Abstract: A method to measure a magnetic field is provided. The method includes applying an alternating drive current to a drive strap overlaying a magnetoresistive sensor to shift an operating point of the magnetoresistive sensor to a low noise region. An alternating magnetic drive field is generated in the magnetoresistive sensor by the alternating drive current. When the magnetic field to be measured is superimposed on the alternating magnetic drive field in the magnetoresistive sensor, the method further comprises extracting a second harmonic component of an output of the magnetoresistive sensor. The magnetic field to be measured is proportional to a signed amplitude of the extracted second harmonic component.

Abstract: A method and system provide a magnetoresistive structure from a magnetoresistive stack that includes a plurality of layers. The method and system include providing a mask that exposes a portion of the magnetoresistive stack. The mask has at least one side, a top, and a base at least as wide as the top. The method and system also include removing the portion of the magnetoresistive stack to define the magnetoresistive structure. The method and system further include providing an insulating layer. A portion of the insulating layer resides on the at least one side of the mask. The method and system further include removing the portion of the insulating layer on the at least one side of the mask and removing the mask.

Abstract: A laminated high moment film with a non-AFC configuration is disclosed that can serve as a seed layer for a main pole layer or as the main pole layer itself in a PMR writer. The laminated film includes a plurality of (B/M) stacks where B is an alignment layer and M is a high moment layer. Adjacent (B/M) stacks are separated by an amorphous layer that breaks the magnetic coupling between adjacent high moment layers and reduces remanence in a hard axis direction while maintaining a high magnetic moment and achieving low values for Hch, Hce, and Hk. The amorphous material layer may be made of an oxide, nitride, or oxynitride of one or more of Hf, Zr, Ta, Al, Mg, Zn, Ti, Cr, Nb, or Si, or may be Hf, Zr, Ta, Nb, CoFeB, CoB, FeB, or CoZrNb. Alignment layers are FCC soft ferromagnetic materials or non-magnetic FCC materials.

Abstract: A method is provided for fabricating a read element with leads that overlay a top surface of a sensor of the read element. The method includes forming a mask over a sensor layer, then using the mask to define the sensor from the sensor layer. The mask is then narrowed and a lead layer is formed that overlays both ends of the top surface of the sensor without covering a center portion of the top surface.

Abstract: A magnetic sensor, formed from a pair of magnetically free layers located on opposing sides of a non-magnetic layer, and method for its manufacture, are described. Biasing these free layers to be roughly orthogonal to one another causes them to be magnetostatically coupled in a weak antiferromagnetic mode. This enables the low frequency noise spectra of the two free layers to cancel one another. Careful control of the SH/TW ratio is an important feature of the device.

Abstract: A method is disclosed for fabricating a read head for a magnetic disk drive having a read head sensor and a hard bias layer, where the read head has a shaped junction between the read head sensor and the hard bias layer. The method includes providing a layered wafer stack to be shaped. A single- or multi-layered photoresist mask having no undercut is deposited upon the layered wafer stack to be shaped. The layered wafer stack is shaped by the output of a milling source, where the shaping includes partial milling to within a partial milling range to form a shaped junction. A hard bias layer is then deposited which is in contact with the shaped junction of the wafer stack.

Abstract: A fabrication method for thin film magnetic heads, comprises, forming a Current Perpendicular to a Plane (CPP) sensor film over a lower shield and a first chemical mechanical polishing (CMP) stop film over the CPP sensor film, etching the CPP sensor film and forming a track width on the CPP sensor film, and covering at least the etching section of the CPP sensor film with an insulating film. The method further comprises forming a CMP dummy film over the insulating film and a second CMP stop film over the CMP dummy film, exposing the first CMP stop film, and removing the first CMP stop film and the second CMP stop film by oxygen reactive ion etching (RIE) and the CMP dummy film by fluorine RIE, and forming an upper shield film over the insulating film and over the CPP sensor film.

Abstract: A giant magnetoresistive (GMR) head is formed to include a recess in an overcoat layer that reduces stress on the poles. The process includes depositing a seed layer over the overcoat layer prior to plating a metal mask layer with an opening where the recess is to be formed, wet chemical etching the seed layer through the opening in the mask layer and performing an ion milling process to remove any remaining traces of the seed layer. With the seed layer completely removed, a trench having smooth sidewalls and bottom is etched in the overcast layer by a reactive ion etch (RIE) process. The saw that is used to separate the head elements in the wafer can be passed through the clean trench without contacting the overcoat layer, thereby avoiding the chipping and cracking that might otherwise result from the use of a silicon dioxide or silicon nitride overcoat layer.

