Abstract: A current-perpendicular-to-plane (CPP) magnetoresistance sensor and a method for forming a current-perpendicular-to-plane (CPP) magnetoresistance sensor. The method includes providing a ferromagnetic shield layer and disposing one or more seed layers on the ferromagnetic shield layer. The method also includes disposing a pinning layer on the one or more seed layers, wherein the pinning layer excludes PtMn, and disposing a pinned layer on the pinning layer. The shield layer, each of the one or more seed layers, the pinning layer, and the pinned layer are comprised of compounds having face-centered-cubic structures.

Abstract: A read sensor with a uniform longitudinal bias (LB) stack is proposed. The read sensor is a giant magnetoresistance (GMR) sensor used in a current-in-plane (CIP) or a current-perpendicular-to-plane (CPP) mode, or a tunneling magnetoresistance (TMR) sensor used in the CPP mode. The transverse pinning layer of the read sensor is made of an antiferromagnetic Pt—Mn, Ir—Mn or Ir—Mn—Cr film. In one embodiment of this invention, the uniform LB stack comprises a longitudinal pinning layer, preferable made of an antiferromagnetic Ir—Mn—Cr or Ir—Mn film, in direct contact with and exchange-coupled to sense layers of the read sensor. In another embodiment of the present invention, the uniform LB stack comprises the Ir—Mn—Cr or Ir—Mn longitudinal pinning layer exchange coupled to a ferromagnetic longitudinal pinned layer, and a nonmagnetic antiparallel-coupling spacer layer sandwiched between and the ferromagnetic longitudinal pinned layer and the sense layers.

Abstract: This invention provides a CPP TMR or GMR sensor with an amorphous ferromagnetic lower keeper layer and a crystalline ferromagnetic upper keeper layer. The amorphous ferromagnetic lower keeper layer strongly exchange-couples to an underlying antiferromagnetic pinning layer and planarizes its rough surface. The crystalline ferromagnetic upper keeper layer strongly antiparallel-couples to an adjacent ferromagnetic reference layer across a nonmagnetic spacer layer. The amorphous ferromagnetic lower keeper layer is preferably made of a Co—Fe—B alloy film with an Fe content high enough to ensure strong exchange-coupling to the underlying antiferromagnetic pinning layer, and with a B content high enough to ensure the formation of an amorphous phase for planarizing an otherwise rough surface due to the underlying antiferromagnetic pinning layer.

Abstract: A lead overlay design of a magnetic sensor is described with sensor and free layer dimensions such that the free layer is stabilized by the large demagnetization field due to the shape anisotropy. In one embodiment the giant magnetoresistive (GMR) effect under the leads is destroyed by removing the antiferromagnetic (AFM) and pinned layers above the free layer. The overlaid lead pads are deposited on the exposed spacer layer at the sides of the mask that defines the active region. In other embodiment a layer of electrically insulating material is deposited over the sensor to encapsulate it and thereby insulate it from contact with the hardbias structures. Various embodiments with self-aligned leads are also described. In a variation of the encapsulation embodiment, the insulating material is also deposited under the lead pads so the electrical current is channeled through the active region of the sensor and sidewall deposited lead pads.

Abstract: A method for achieving a nearly zero net magnetic moment of pinned layers in GMR sensors, such as Co—Fe/Ru/Co—Fe, is described. The method determines a thickness of the first pinned layer which will yield the desired net magnetic moment for the pinned layers. A series of test structures are deposited on a substrate such as glass. The test structures include the seed layers, pinning layers and pinned layers and have varying thicknesses of the first pinned layer. The compositions of the materials and the thicknesses of all of the other films remain constant. The net areal magnetic moment of each test structure is measured and plotted versus the thickness of the first pinned layer. The thickness of the first pinned layer which corresponds most closely to zero net areal magnetic moment is chosen as the design point for the sensor.

Abstract: A method of constructing a small trackwidth magnetorsesistive sensor by defining a trench between first and second hard bias layers and depositing the sensor into the trench.

Abstract: A narrow track-width magnetoresistive sensor by defining a trench formed between first and second hard bias layers and depositing the sensor into the trench. The sensor can include a sensor stack sandwiched between first and second electrically conductive lead layers. First and second electrically insulating side walls are formed at either side of the sensor stack. First and second hard bias layers extend from the sides of the sensor stack, being separated from the sensor stack by the first and second electrically insulating side walls. First and second physically hard insulation layers are provided over each of the hard bias layers.

