Abstract: A current-perpendicular-to-the-plane (CPP) magnetoresistive sensor or read head has a magnetic shield geometry that covers the side walls of the sensor structure to prevent side reading caused by magnetic flux entering from adjacent data tracks. The shield geometry includes a bottom shield with a substantially planar surface and a specially shaped top shield. The top shield has substantially vertical portions generally parallel to the side walls of the sensor structure, a horizontal top portion over the trackwidth region of the sensor, and horizontal side portions formed over the portions of the bottom shield on either side of the sensor structure. The insulating gap material that separates the bottom and top shields is in contact with the horizontal portions of the bottom shield and the side walls of the sensor structure.

Abstract: A flux guided magnetic tunnel junction head includes a ferromagnetic pinned layer having an active region with a front edge recessed from a sensing surface, and a non-active region located between the sensing surface and the active region. The non-active region of the ferromagnetic pinned layer is rendered substantially non-conducting by chemically processing the ferromagnetic material of the ferromagnetic pinned layer in this region. The flux guided MTJ head also includes a ferromagnetic free layer having a front edge substantially coplanar with a sensing surface. The ferromagnetic free layer can function as a flux guide to direct magnetic flux from a recording medium to the tunnel junction. The location of the front edge of the ferromagnetic pinned layer prevents any shorting of the flux guided MTJ head occurring when the head is lapped at the sensing surface.

Abstract: A flux guided magnetic tunnel junction head includes a ferromagnetic pinned layer having an active region with a front edge recessed from a sensing surface, and a non-active region located between the sensing surface and the active region. The non-active region of the ferromagnetic pinned layer is rendered substantially non-conducting by chemically processing the ferromagnetic material of the ferromagnetic pinned layer in this region. The flux guided MTJ head also includes a ferromagnetic free layer having a front edge substantially coplanar with a sensing surface. The ferromagnetic free layer can function as a flux guide to direct magnetic flux from a recording medium to the tunnel junction. The location of the front edge of the ferromagnetic pinned layer prevents any shorting of the flux guided MTJ head occurring when the head is lapped at the sensing surface.

Abstract: A current-perpendicular-to-the-plane (CPP) magnetoresistive sensor or read head has a magnetic shield geometry that covers the side walls of the sensor structure to prevent side reading caused by magnetic flux entering from adjacent data tracks. The shield geometry includes a bottom shield with a substantially planar surface and a specially shaped top shield. The top shield has substantially vertical portions generally parallel to the side walls of the sensor structure, a horizontal top portion over the trackwidth region of the sensor, and horizontal side portions formed over the portions of the bottom shield on either side of the sensor structure. The insulating gap material that separates the bottom and top shields is in contact with the horizontal portions of the bottom shield and the side walls of the sensor structure.

Abstract: A high-aspect ratio resist profile is obtained using a development process wherein a mixture of an alcohol and water is used as the developer. The alcohol/water mixture is non-toxic, and does not cause excess swelling and cracking of the resist during the development process.

Abstract: A method for producing a magnetic structure, such as a thin film magnetic head, in which the magnetic and electrical characteristics of magnetic material are tailored to produce magnetic and electrical characteristics in selected localized areas of the magnetic material. In a specific embodiment, the structure comprises a layer of magnetic material having an overlayer and an underlayer, and the magnetic characteristics of the material are modified by rapid thermal annealing.

Abstract: An improved spin valve (SV) magnetoresistive element has its free ferromagnetic layer in the form of a central active region with defined edges and 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 element 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.

Abstract: In a magnetoresistive (MR) read sensor in which the MR layer is transversely biased by a soft magnetic layer separated from the MR layer by a nonmagnetic spacer layer an antiferromagnetic stabilization layer of NiO provides a stabilizing exchange-coupled magnetic field to the transverse bias layer insuring that the transverse bias layer is fully saturated in a preferred direction during sensor operation.

Abstract: A method for producing a magnetic structure, such as a thin film magnetic head, in which the magnetic and electrical characteristics of magnetic material are tailored to produce magnetic and electrical characteristics in selected localized areas of the magnetic material. In a specific embodiment, the structure comprises a layer of magnetic material having an overlayer and an underlayer, and the magnetic characteristics of the material are modified by rapid thermal annealing.

Abstract: In a magnetoresistive (MR) read sensor in which the MR layer is transversely biased by a soft magnetic layer separated from the MR layer by a nonmagnetic spacer layer an antiferromagnetic stabilization layer of NiO provides a stabilizing exchange-coupled magnetic field to the transverse bias layer insuring that the transverse bias layer is fully saturated in a preferred direction during sensor operation.

