Abstract: A magnetoresistive read 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 nonmagnetic metallic layer. A layer of nonmagnetic electrically conductive material is deposited adjacent to and in contact with one of the ferromagnetic layers, referred to as a filter layers to form a back or conduction layer which provides a low resistance path for conduction electrons transmitted through the adjacent filter layer. The thickness of the filter layer is selected such that it effectively blocks conduction electrons having spins antiparallel to the direction of magnetization in the filter layer while allowing conduction electrons with parallel spins to be transmitted through the layer into the adjacent back layer.

Abstract: Controlled current pulses applied to a shaped resistive heating element formed on the bonding surface of a base or substrate component provide sufficient heat to the bonding interface formed between a chip and the base bonding surface to produce a high bonding temperature at the bonding interface while maintaining an opposite surface of the chip at or below a relatively low temperature critical for components formed or mounted on the chip surface. A layer of a thermally setting thin-film bonding agent is applied over a serpentine-shaped resistive heating element having a relatively narrow linewidth formed on the base component bonding surface. The chip to be bonded is retained in a desired position against the bonding surface over the heating element and bonding agent layer while a current pulse is applied to the heating element via contact pads.

Abstract: An object-oriented, hierarchical model of a computer network layered communications subsystem is implemented in a configuration database subsystem to create and maintain a configuration database and to provide configuration data to the layered communications subsystem. The layered communications subsystem is represented by a set of defined object classes, each object class corresponding to one or more functions defined at each of the communications subsystem layers, the object classes being related in a hierarchical relationship which preserves the functional relationship among the various functions in the various layers making up the layered communications subsystem.

Abstract: A method for fabricating a thin-film magnetic read/write head that eliminates contrast effects producing notching in a thin-film magnetic head coil caused by subsurface reflectivity at a reflective layer step during a photolithography step in the fabrication of the coil is provided. The method comprises the steps of forming a first permalloy yoke on a substrate, wherein the edges of the first yoke create steps from the top of the first yoke down to the substrate, forming a partial conformal layer of an electric insulation material over the first permalloy yoke and the substrate, forming a conformal copper seed layer over the electric insulation layer, forming a conductive coil on the electric insulation layer, wherein the copper coil is fabricated using a lithography process including placing a phase-shifting mask, formed in the image of the coil and containing non-printable openings covered by transparent material of a thickness that creates a 180.degree.

Abstract: An integral combination magnetic transducer and suspension assembly suitable for use in both contact recording and in winchester-type applications is described. A generally rectangular elongated flat suspension member includes a vertical-type inductive read/write transducer formed integrally with the suspension member and is embedded in one end of the suspension member. The vertical inductive transducer is suitable for vertical recording applications. The transducer vertical magnetic pole tip and magnetic yoke structure are formed at one end of the suspension member with the vertical pole tip extending to and exposed at a air bearing surface formed on the lower surface of a slider-shaped protrusion extending from the lower surface of the end of the suspension member. The integral transducer/suspension assembly can be adapted for either flying above the recording media or for use in continuous contact with the recording media. The air bearing surface is formed on the lower surface of a wear pad.

Abstract: A method and apparatus for editing the displayed voice wave form by marking the portion of interest on the screen is disclosed. Marked segment may then be deleted, for example, or copied into another segment in second voice editing window. In either case, pointers are established at the selected marker positions of the displayed voice segment and in the corresponding positions of uncompressed voice segments. The voice data is treated as a stream of fixed-length micro-segments, where there is a predictable correlation between the positions of the compressed and uncompressed data. In the implementation at hand, these micro-segments are 20 ms. in length. Editing is accomplished by modifying micro-segments in both the compressed and uncompressed segments simultaneously. When the user is satisfied with the result, the edited wave form is redrawn on the screen. The user may then SAVE the result, and the entire segment is rewritten to the data base, replacing the previous version.

Abstract: An optical recording system in which the optical head is operated in physical contact with the surface of the optical recording medium during system operation at a selected operating speed. The optical head includes one or more optical elements mounted on a substrate which is in physical, sliding contact with the recording medium. The substrate is fabricated from a crystalline material which has a non-linear load versus friction characteristic in the negative load region. When the head is in sliding contact with the recording medium surface, a restoring force is generated which maintains the optical head in physical contact with the recording medium overcoming any lifting forces generated by the moving air layer adjacent the recording medium surface. This allows the head to be operated with a negative external load applied.

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: A magnetoresistive (MR) sensor comprising a layered structure having at least one trilayer comprising a first and a second thin film ferromagnetic layers separated by and in interfacial contact with a third thin film non-metallic layer. A fourth thin film layer of material is within the first ferromagnetic layer, and the fourth layer has a thickness between a fraction of a monolayer and several monolayer and is located at predetermined distance from the interface between the first and third layers. A current flow is produced through the MR sensor and variations in resistivity of the MR sensor produced by rotation of the magnetization in one or both of the ferromagnetic layers is sensed as a function of the magnetic field being sensed.