Abstract: A magnetoresistive sensor having a trackwidth defined by AFM biasing layers disposed beneath a free layer of the sensor. The present invention provides a current in plane magnetoresistive sensor that includes a non-magnetic, electrically conductive layer in a trackwidth region. The non-magnetic, electrically conductive layer can be for example Ta, but could be some other material. This non-magnetic, electrically conductive layer has first and second laterally opposed sides and a planar upper surface. First and second insulating layers are formed at each of the sides of the non-magnetic, electrically conductive layer, and bias layers extend laterally outward from the insulation layers. The bias layers can be constructed of either an antiferromagnetic (AFM) material or could be constructed of a hard magnetic material such as CoPtCr. The bias layers have planar upper surfaces that are coplanar with the upper surface of the non-magnetic, electrically conductive layer.

Abstract: A magnetic head in one embodiment includes first and second ferromagnetic shield layers, first and second nonmagnetic read-gap layers positioned between the first and second ferromagnetic shield layers, a sensor used in a current-in-plane (CIP) mode, first and second longitudinal bias layers electrically coupled with the sensor, and first and second conducting layers electrically coupled with the first and second longitudinal bias layers, respectively.

Abstract: A read sensor stabilized by bidirectional anisotropy is disclosed. The read sensor includes a longitudinal flux-closure structure comprising an antiferromagnetic pinning layer, a ferromagnetic bias layer, a nonmagnetic spacer layer, and a ferromagnetic sense layer. In this longitudinal flux-closure structure, the antiferromagnetic pinning layer directly couples to the ferromagnetic bias layer inducing strong unidirectional anisotropy, and also indirectly couples to the ferromagnetic sense layer inducing weak unidirectional anisotropy. In addition, the ferromagnetic bias layer antiparallel-couples to the ferromagnetic sense layer across the nonmagnetic spacer layer inducing optimal bidirectional anisotropy. The magnetization of the ferromagnetic bias layer thus remains rigidly pinned mainly due to the strong unidirectional anisotropy, while the magnetization of the ferromagnetic sense layer can rotate freely and stably due to the optimal bidirectional anisotropy.

Abstract: A method and apparatus providing a stabilized top shield in a read head used for the longitudinal or perpendicular magnetic recording is disclosed. The top shield includes a laminate structure including at least three layers of ferromagnetic and antiferromagnetic films in a frame. Unidirectional anisotropy induced at the interface of the ferromagnetic and antiferromagnetic films is optimized by selecting suitable compositions and thicknesses to achieve the stabilization of the top shield while maintaining high permeability. In an alternative method, the top shield includes a ferromagnetic Ni—Fe film in a central region and multiple layers comprising ferromagnetic Co—Fe and Ni—Fe layers and an antiferromagnetic layer.

Abstract: An in-line lapping guide uses a contiguous resistor in a cavity to separate a lithographically-defined sensor from the in-line lapping guide. As lapping proceeds through the cavity toward the sensor, the resistance across the sensor leads increases to a specific target, thereby indicating proximity to the sensor itself. The contiguous resistor is fabricated electrically in parallel to the sensor and the in-line lapping guide. The total resistance across the sensor leads show resistance change even when lapping through the cavity portion. One method to produce the contiguous resistor is to partial mill the cavity between the sensor and the in-line lapping guide so that a film of metal is left. Total resistance across leads is the parallel resistance of the sensor, the contiguous resistor, and the in-line lapping guide.

Abstract: A tunneling magnetoresistive (TMR) sensor includes a first ferromagnetic (FM) layer (e.g. a sense or reference layer), a barrier layer formed over the first FM layer, and a second FM layer (e.g. a sense or reference layer) formed over the barrier layer. The barrier layer is made of magnesium-oxide (Mg—O). The sense and reference layers of the TMR sensor exhibit controlled magnetic properties, the barrier layer provides a low junction resistance-area product, and the TMR sensor exhibits a high TMR coefficient. The junction resistance is sufficiently low so as to prevent electrostatic discharge (ESD) damage to submicron-sized TMR sensors used for magnetic recording at ultrahigh densities.

