Abstract: A magnetoresistive sensor having a self biased free layer. The free layer is constructed upon an underlayer that has been treated by a surface texturing process that configures the underlayer with an anisotropic roughness that induces a magnetic anisotropy in the free layer. The treated layer underlying the free layer can be a spacer layer sandwiched between the free layer and pinned layer or can be a separate underlayer formed opposite the spacer layer. Alternatively, the texturing of an underlayer can be used to induce a magnetic anisotropy in a bias layer that is separated from the free layer by an orthogonal coupling layer. This self biasing of the free layer induced by texturing can also be used in conjunction with biasing from a hard-bias structure.

Abstract: A magnetoresistive sensor having a hard bias layer with an engineered magnetic anisotropy in a direction substantially parallel with the medium facing surface. The hard bias layer may be constructed of CoPt, CoPtCr or some other magnetic material and is deposited over an underlayer that has been ion beam etched. The ion beam etch has been performed at an angle with respect to normal in order to induce anisotropic roughness on its surface for example in form of oriented ripples or facets. The anisotropic roughness induces a uniaxial magnetic anisotropy substantially parallel to the medium facing surface in the hard magnetic bias layers deposited there over.

Abstract: A magnetoresistive sensor having a hard magnetic pinning layer with an engineered magnetic anisotropy in a direction substantially perpendicular to the medium facing surface. The hard magnetic pinning layer may be constructed of CoPt, CoPtCr, or some other magnetic material and is deposited over an underlayer that has been ion beam etched. The ion beam etch has been performed at an angle with respect to normal in order to induce anisotropic roughness for example in form of oriented ripples or facets oriented along a direction parallel to the medium facing surface. The anisotropic roughness induces a strong uniaxial magnetic anisotropy substantially perpendicular to the medium facing surface in the hard magnetic pinning layer deposited there over.

Abstract: A magnetoresistive sensor having an in stack bias layer with an engineered magnetic anisotropy in a direction parallel with the medium facing surface. The in-stack bias layer may be constructed of CoPt, CoPtCr or some other magnetic material and is deposited over an underlayer that has been ion beam etched. The ion beam etch has been performed at an angle with respect to normal in order to form anisotropic roughness in form of oriented ripples or facets. The anisotropic roughness induces a uniaxial magnetic anisotropy substantially parallel to the medium facing surface in the hard magnetic in-stack bias layer deposited thereover.

Abstract: A current perpendicular to plane dual giant magnetoresistive sensor (dual CPP GMR sensor) that prevents spin torque noise while having high dR/R performance. The sensor has a design that maximizes the GMR effect (dR/R) by providing a pinned layer structure that maximizes the positive GMR contribution of the AP2 layer (or magnetic layer closest to the spacer layer) while minimizing the negative GMR contribution of the AP1 layer (or layer furthest from the spacer layer). The pinned layer structure includes an AP1 layer that includes a thin CoFe layer that is exchange coupled with an IrMn or IrMnCr AFM layer and has two or more Co layers with a spin blocking layer sandwiched between them. The use of the Co layers and the spin blocking layer in the AP1 layer minimizes the negative contribution of the AP1 layer. The AP2 layer has a plurality of CoFe layers with nano-layers such as Cu sandwiched between the CoFe layers.

Abstract: An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

Abstract: An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

Abstract: An exchange-coupled magnetic structure of a cobalt-ferrite layer adjacent a magnetic metal layer is used in magnetorestive sensors, such as spin valves or tunnel junction valves. The exchange-coupled magnetic structure is used in a pinning structure pinning the magnetization of a ferromagnetic pinned layer, or in an AP pinned layer. A low coercivity ferrite may be used in an AP free layer. Cobalt-ferrite layers may be formed by co-sputtering of Co and Fe in an oxygen/argon gas mixture, or by sputtering of a CoFe2 composition target in an oxygen/argon gas mixture. Alternatively, the cobalt-ferrite layer may be formed by evaporation of Co and Fe from an alloy source or separate sources along with a flux of oxygen atoms from a RF oxygen atom beam source. Magnetoresistive sensors including cobalt-ferrite layers have small read gaps and produce large signals with high efficiency.

Abstract: An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

Abstract: An exchange-coupled magnetic structure of a cobalt-ferrite layer adjacent a magnetic metal layer is used in magnetorestive sensors, such as spin valves or tunnel junction valves. The exchange-coupled magnetic structure is used in a pinning structure pinning the magnetization of a ferromagnetic pinned layer, or in an AP pinned layer. A low coercivity ferrite may be used in an AP free layer. Cobalt-ferrite layers may be formed by co-sputtering of Co and Fe in an oxygen/argon gas mixture, or by sputtering of a CoFe2 composition target in an oxygen/argon gas mixture. Alternatively, the cobalt-ferrite layer may be formed by evaporation of Co and Fe from an alloy source or separate sources along with a flux of oxygen atoms from a RF oxygen atom beam source. Magnetoresistive sensors including cobalt-ferrite layers have small read gaps and produce large signals with high efficiency.