Abstract: An embodiment of the invention is a magnetic head with overlaid lead pads that contact the top surface of the sensor between the hardbias structures and do not contact the hardbias structures which are electrically insulated from direct contact with the sensor. The lead pad contact area on the top of the sensor is defined by sidewall deposition of a conductive material to form leads pads on a photoresist prior to formation of the remainder of the leads. The conductive material for the lead pads is deposited at a shallow angle to maximize the sidewall deposition on the photoresist, then ion-milled at a high angle to remove the conductive material from the field while leaving the sidewall material. An insulation layer is deposited on the lead material at a high angle, then milled at a shallow angle to remove insulation from the sidewall.

Abstract: In a magnetic sensor, a lower terminal layer, a magnetosensitive layer, and a cover film are simultaneously patterned into substantially the same size. The opposing surface of the lower terminal layer, which opposes the magnetosensitive film is substantially superposed on one opposing surface of the magnetosensitive film. The opposing surface of the upper terminal layer, which opposes the magnetosensitive film is formed into a shape smaller than and included in the other opposing surface of the magnetosensitive film. This implements a magnetic sensor which uses a CPP structure and is yet readily processible and which includes a substantially accurate fine CPP structure in accordance with a desired output.

Abstract: In a magnetoresistive effect element using a ferromagnetic tunnel junction having a tunnel barrier layer sandwiched between at least a pair of ferromagnetic layers, a magnetization free layer comprising one of the ferromagnetic layers is composed of a single layer of a material having an amorphous or microcrystal structure or a material layer the main portion of which has an amorphous or microcrystal structure. The magnetoresistive effect element can produce excellent magnetic-resistance characteristics, and a magnetic memory element and a magnetic memory device using the magnetoresistive effect element as a memory element thereof can improve both of write and read characteristics at the same time.

Abstract: A magnetic head having a spin valve sensor that is fabricated utilizing an Al2O3, NiMn0, Si seed layer upon which a PtMn spin valve sensor layer structure is subsequently fabricated. In the preferred embodiment, the Si layer has a thickness of approximately 20 ? and the PtMn layer has a thickness of approximately 120 ?. An alternative fabrication process of the Si layer includes the overdeposition of the layer to a first thickness of from 15 ? to 45 ? followed by the etching back of the seed layer of approximately 5 ? to approximately 15 ? to its desired final thickness of approximately 20 ?. The Si layer results in an improved crystal structure to the subsequently fabricated PtMn and other spin valve sensor layers, such that the fabricated spin valve is thinner and exhibits increased ?R/R and reduced coercivity.

Abstract: A thin film head comprising a GMR element formed of an antiferromagnetic layer, a pinning layer, a nonmagnetic conductive layer and a free magnetic layer; and a pair of the right and the left laminated longitudinal biasing layers, each of the layers containing a hard magnetic layer, a nonmagnetic layer and a soft magnetic layer provided on said free magnetic layer of GMR element. Said hard magnetic layer and said soft magnetic layer are antiferromagnetically exchange-coupled via said nonmagnetic layer, and said hard magnetic layer and said free magnetic layer locating next to said hard magnetic layer are ferromagnetically coupled. The present invention contains also a method for manufacturing the thin film head.

Abstract: A magnetoresistive thin film head comprises a magnetoresistive element including an antiferromagnetic layer, a pinned layer, a nonmagnetic conductive layer and a free magnetic layer, and a pair of the right and the left laminated transverse biasing layers, each including a nonmagnetic layer, a ferromagnetic layer and an antiferromagnetic layer, provided on the free magnetic layer constituting said magnetoresistive element. The layer thickness of said nonmagnetic layer has been established to a certain specific value so that magnetizing direction in said free magnetic layer opposing to the ferromagnetic layer via said nonmagnetic layer assumes a direction that is opposite to that of said ferromagnetic layer.

Abstract: A magnetoresistive sensor for use in a data storage device has a recessed sensing element (magnetic tunnel junction, CPP spin valve, etc.) with an exchange biased sensing ferromagnetic (free) layer, and a flux guide that magnetically connects the sensing element to a sensing surface of the sensor. The free layer is selectively exchange biased by a layer of exchange bias material placed under non-active regions of the free layer that lie outside the sensing element and flux guide track widths. The flux guide is provided by extending the free layer from a forward edge of the sensing element to the sensor surface. Advantageously, the sensing element and the flux guide have equal track width so that magnetic flux directed from the flux guide into the sensing element is not diluted with consequent loss of sensitivity.

Abstract: An antiferromagnetic stabilization scheme is employed in a magnetic head for magnetically stabilizing a free layer of a spin valve. This is accomplished by utilizing an antiferromagnetic oxide film below a spin valve sensor in a read region and first and second lead layers in end regions and a ferromagnetic film in each of the lead layers that exchange couples to the antiferromagnetic oxide film in the end regions. The ferromagnetic films are pinned with their magnetic moments oriented parallel to an air bearing surface (ABS) of the magnetic head. The ferromagnetic film magnetostatically couples to the free layer which causes the free layer to be in a single magnetic domain state. Accordingly, when the free layer is subjected to magnetic incursions from a rotating disk in a disk drive, the free layer maintains a stable magnetic condition so that resistance changes of the free layer are not altered by differing magnetic conditions of the free layer.

