公开(公告)号：MY107672A

公开(公告)日：1996-05-30

申请号：MYPI19912080

申请日：1991-11-11

Applicant: IBM

Inventor： DENNIS RICHARD WILHOIT ,  STEVEN EUGENE LAMBERT ,  STUART STEPHEN PAPWORTH PARKIN ,  BRUCE ALVIN GURNEY ,  DANIELE MAURI ,  VIRGIL SIMON SPERIOSU ,  BERNARD DIENY

IPC: G01R33/06 ,  G01R33/09 ,  G11B5/00 ,  G11B5/39

Abstract: A MAGNETORESISTIVE (MR) SENSOR COMPRISING A FIRST AND A SECOND THIN FILM LAYER OF A MAGNETIC MATERIAL (12,16) SEPARATED BY A THIN FILM LAYER OF A NON-MAGNETIC METALLIC MATERIAL (14). THE FIRST FERROMAGNETIC LAYER (12) IS MAGNETICALLY SOFT. THE MAGNETIZATION DIRECTION OF THE FIRST LAYER OF MAGNETIC MATERIAL (12) IS SET SUBSTANTIALLY PERPENDICULAR TO THE MAGNETIZATION OF THE SECOND LAYER OF MAGNETIC MATERIAL (16) AT ZERO APPLIED FIELD, AND THE MAGNETIZATION DIRECTION OF THE SEOCND LAYER OF MAGNETIC MATERIAL (16) IS FIXED. A CURRENT FLOW IS PRODUCED THROUGH THE MR SENSOR, AND THE VARIATIONS IN VOLTAGE ACROSS THE MR SENSOR ARE SENSED DUE TO CHANGES IN RESISTANCE OF THE MR SENSOR PRODUCED BY ROTATION OF THE MAGNETIZATION IN THE FIRST LAYER OF MAGNETIC MATERIAL (12) AS A FUNCTION OF THE MAGNETIC FIELD BEING SENSED. THE VARIATION OF THE RESISTANCE WITH THE ANGLE BETWEEN THE MAGNETIZATION OF THE FIRST AND SECOND LAYERS OF MAGNETIC MATERIAL HAS BEEN DEFINED AS THE SPIN VALVE (SV) EFFECT. IT IS ALSO SHOWN THAT, BY A SUITABLE DIRECTION OF THE CURRENT WITH RESPECT TO THE FIXED MAGNETIZATION, THE (SV) MAGNETORESISTANCE CAN BE ADDED CONSTRUCTIVELY TO THE USUAL ANISOTROPIC MAGNETORESISTANCE. (FIG.5)

公开(公告)号：SG87011A1

公开(公告)日：2002-03-19

申请号：SG1998004218

申请日：1998-10-16

Applicant: IBM

Inventor： ROBERT EDWARD FONTANA JR ,  STUART STEPHEN PAPWORTH PARKIN ,  CHING HWA TSANG ,  MASON LAMAR WILLIAMS

IPC: G11B5/39 ,  G11B5/33

Abstract: A magnetic tunnel junction (MTJ) magnetoresistive read head (25) for a magnetic recording system has the MTJ sensing or free ferromagnetic layer (132) also functioning as a flux guide to direct magnetic flux from the magnetic recording medium (16) to the tunnel junction. The MTJ fixed ferromagnetic layer (118) and the MTJ tunnel barrier layer (120) have their front edges substantially coplanar with the sensing surface (200) of the head (25). Both the fixed and free ferromagnetic layers (118, 132) are in contact with opposite surfaces of the MTJ tunnel barrier layer (120) but the free ferromagnetic layer extends beyond the back edge (212, 208) of either the tunnel barrier layer or the fixed ferromagnetic layer, whichever back edge is closer to the sensing surface (200). This assures that the magnetic flux is non-zero in the tunnel junction region. The magnetization direction (119) of the fixed ferromagnetic layer (118) is fixed in a direction generally perpendicular to the sensing surface and thus to the magnetic recording medium (16), preferably by interfacial exchange coupling with an antiferromagnetic layer (116). The magnetization direction (133) of the free ferromagnetic layer (132) is aligned in a direction generally parallel to the surface of the medium (16) in the absence of an applied magnetic field and is free to rotate in the presence of applied magnetic fields from the medium. A layer of high coercivity hard magnetic material adjacent the sides of the free Ferromagnetic layer (132) longitudinally biases the magnetization of the free ferromagnetic layer in the preferred direction.

公开(公告)号：SG111304A1

公开(公告)日：2005-05-30

申请号：SG200406873

申请日：2004-09-24

Applicant: IBM

Inventor： STUART STEPHEN PAPWORTH PARKIN

IPC: G11C11/15 ,  G11C11/14 ,  G11C19/08 ,  H01L21/8246 ,  H01L27/105 ,  H01L43/08

Abstract: A data storage device includes a unpatterned magnetic film having data regions in which to store data. A track is disposed in proximity to the magnetic film, such that the track selectively defines a shiftable magnetic domain wall. In order to select a data bit that is stored in one of the data regions of the magnetic film, a fringing field of the magnetic domain wall in the track is used to selectively change a direction of a magnetic moment in the data region.

公开(公告)号：SG86336A1

公开(公告)日：2002-02-19

申请号：SG1998003949

申请日：1998-10-01

Applicant: IBM

Inventor： STUART STEPHEN PAPWORTH PARKIN

IPC: G11B5/39 ,  G11C11/15 ,  G11C11/16 ,  H01F10/32 ,  H01L43/08 ,  G11B5/127

Abstract: An improved magnetic tunnel junction (MTJ) device for use in a magnetic recording read head or in a magnetic memory storage cell is comprised of two ferromagnetic layers, a "hard" or "fixed" ferromagnetic layer and a sensing or "free" ferromagnetic layer, which are separated by a thin insulating tunnelling layer. Each of the ferromagnetic layers is a multilayer formed from two thinner ferromagnetic films coupled antiferromagnetically to one another across a thin antiferromagnetically coupling film. The antiferromagnetically coupling film is chosen, with regard to material composition and thickness, so that it causes the two ferromagnetic films which sandwich it to have their magnetic moments arranged antiparallel to one other in the absence of external magnetic fields. The magnetic moments of the fixed ferromagnetic multilayer and free ferromagnetic layer can be chosen to be arbitrarily small by making the two ferromagnetic films comprising each of them to have substantially the same magnetic moment. Thus the dipole fields from each of the fixed and free ferromagnetic multilayers can be minimized, thereby reducing the magnetic interaction between the fixed ferromagnetic multilayer and the free ferromagnetic multilayer.