field is low, but nonzero.

公开(公告)号：GB2355018A

公开(公告)日：2001-04-11

申请号：GB0015023

申请日：2000-06-21

Applicant: IBM

Inventor： CAREY MATTHEW JOSEPH ,  FULLERTON ERIC EDWARD ,  GURNEY BRUCE ALVIN ,  ROSEN HAL JERVIS ,  SCHABES MANFRED ERNST

IPC: G11B5/708 ,  C23C28/00 ,  C23C28/02 ,  G11B5/64 ,  G11B5/65 ,  G11B5/66 ,  G11B5/673 ,  G11B5/738 ,  H01F10/26 ,  C23C14/14 ,  C23C14/16 ,  G11B5/62 ,  G11B5/84

Abstract: A magnetic recording medium for data storage uses a magnetic recording layer having at least two ferromagnetic films antiferromagnetically coupled together across a nonferromagnetic spacer film. The magnetic moments of the two antiferromagnetically-coupled films are oriented antiparallel, and thus the net remanent magnetisation-thickness product (Mrt) of the recording layer is the difference in the Mrt values of the two ferromagnetic films. This reduction in Mrt is accomplished without a reduction in the thermal stability of the recording medium because the volumes of the grains in the antiferromagnetically-coupled films add constructively. In a magnetic recording rigid disk application, the magnetic layer comprises two ferromagnetic films, each a granular film of a sputter deposited coPtCrB alloy, separated by a Ru spacer film having a thickness to maximise the antiferromagnetic exchange coupling between the two CoPtCrB films. One of the ferromagnetic films is made thicker than the other, but the thicknesses are chosen so that the net moment in zero applied magnetic field is low, but nonzero. In general the first and second ferromagnetic films are made of a material selected from Co, Fe, Ni and their alloys. Apart from ruthenium the spacer film may be formed of Cr, Rh, Ir, Cu and their alloys. The medium may be in the form of a disk which has an underlayer on the substrate and a protective overcoat formed on the magnetic recording layer.