Abstract: The GMR read head includes a GMR read sensor and a longitudinal bias (LB) stack in a read region, and the GMR read sensor, the LB stack and a first conductor layer in two overlay regions. In its fabrication process, the GMR read sensor, the LB stack and the first conductor layer are sequentially deposited on a bottom gap layer. A monolayer photoresist is deposited, exposed and developed in order to open a read trench region for the definition of a read width, and RIE is then applied to remove the first conductor layer in the read trench region. After liftoff of the monolayer photoresist, bilayer photoresists are deposited, exposed and developed in order to mask the read and overlay regions, and a second conductor layer is deposited in two unmasked side regions. As a result, side reading is eliminated and a read width is sharply defined by RIE.

Abstract: The GMR read head includes a GMR read sensor and a longitudinal bias (LB) stack in a read region, and the GMR read sensor, the LB stack and a first conductor layer in two overlay regions. In its fabrication process, the GMR read sensor, the LB stack and the first conductor layer are sequentially deposited on a bottom gap layer. A monolayer photoresist is deposited, exposed and developed in order to open a read trench region for the definition of a read width, and RIE is then applied to remove the first conductor layer in the read trench region. After liftoff of the monolayer photoresist, bilayer photoresists are deposited, exposed and developed in order to mask the read and overlay regions, and a second conductor layer is deposited in two unmasked side regions. As a result, side reading is eliminated and a read width is sharply defined by RIE.

Abstract: A Current-Perpendicular-to-Plane (CPP) Giant Magneto-Resistance (GMR) sensor (700/800) has either a composite film (708) embedded into a ferromagnetic reference layer (710) or a composite film (806) embedded into a ferromagnetic keeper layer (804). The embedded composite film is deposited by sputtering from a ferromagnetic metallic target and a non-magnetic oxide target simultaneously or sequentially. Varying sputtering powers of the ferromagnetic metallic and non-magnetic oxide targets leads to various volume fractions of ferromagnetic metallic and non-magnetic oxide phases. By carefully adjusting these volume fractions, the product of junction resistance and area of the CPP GMR sensor (700/800) can be finely tuned to a designed value and thus provide optimum read performance of the CPP GMR sensor (700/800) for magnetic recording at ultrahigh densities.

Abstract: A method is disclosed for fabricating a read sensor for a magnetic head for a hard disk drive having a read sensor stack and two lateral stacks. The method of fabrication includes forming lateral stacks on a gap layer, surrounding a groove to form a template. The read sensor stack is then formed in the groove, which defines the lateral dimensions of the read sensor stack, and lead layers are then formed on the lateral stacks. Also disclosed is a read head for a disk drive having a sensor stack defined by pre-established lateral stacks, and a disk drive having the read head.

Abstract: A giant magnetoresistance (GMR) magnetic head that includes a GMR read sensor with a stitched longitudinal bias (LB) stack. The GMR read sensor includes seed, pinning, pinned, spacer, sense and cap layers in a read region, and its seed and pinning layers are extended into two side regions. The LB stack is fabricated on the pinning layer in the two side regions and includes separation, seed and LB layers. The separation layer, preferably made of an amorphous film, separates the pinning layer from the seed and LB layers and thereby prevents unwanted crystalline effects of the pinning layer. Monolayer photoresist patterning and chemical mechanical polishing may be incorporated into the fabrication process of the GMR head to attain uniform thicknesses of the separation, seed and LB layers, and to align the midplane of the LB layer at the same horizontal level as the midplane of the sense layer.

Abstract: A giant magnetoresistance (GMR) sensor with side longitudinal bias (LB) stacks is proposed for magnetic recording at ultrahigh densities. The GMR sensor extends from a read region into two side regions. The side LB stacks overlies the GMR sensor in the two side regions, rigidly pinning sense layers through antiparallel coupling across an antiparallel coupling spacer layer. Magnetostatic interactions occur in the sense layers between the read and side regions, thereby stabilizing the sense layers in the read region.

Abstract: A dual spin valve (SV) sensor is provided with a longitudinal bias stack sandwiched between a first SV stack and a second SV stack. The longitudinal bias stack comprises an antiferromagnetic (AFM) layer sandwiched between first and second ferromagnetic layers. The first and second SV stacks comprise antiparallel (AP)-pinned layers pinned by AFM layers made of an AFM material having a higher blocking temperature than the AFM material of the bias stack allowing the AP-pinned layers to be pinned in a transverse direction and the bias stack to be pinned in a longitudinal direction. The demagnetizing fields of the two AP-pinned layers cancel each other and the bias stack provides flux closures for the sense layers of the first and second SV stacks.