3.
    发明专利
    未知

    公开(公告)号:DE69420789T2

    公开(公告)日:2000-04-27

    申请号:DE69420789

    申请日:1994-07-04

    Applicant: IBM

    Abstract: A magnetoresistive (MR) read transducer is disclosed having passive end regions separated by a central active region in which an MR layer is formed over substantially only the central active region and in which a magnetic bias layer is formed in each passive end region. In one embodiment, each of the magnetic bias layers includes a layer of ferromagnetic material and a layer of antiferromagnetic material overlaying and in contact with the ferromagnetic layer to provide an exchange-coupled magnetic bias field. Alternatively a hard magnetic material is used to form the biasing layer. Each of the magnetic bias layers form an abutting junction having magnetic and electrical continuity with the MR layer to produce a stable longitudinal magnetic bias field in the transducer, even when the length of the active region is small to accommodate small track widths.

    4.
    发明专利
    未知

    公开(公告)号:DE69326308T2

    公开(公告)日:2000-04-20

    申请号:DE69326308

    申请日:1993-11-15

    Applicant: IBM

    Abstract: A magnetoresistive sensor based on the spin valve effect in which a component of the read element resistance varies as the cosine of the angle between the magnetization directions in two adjacent magnetic layers is described. The sensor read element includes two adjacent ferromagnetic layers separated by a non-magnetic metallic layer, the magnetic easy axis of each of the ferromagnetic layers being aligned along the longitudinal axis of the ferromagnetic layers and perpendicular to the trackwidth of an adjacent magnetic storage medium. The sense current flowing in the sensor element generates a bias field which sets the direction of magnetization in each ferromagnetic layer at an equal, but opposite, angle theta with respect to the magnetic easy axis thus providing an angular separation of 2 theta in the absence of an applied magnetic signal. The magnetizations of both ferromagnetic layers are responsive to an applied magnetic field to change their angular separation by an amount 2 delta theta .

    5.
    发明专利
    未知

    公开(公告)号:BR9502918A

    公开(公告)日:1996-02-27

    申请号:BR9502918

    申请日:1995-06-23

    Applicant: IBM

    Abstract: The present invention provides an improved spin valve (SV) magnetoresistive sensor, which has its free ferromagnetic layer in the form of a central active region with defined edges and has a separate layer providing end regions that are contiguous with and abut the edges of the central active region. A layer of antiferromagnetic material, preferably a nickel-manganese (Ni-Mn) alloy, is formed on and in contact with the ferromagnetic material in the end regions for exchange coupling with the end regions to provide them with a longitudinal bias of their magnetizations. The pinned ferromagnetic layer in the SV sensor is pinned by exchange coupling with a different layer of antiferromagnetic material, preferably an iron-manganese (Fe-Mn) alloy. This material has a substantially different Neel temperature from that of the antiferromagnetic material on the end regions. The process for making the SV sensor includes heating to different predetermined temperatures in the presence of an applied magnetic field to orient the magnetizations of the free and pinned layers in the proper direction. The SV sensor may be used for reading data in magnetic recording systems.

    6.
    发明专利
    未知

    公开(公告)号:DE69431149T2

    公开(公告)日:2003-05-28

    申请号:DE69431149

    申请日:1994-12-16

    Applicant: IBM

    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.

    7.
    发明专利
    未知

    公开(公告)号:DE69431149D1

    公开(公告)日:2002-09-12

    申请号:DE69431149

    申请日:1994-12-16

    Applicant: IBM

    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.

    9.
    发明专利
    未知

    公开(公告)号:DE69204869D1

    公开(公告)日:1995-10-26

    申请号:DE69204869

    申请日:1992-01-16

    Applicant: IBM

    Abstract: An integrated inductive write, magnetoresistive (MR) read thin film magnetic head comprising an open magnetic yoke having outside legs each having a winding thereon and a central leg having an opening across which the MR element is coupled. The outer legs are overlapped at one end to form confronting pole pieces having a transducing gap between the pole pieces, and the central leg is positioned between the pole pieces at one end and joined with the outer legs at the other end to form a symmetrical magnetic yoke structure. The windings are wound in a direction so that the flux produced by equally energizing the windings is equal and opposite in each of the outside legs, is additive at the transducing gap between the pole pieces, and produces no net flux through the central leg.

    10.
    发明专利
    未知

    公开(公告)号:DE69534013T2

    公开(公告)日:2006-05-04

    申请号:DE69534013

    申请日:1995-10-27

    Applicant: IBM

    Abstract: A magnetic field sensor (10) uses four individual magnetoresistive spin valve elements (A,B,C,D) electrically connected in a bridge circuit. The spin valve elements (A,B,C,D) are lithographically formed on the same substrate with their free layers (36) having their magnetization axes parallel to one another. An electrically conductive fixing layer is formed on the substrate but is insulated from the spin valve elements. The application of current through the fixing conductor during fabrication of the field sensor fixes the direction of magnetization of two of the pinned layers (39) to be antiparallel to the direction of magnetization of the other two pinned layers (39). The bridge circuit (10) output voltage is responsive to an external magnetic field (4) in the plane of the sensor (10). By appropriate fixing of the direction of magnetization of the pinned layers (39) during sensor (10) fabrication, and appropriate connection to the input (20,22) and output leads (24,26), the bridge circuit output voltage is a measure of either the magnetic field or field gradient.

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