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 antiferromagnetic stabilization scheme is employed in a magnetic head for magnetically stabilizing a free layer of a spin valve. This is accomplished by utilizing an antiferromagnetic oxide film below a spin valve sensor in a read region and first and second lead layers in end regions and a ferromagnetic film in each of the lead layers that exchange couples to the antiferromagnetic oxide film in the end regions. The ferromagnetic films are pinned with their magnetic moments oriented parallel to an air bearing surface (ABS) of the magnetic head. The ferromagnetic films magnetostatically couple to the free layer which causes the free layer to be in a single magnetic domain state. Accordingly, when the free layer is subjected to magnetic incursions from a rotating disk in a disk drive, the free layer maintains a stable magnetic condition so that resistance changes of the free layer are not altered by differing magnetic conditions of the free layer.

Abstract: A TMR element includes: a free layer formed on a lower gap layer; a tunnel barrier layer formed on the free layer; and a pinned layer formed on the tunnel barrier layer. The pinned layer and the tunnel barrier layer have sidewalls formed through etching. The TMR element further comprises a deposition layer made of a material that is separated by etching and deposits on the sidewalls and undergoes oxidation.

Abstract: Ultrafast solid state amplifiers of electrical current, including power amplification devices, use injection of spin-polarized electrons from a magnetic region into another magnetic region through a semiconductor control region and electron spin precession inside the control region induced by a magnetic field resulting from a current flowing through a conductive nanowire. The amplifiers may include magnet-semiconductor-magnet heterostructures and are able to operate on electric currents and electromagnetic waves having frequencies up to 100 GHz or more.

Abstract: A method for maximizing the interfacial properties of magnetoresistive sensors, such as spin valve and GMR sensors used in storage devices, comprises selecting the materials for ferromagnetic layers and for electrically conductive spacers that are interposed between the ferromagnetic layers. The electronegativities of the selected materials are substantially matched so that an absolute value of the differences in electronegativities is minimized. The conductive spacer material provides a relatively low resistivity and a large mean free path. The sensors experience greater chemical and thermal stability, are corrosion resistant, and realize an increased signal output.

Abstract: A bilayer mask employed for lift off has a top strip which bridges between first and second bilayer portions and is completely undercut so that when one or more materials is sputter deposited the materials do not form fences abutting recessed edges of a bottom layer in undercuts below a top layer. Sacrificial protective layers are formed on a sensor and lead layers for protecting these components while overlapping portions of these materials on the top of the sensor formed during deposition can be removed by ion beam sputtering, after which the sacrificial protective layers can be removed by ion milling or reactive ion etching.

Abstract: A method of making a dual spin valve sensor includes the steps of forming first and second pinned layer structures, forming antiferromagnetic first and second pinning layers exchange coupled to the first and second pinned layer structures, forming an antiparallel (AP) coupled free layer structure between the first and second pinned layer structures, forming nonmagnetic conductive first and second spacer layers between the AP coupled free layer structure and the first and second pinned layer structures respectively, and a making of the AP coupled free layer structure includes the steps of forming ferromagnetic first, second and third antiparallel (AP) coupled free layers and forming a first antiparallel coupling layer between the first and second AP coupled free layers and a second antiparallel coupling layer between the second and third AP coupled free layers.

Abstract: A spin valve sensor has a pinned layer structure that has a net positive stress induced uniaxial anisotropy that promotes a pinning of the pinned layer structure in a pinned direction for stabilizing the pinning of the pinned layer structure at high temperatures near to a blocking temperature of a pinning layer which is exchange coupled to the pinned layer.

Abstract: A method and system for detecting a magnetic field utilizing a magnetoresistor of a magnetic sensor is disclosed. A normalized magnetoresistance associated with the magnetoresistor can be calculated such that the magnetoresistor comprises an initial magnetization direction thereof. The magnetic field is generally permitted to exceed an ability of the magnetoresistor to remain pointed in the initial magnetization direction, thereby enabling the magnetoresistor to experience a magnetization reversal thereof. The normalized resistance can be placed into a new state in response to the magnetization reversal thereof, thereby permitting the normalized resistance to be utilized as a switch thereof and allowing the magnetic sensor to detect changes in the magnetic field associated with the magnetoresistor.