Abstract: An exchange-coupled magnetic structure of a cobalt-ferrite layer adjacent a magnetic metal layer is used in magnetorestive sensors, such as spin valves or tunnel junction valves. The exchange-coupled magnetic structure is used in a pinning structure pinning the magnetization of a ferromagnetic pinned layer, or in an AP pinned layer. A low coercivity ferrite may be used in an AP free layer. Cobalt-ferrite layers may be formed by co-sputtering of Co and Fe in an oxygen/argon gas mixture, or by sputtering of a CoFe2 composition target in an oxygen/argon gas mixture. Alternatively, the cobalt-ferrite layer may be formed by evaporation of Co and Fe from an alloy source or separate sources along with a flux of oxygen atoms from a RF oxygen atom beam source. Magnetoresistive sensors including cobalt-ferrite layers have small read gaps and produce large signals with high efficiency.

Abstract: A CPP magnetoresistive sensor with a spacer layer made of a heterogeneous material, which is composed of conductive grains within a highly resistive matrix, has a high resistance. The conductive grains are typically made of a conductive element or alloy that can operate as a GMR spacer material. The highly resistive matrix is typically made of a highly resistive or insulating element, alloy or compound that will hinder the flow of electrons. The sensing electrical current is passed through the conductive grains, which are typically made of the same material as GMR spacers, so the GMR is maintained even though the overall resistance is increased.

Abstract: A method for writing data on a magnetic recording medium includes providing a magnetic recording layer having at least two ferromagnetic films antiferromagnetically coupled together across a nonferromagnetic spacer film, with one of the ferromagnetic films having a greater magnetic moment than the other. A positive write field is applied to a first region to align the moments of both ferromagnetic films with the positive field, and then a negative write field is applied to an adjacent region to align the moments of both ferromagnetic films with the negative field. When the medium is moved away from the write fields, the moment of the ferromagnetic film with the lesser moment in each region flips to be antiparallel to the moment of the other ferromagnetic film in its region. The result is that the adjacent regions become adjacent magnetized domains with the transition between the domains representative of the written data.

Abstract: In a spin valve, at least one AP pinned sublayer and/or one AP free sublayer comprise high resistivity alloys of the type AB, wherein A is selected from the group consisting of CoFe, NiFe, and CoFeNi, and B is selected from the group consisting of B, Ta, Nb, Zr, and/or Hf. The resistivity value of the highly resistive layer is typically between about 30 &mgr;&OHgr;-cm and 100 &mgr;&OHgr;-cm. The highly resistive layers reduce the shunting of the sense current away from the rest of the structure, and prevent electrons from being shunted away from the active region of the spin valve and, thus, reducing &Dgr;R/R. The spin valve of this layered structure can increase the overall sheet resistance and optimize the &Dgr;R/R value of the spin valve.

Abstract: A magnetic sensor which detects an external magnetic field with the aid of a ferromagnetic free layer having a magnetic moment responsive to the external magnetic field. The magnetic sensor has an antiferromagnetic layer which is magnetically exchange-coupled to the free layer to produce an exchange bias field He which acts on the free layer to bias its magnetic moment along a certain orientation such as the transverse direction. The additional exchange bias field He is used in balancing a total transverse internal magnetic field Ht which is due to other fields generated by the sensor itself. The value of exchange bias field He is set, e.g., by selecting a certain thickness and a certain composition of the antiferromagnetic layer. The magnetic sensor of the invention can also have a non-magnetic spacer layer interposed between the free layer and the antiferromagnetic layer or be in contact with the free layer.

Abstract: An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

Abstract: The current invention provides for magnetic sensor devices with reduced gap thickness and improved thermal conductivity. Gap structures of the current invention are integrated in laminated Magneto-Resistive and Spin-Valve sensors used in magnetic data storage systems. The gap structures are produced by depositing metal layers and oxidizing portions of or all of the metal layers to form thin high quality oxidized metal dielectric separator layers. The oxidized metal layer provides for excellent electrical insulation of the sensor element and any remaining metallic portions of the metal layers provide a thermally conducting pathway to assist the dissipation of heat generated by the sensor element. Because of the combined qualities of electrical insulation and thermal conductivity, magnetic sensor devices of this invention can be made with thinner gap structures and operated at higher drive currents.

Abstract: A CPP magnetoresistive sensor with a spacer layer made of a heterogeneous material, which is composed of conductive grains within a highly resistive matrix, has a high resistance. The conductive grains are typically made of a conductive element or alloy that can operate as a GMR spacer material. The highly resistive matrix is typically made of a highly resistive or insulating element, alloy or compound that will hinder the flow of electrons. The sensing electrical current is passed through the conductive grains, which are typically made of the same material as GMR spacers, so the GMR is maintained even though the overall resistance is increased.

Abstract: An exchange-coupled magnetic structure of a cobalt-ferrite layer adjacent a magnetic metal layer is used in magnetorestive sensors, such as spin valves or tunnel junction valves. The exchange-coupled magnetic structure is used in a pinning structure pinning the magnetization of a ferromagnetic pinned layer, or in an AP pinned layer. A low coercivity ferrite may be used in an AP free layer. Cobalt-ferrite layers may be formed by co-sputtering of Co and Fe in an oxygen/argon gas mixture, or by sputtering of a CoFe2 composition target in an oxygen/argon gas mixture. Alternatively, the cobalt-ferrite layer may be formed by evaporation of Co and Fe from an alloy source or separate sources along with a flux of oxygen atoms from a RF oxygen atom beam source. Magnetoresistive sensors including cobalt-ferrite layers have small read gaps and produce large signals with high efficiency.

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.