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    Thin film merged MR head with aligned pole tips
    11.
    发明专利
    Thin film merged MR head with aligned pole tips 未知

    公开(公告)号：SG28470A1

    公开(公告)日：1996-04-01

    申请号：SG1995000073

    申请日：1995-03-08

    Applicant: IBM

    Inventor： TSANG CHING HWA ,  LO JYH-SHUEY JERRY ,  KROUNBI MOHAMAD TOWFIK

    IPC: G11B5/31 ,  G11B5/39 ,  G11B5/127

    Abstract: A merged MR head is provided which has vertically aligned sidewalls so as to minimize side-fringing and improve off-track performance. The bottom pole piece P1, which comprises the second shield layer S2 of the read head, has a pedestal pole tip with a short length dimension. A pedestal pole tip with a length as short as two times the length of the gap layer G optimally minimizes the sidewriting and improves off-track performance. The bottom pole tip structure of the write head is constructed by ion beam milling using the top pole tip structure as a mask. The ion beam milling is directed at an angle to the sidewalls of the top pole tip structure which causes the bottom pole tip structure to be milled with sidewalls which align with the top pole tip structure. The ion beam milling can comprise two angled beams, either sequentially or simultaneously, the first beam performing primarily a cutting operation and some clean up work while the second beam primarily conducts clean up work of the redeposition of the debris caused by the cutting. In another embodiment, a single angled ion beam can be employed, provided its angle is within a particular range.

    MAGNETIC TUNNEL JUNCTION MAGNETORESISTIVE READ HEAD WITH LONGITUDINAL AND TRANSVERSE BIAS
    15.
    发明专利
    MAGNETIC TUNNEL JUNCTION MAGNETORESISTIVE READ HEAD WITH LONGITUDINAL AND TRANSVERSE BIAS 未知

    公开(公告)号：SG82614A1

    公开(公告)日：2001-08-21

    申请号：SG1999002429

    申请日：1999-05-13

    Applicant: IBM

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

    IPC: G01R33/06 ,  G11B5/39

    Abstract: A magnetic tunnel junction magnetoresistive read head has one fixed ferromagnetic layer and one generally rectangularly shaped sensing ferromagnetic layer on opposite sides of the tunnel barrier layer, and a biasing ferromagnetic layer located around the side edges and back edges of the sensing ferromagnetic layer. An electrically insulating layer separates the biasing layer from the edges of the sensing layer. The biasing layer is a continuous boundary biasing layer that has side regions and a back region to surround the three edges of the sensing layer. When the biasing layer is a single layer with contiguous side and back regions its magnetic moment can be selected to make an angle with the long edges of the sensing layer. In this manner the biasing layer provides both a transverse bias field to compensate for transverse ferromagnetic coupling and magnetostatic coupling fields acting on the sensing layer to thus provide for a linear response of the head and a longitudinal bias field to stabilize the head. The biasing layer may also be formed with discrete side regions and a back region. The discrete side regions may have a magnetic moment oriented in a different direction from the moment of the back region in order to provide the correct combination of transverse and longitudinal bias fields.

    MAGNETORESISTIVE READ TRANSDUCER ASSEMBLY
    18.
    发明专利
    MAGNETORESISTIVE READ TRANSDUCER ASSEMBLY 未知

    公开(公告)号：HK96390A

    公开(公告)日：1990-11-30

    申请号：HK96390

    申请日：1990-11-22

    Applicant: IBM

    Inventor： TSANG CHING HWA

    IPC: G01R33/09 ,  G11B5/39 ,  H01L43/08

    Abstract: A magnetoresistive (MR) read transducer assembly comprises a thin film MR layer (10) which is longitudinally biased only in the end regions (12) by exchange bias developed by a thin film of antiferro­magnetic material (16) that is deposited in direct contact with the MR layer in the end regions. The longitudinal bias is of a level suffi­cient to maintain the end regions of the MR layer in a single domain state and thereby induce a single domain state in the central region (14) of the MR layer. Transverse bias is produced within the central region of the MR layer of a level sufficient to maintain that region of the MR layer in a linear response mode. Spaced conductive elements (18,20) are connected to the MR layer within the central region to define a detection region so that sensing means connected to the con­ductive elements can determine the resistance changes in the detection region of the MR layer resulting from the magnetic fields intercepted by the MR layer.

    19.
    发明专利
    未知

    公开(公告)号：AT221999T

    公开(公告)日：2002-08-15

    申请号：AT94119895

    申请日：1994-12-16

    Applicant: IBM

    Inventor： COFFEY KEVIN ROBERT ,  FONTANA ROBERT EDWARD ,  HOWARD JAMES KENT ,  HYLTON TODD LANIER ,  PARKER MICHAEL ANDREW ,  TSANG CHING HWA

    IPC: G01R33/09 ,  G11B5/39 ,  H01L43/10

    Abstract: A magnetoresistive read sensor incorporates a multilayer sensing element formed of one or more magnetoresistive elements in a planar array, each magnetoresistive element having a multilayer structure of at least two ferromagnetic layers separated by a nonmagnetic layer. The ferromagnetic layers are coupled antiferromagnetically by magnetostatic coupling at opposing edges of the ferromagnetic layers. A bias layer separated from the magnetoresistive sensing element by a spacer layer provides a magnetic field to bias the magnetoresistive sensing element at a desired non-signal point for linear response. The magnetoresistive sensing element is formed by alternatively depositing layers of ferromagnetic material and layers of nonmagnetic material on a substrate and then patterning the resulting structure using photolithographic techniques to provide a planar array of magnetoresistive elements. A conductive layer is deposited over the array filling in the spaces separating the magnetoresistive elements to provide electrical conductivity between the elements in the plane of the structure.

    Magnetic tunnel junction magnetoresistive read head with sensing layer as flux guide
    20.
    发明专利
    Magnetic tunnel junction magnetoresistive read head with sensing layer as flux guide 未知

    公开(公告)号：SG67573A1

    公开(公告)日：1999-09-21

    申请号：SG1998004207

    申请日：1998-10-14

    Applicant: IBM

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

    IPC: G11B5/39 ,  G11B5/40 ,  G11B5/33

    Abstract: A magnetic tunnel junction (MTJ) magnetoresistive read head for a magnetic recording system has the MTJ sensing or free ferromagnetic layer also functioning as a flux guide to direct magnetic flux from the magnetic recording medium to the tunnel junction. The MTJ fixed ferromagnetic layer has its front edge recessed from the sensing surface of the head. Both the fixed and free ferromagnetic layers are in contact with opposite surfaces of the MTJ tunnel barrier layer but the free ferromagnetic layer extends beyond the back edge of either the tunnel barrier layer or the fixed ferromagnetic layer, whichever back edge is closer to the sensing surface. This assures that the magnetic flux is non-zero in the tunnel junction region. The magnetization direction of the fixed ferromagnetic layer is fixed in a direction generally perpendicular to the sensing surface and thus to the magnetic recording medium, preferably by interfacial exchange coupling with an antiferromagnetic layer. The magnetization direction of the free ferromagnetic layer is aligned in a direction generally parallel to the surface of the medium 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 longitudinally biases the magnetization of the free ferromagnetic layer in the preferred direction.

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