Abstract: A dual active element magnetoresistive tape read head uses weak biasing of active layers to reduce Barkhausen noise. The read head includes a first insulator layer. A first active magnetoresistive layer is built on the first insulator layer. A second insulator layer is built on the first active magnetoresistive layer. A second active magnetoresistive layer is on the second insulator layer. The second active magnetoresistive layer is magnetostatically coupled to the first active magnetoresistive layer. A third insulator layer is on the second active magnetoresistive layer. At least one insulator layer is a biasing layer comprised of an electrically nonconductive antiferromagnetic material.

Abstract: A free layer for a spin valve sensor includes a cobalt iron (CoFe) film which has an easy axis oriented perpendicular to an air bearing surface (ABS) of a read head and a nickel iron (NiFe) film which has an easy axis oriented parallel to the ABS and parallel to the major planes of the thin film layers. In a further embodiment the free layer is annealed at a high temperature in the presence of a field which is oriented perpendicular to the ABS.

Abstract: A spin valve sensor in a read head has a spacer layer which is located between a self-pinned AP pinned layer structure and a free layer structure. The free layer structure is longitudinally stabilized by first and second hard bias layers which abut first and second side surfaces of the spin valve sensor. The AP pinned layer structure has an antiparallel coupling layer (APC) which is located between first and second AP pinned layers (AP1) and (AP2). The invention employs a preferential setting of the magnetic moments of the AP pinned layers by applying a field at an acute angle to the head surface in a plane parallel to the major planes of the layers of the sensor. The preferential setting sets a proper polarity of each AP pinned layer, which polarity conforms to processing circuitry employed with the spin valve sensor.

Abstract: A method for forming an anisotropic magnetoresistive (MR) sensor element, and the anisotropic magnetoresistive (MR) sensor element formed in accord with the method. In accord with the method, there is first provided a substrate. There is then formed over the substrate a seed layer formed of a magnetoresistive (MR) resistivity sensitivity enhancing material selected from the group consisting or nickel-chromium alloys and nickel-iron-chromium alloys. There is then formed over the seed layer a nickel oxide material layer. Finally, there is then formed over the nickel oxide material layer a magnetoresistive (MR) layer. The method contemplates the anisotropic magnetoresistive (MR) sensor element formed in accord with the method. The nickel oxide material layer provides the anisotropic magnetoresistive (MR) sensor element with an enhanced magnetoresistive (MR) resistivity sensitivity.

Abstract: An object of the invention is to minimize the difference in reproducing output of a magnetoresistive device for a reproducing head. An MR device which composes a reproducing head is formed as a laminated structure in which a SAL film, an insulating film and an MR film which is a magnetoresistive film are laminated. The side-end faces of the MR film slope toward the supporting surface of a base body and the side-end faces of the SAL film are formed substantially vertical to the supporting surface of the base body. An insulating film, which is provided in the related art, is not provided on the side-end faces of the MR film and the SAL film so as to make them directly in contact with a first electrode layer. The area of the side-end faces of the SAL film is sufficiently smaller than that of the MR film, and the ratio of both areas can be set to a constant value.

Abstract: A dual active element magnetoresistive tape read head uses weak biasing of active layers to reduce Barkhausen noise. The read head includes a first insulator layer. A first active magnetoresistive layer is built on the first insulator layer. A second insulator layer is built on the first active magnetoresistive layer. A second active magnetoresistive layer is on the second insulator layer. The second active magnetoresistive layer is magnetostatically coupled to the first active magnetoresistive layer. A third insulator layer is on the second active magnetoresistive layer. At least one insulator layer is a biasing layer comprised of an electrically nonconductive antiferromagnetic material.

Abstract: A dual active element magnetoresistive tape read head uses weak biasing of active layers to reduce Barkhausen noise. The read head includes a first insulator layer. A first active magnetoresistive layer is built on the first insulator layer. A second insulator layer is built on the first active magnetoresistive layer. A second active magnetoresistive layer is on the second insulator layer. The second active magnetoresistive layer is magnetostatically coupled to the first active magnetoresistive layer. A third insulator layer is on the second active magnetoresistive layer. At least one insulator layer is a biasing layer comprised of an electrically nonconductive antiferromagnetic material.

Abstract: A magnetoresistive sensor has a read gap that is made of a slow ion milling rate material. The slow milling rate read gap allows a blunt end to be formed for the sensor without excessive overmilling into the read gap. The read gap may also be formed of plural layers with at least one of the layers having a low milling rate. This allows the other read gap layer to have complimentary attributes, such as high thermal conductivity, low stress, less pinholes and/or better dielectric properties. The electromagnetic characteristics of MR sensors having such steeply sloped ends are enhanced both in reading signals and reducing noise. The track width of such a sensor can be more accurately formed due to the blunt shape of the contiguous junction, quantizing signals and reducing errors from reading adjacent tracks. The sensor can also be made to have a sharper linear bit resolution, due to a thinner, high-integrity read gap.