Abstract: A magnetoresistive (MR) read transducer assembly having passive end regions separated by a central active region, and a method of fabricating it. Layers of a first biasing material and a nonmagnetic decoupling spacer material are deposited on a substrate, then covered by a mask only in the central region. By etching or ion milling, those parts of the layers not covered by the mask are removed to define a transverse biasing means in the central region and define the passive end regions. With the same mask remaining in place, a conductive material and exchange layer comprising a second biasing material are deposited over all regions. The mask is removed to define and provide conductor leads and longitudinal biasing means only in the end regions. MR material is thereafter deposited as a continuous thin film in direct contact with the central region containing the transverse biasing means and in direct contact with the end regions containing the longitudinal biasing means.

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.

Abstract: A rotary actuator disk drive uses substantially identical dual-element inductive write/magnetoresistive read transducers for both the top and bottom disk surfaces. There is no requirement that the read elements be mechanically offset from the write elements, as is typically the case in rotary actuator disk drives due to the head-to-track skew caused by the inherent nonlinear path of the heads across the data tracks. The transducers are supported on the trailing ends of the head carriers in such a manner that the geometric centers of the read and write elements are aligned without any mechanical offset. Sense currents of opposite polarity are provided to the magnetoresisitve read elements adjacent the top and bottom disk surfaces to shift the magnetic centers of the top and bottom read elements in opposite directions relative to their geometric centers.

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.

Abstract: A magnetoresistive (MR) read transducer in which a layered structure comprising an MR layer, an antiferromagnetic material in direct contact with the MR layer and a thin layer of interdiffusion material in contact with the layer of antiferromagnetic material is subjected to a heating process to a temperature within a chosen temperature for a chosen time to form a magnetic interface between the antiferromagnetic material the MR layer. The magnetic interface produces a high level of exchange bias with the MR layer.

Abstract: An MR read transducer having passive end regions separated by a central active region comprises an MR layer made from a material having a low uniaxial magnetic anisotropy. A soft magnetic bias layer is adjacent to but spaced from the MR layer in the central region only, and the soft magnetic bias layer is made from a material having a high uniaxial magnetic anisotropy. A longitudinal bias is produced directly in each of the end regions only, and the means for producing the longitudinal bias comprise a layer made from a material having a high uniaxial magnetic anisotropy. Control of the uniaxial anisotropy can be achieved by choosing materials of appropriate magnetostriction or intrinsic uniaxial anisotropy.

Abstract: A method and device for use in measurement and compensation of nonlinear bitshift in nonlinear communication media such as magnetic and optical recording devices. The method and device are based on special bit patterns constructed to eliminate at least one harmonic of the fundamental frequency of the data pattern if all bits are communicated without any nonlinear bitshift. The presence of nonlinear bitshift is manifested by the appearance of the harmonic. By measuring the magnitude of the harmonic, the amount of nonlinear bitshift is determined, and compensation adjustment is then used to offset its effect on the data detection scheme.

Abstract: A magnetoresistive (MR) read transducer in which a layered structure comprising an MR layer, an antiferromagnetic material in direct contact with the MR layer and a thin layer of interdiffusion material in contact with the layer of antiferromagnetic material is subjected to a heating process to a temperature within a chosen temperature for a chosen time to form a magnetic interface between the antiferromagnetic material the MR layer. The magnetic interface produces a high level of exchange bias with the MR layer.

Abstract: An improved magnetoresistive (MR) read transducer in which a layered structure comprising an antiferromagnetic layer in direct contact with an MR layer is subjected to a thermal annealing process by heating the structure to a temperature within a chosen range for a chosen time so that a new ternary antiferromagnetic alloy is formed by diffusion. The ternary antiferromagnetic alloy has a high value of exchange bias which is less temperature sensitive. In a specific embodiment in which the MR layer is NiFe and the antiferromagnetic layer is FeMn, the ternary alloy formed by heating the structure to a temperature within the range of 260.degree. C. to 350.degree. C. for 50 to 20 hours has a room temperature exchange bias field with NiFe of about 50 Oersted and an ordering temperature which exceeds 300.degree. C.

Abstract: A magnetoresistive (MR) read transducer assembly in which the thin film MR layer is longitudinally biased only in the end regions by exchange bias developed by a thin film of antiferromagnetic material 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 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 are connected to the MR layer within the central region to define a detection region so that signal output means connected to the conductive elements can determine the resistance changes in the detection region of the MR layer as a function of the fields which are intercepted by the MR layer.