Abstract: A multilayer magnetoresistive (MR) sensor formed on a substrate includes alternating layers of a ferromagnetic material and a non-magnetic metallic material. The ferromagnetic material and the non-magnetic material form bilayers which exhibit the property that the magnetoresistance of the multilayered structure oscillates as a function of thickness of the non-magnetic material. A current flow is produced through the MR sensor, and the variations in the resistivity of the MR sensor are sensed as a function of the magnetic field being sensed.

Abstract: In digital data transmission and storage, binary data strings are encoded into symbols from a quaternary alphabet by a specific inventive use of finite-state machines. The novel, high-rate quaternary codes offer spectral shaping properties together with a significant increase in noise margin when used on channels which lend themselves to partial-response shaping. In principle, the encoding occurs in three steps: a u-state transition diagram generates quaternary symbols whose running digital sum assumes values from a given set; the u-state transition diagram is converted into a v-state machine, each of the v states being associated with a number of transitions sufficient to encode the input data bytes into output code words; finally, the v-state machine is switched into a next state depending on its current state and the last encoded input data byte.

Abstract: A method is disclosed for adapting, in a self-training procedure, an equalizer based on distributed-arithmetic design. In such an equalizer, in each modulation interval addresses are derived from stored received signal samples x.sub.n.sup.q to choose some of the values stored in a look-up table. The chosen table values are combined by shift-and-add operations to obtain an equalizer output value y.sub.n. According to the novel adaptation scheme, only one of the chosen look-up table values is selected per modulation interval, for updating it in a particular fashion to reduce the error detected. The disclosed scheme ensures uniform selection of the stored look-up table values for updating. Only one additional shift-and-add operation is required per modulation interval to achieve satisfactory adaptation of the equalizer. No training sequence is required to be transmitted, and the scheme converges in all situations.

Abstract: A magnetoresistive (MR) sensor comprising a sputtered layer of ferromagnetic material and a sputtered layer of antiferromagnetic nickel-manganese (Ni-Mn) to provide an exchange coupled longitudinal bias field in the MR element is described. The antiferromagnetic layer overlays the MR layer and may be patterned to provide the longitudinal bias field only in the end regions of the MR layer. Alternatively, the antiferromagnetic layer can underlay the MR layer with a Zr underlayer to enhance the exchange-coupled field. As initially deposited, the Ni-Mn layer is face-centered-cubic and exhibits little or no exchange-coupled field. After one annealing cycle at a relatively low temperature, the Ni-Mn layer is face-centered-tetragonal and exhibits increased crystallographic ordering and provides sufficient exchange coupling for the MR element to operate. Addition of chromium to the Ni-Mn alloy provides increased corrosion resistance.

Abstract: A contact magnetic storage system in which the slider, which supports the magnetic read/write head, is in physical contact with a rigid magnetic storage medium during system operation at a selected operating speed. The slider material has a load versus friction characteristic that is non-linear in the negative load region. This characteristic allows the slider to be suspended from an access arm with zero or negative external loading. In a conventional magnetic storage system, at operating speed the slider is lifted away from the surface of the storage medium by at least the thickness of the air film adjacent the moving storage medium surface. In the present invention, due to the non-linear load versus friction characteristics of the slider material, a restoring force is generated at system operating speed which overcomes the lift of the air bearing and maintains the slider in contact with the storage medium surface without substantial wear or damage to either the slider or the storage medium.

Abstract: A magnetoresistive read 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..

Abstract: A magnetoresistive read sensor based on the spin valve effect and having a multilayered, dual spin valve structure is described. The sensor read element includes first, second and third layers of ferromagnetic material separated from each other by layers of non-magnetic metallic material. The first and third layers of ferromagnetic material, i.e., the outer layers of the structure, have their magnetization orientation fixed, while the second, intermediate ferromagnetic layer is magnetically soft and has its magnetization oriented perpendicular to that of both the outer ferromagnetic layers in the absence of an applied magnetic field. In one preferred embodiment, the two outer ferromagnetic layers have their magnetizations fixed parallel to each other by exchange coupling with adjacent antiferromagnetic layers.

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 thin film magnetic head comprises a first magnetic yoke layer extending from a back gap region to a sensing edge such as an air bearing surface (ABS), and a second magnetic yoke layer contacting the first magnetic yoke layer at the back gap region and extending to the ABS in a position aligned with, but spaced from, the first magnetic yoke layer. A pole tip structure, with geometry formed by a single photolithographic process, comprising a first pole tip layer, a gap forming layer, and a second pole tip layer is positioned between the first and second magnetic yoke layers at the ABS with the first pole tip layer in contact with the first magnetic yoke layer and the second pole tip layer in contact with the second magnetic yoke layer at the ABS.

Abstract: A method for making a magnetic head slider having a protective coating on the rails thereof, the protective coating containing a thin adhesion layer, a thin layer of amorphous hydrogenated carbon, and a thin masking layer. The protective coating is deposited on the air bearing surface of the slider after the thin film magnetic heads are lapped to a chosen dimension, but before the pattern of rails is produced on the air bearing surface. The protective coating protects the magnetic head during the rail fabrication process and in usage in a magnetic recording system protects the magnetic head from wear and corrosion damage.