Abstract: The present invention may be regarded as a self-servo writing disk drive comprising a head having a read element radially offset from a write element. During a first time interval, the read element is positioned over a first radial location to read first A clock data to generate first circumferential timing information and first A servo bursts to generate first position control information. The first position control information is used for positioning the write element over a second radial location, and the first circumferential timing information is used for writing second B clock data and second B servo bursts to the second radial location. During a second time interval, the read element is positioned over the first radial location to read first B clock data to generate second circumferential timing information and first B servo bursts to generate second position control information.

Abstract: A magnetic disk storage system with high linear resolution magnetoresistive (MR) head or heads comprising a dielectric substrate, a first magnetic shield, a first gap insulation layer, an MR stripe element, conductive leads, a second gap insulation layer, and a second magnetic shield. Back-fill layers of insulation material are deposited on the first gap insulation layer adjacent the MR element and/or on the second gap insulation layer in thicknesses substantially sufficient to at least in part replace insulation material removed during the various processing steps to ensure against short circuiting of the MR element.

Abstract: In a bi-layer lift-off process, the adhesion characteristics of a PMGI release layer are substantially improved by the use of ortho-hydroxy substituted 4-phenylazo compounds (azo dyes), a class of nonactinic dyes, as an adhesion promoter additive. These azo dyes, due to their chemical structure, exhibit selective binding to various metals by acting as a chelating ligand to the metal surface. Formulations of a specific azo dye, Sudan Orange G, at concentrations from 0.25 to 1.0 percent (by weight) in PMGI exhibits no loss of adhesion at prebake temperature in the range of 120 to 160 degrees C.

Abstract: A method of lapping magnetoresistive (MR) heads individually which provides an MR element having a desired height with minimized skew is described. During fabrication of the MR head, one or more shunt resistors are formed between the edge of the MR element and the head air bearing surface. The shunt resistors are electrically connected at each end to extensions of the MR electrical leads and connected to the MR element and to each other at points between the ends forming a resistor network. During lapping of the MR head, the resistance of the resistor network is measured by an Ohmmeter connected between the MR element leads. As portions of the shunt resistors are ground away, the changes in the measured resistance of the resistor network are used to monitor and control any skew in the lapping process.

Abstract: An MR read transducer is provided which has a central region located between a pair of end regions. The central region and the pair of end regions extend along a width of the MR read transducer. An MR layer extends along the width of the MR read transducer and has an active layer portion located between a pair of passive layer portions, the active layer portion being located in the central region and each passive layer portion being located in a respective end region. A layer is located in the central region and magnetostatically coupled to the active layer portion of the MR layer for transversely biasing the MR layer. Each passive layer portion of the MR layer is permeable so that it is responsive to externally applied magnetic fields.

Abstract: In a bi-layer lift-off process, the adhesion characteristics of a PMGI release layer are substantially improved by the use of ortho-hydroxy substituted 4-phenylazo compounds (azo dyes), a class of nonactinic dyes, as an adhesion promoter additive. These azo dyes, due to their chemical structure, exhibit selective binding to various metals by acting as a chelating ligand to the metal surface. Formulations of a specific azo dye, Sudan Orange G, at concentrations from 0.25 to 1.0 percent (by weight) in PMGI exhibits no loss of adhesion at prebake temperatures in the range of 120 to 160 degrees C.

Abstract: A magnetoresistive sensor includes a magnetoresistive material, formed on a substrate, and having a first edge and a second edge. A first multilayered conductive lead structure is electrically connected to the first edge, and a second multilayered conductive lead structure is electrically connected to the second edge. The first and second conductive lead structures are constructed of multiple layers of thin film materials that alternate between at least one layer of a thin film of a refractory metal interlaid between at least two thin film layers of a highly conductive metal.

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: The present invention includes a plurality of thin film magnetic heads which are arranged in a linear array with a spacing D between adjacent heads. The pole pieces of the magnetic heads are positioned in a side by side relationship in contrast to the normal pancake type of magnetic head. The linear array is angled at a skew angle .theta. with respect to the direction of travel of the magnetic medium. The track pitch is then D sin .theta.. The track width is substantially equal to the thickness of the pole tips P1T and P2T of the magnetic heads. This thickness can be in the order of 3 .mu.m. With such a pole tip thickness the track pitch of each magnetic head in the linear array can be 3-4 .mu.m. A plurality of narrow data tracks can then be provided with minimum pitch by a corresponding number of magnetic heads. The write signals are simultaneously fed to the heads or the read signals are simultaneously fed to the heads. This allows high data rates to be processed.

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: An improved method of manufacturing is provided for making an improved merged MR head. The method employs a photoresist mask with appropriately-sized openings for simultaneously etching numerous vias to various depths over a set time period. After formation of the vias, a single photoresist mask is employed to pattern in one step gap layers G3, G2, G1 and a first shield layer S1 to the desired lateral configuration for the merged MR head. Subsequent to patterning these thin film layers, double insulation layers I2 and I3 are individually soft baked on top of the coil structure of the head followed by patterning of the layers I2/I3 by a single photoresist mask. These layers are then hard baked to retain the desired smooth configuration of the layers. The improved merged MR head has a smooth configuration to its top pole piece P2 because of the smooth configuration of the I2/I3 layer so that flux leakage and saturation problems are minimized.

Abstract: A thin film inductive head having staggered pole-tips with a self-aligned recording gap region. The recording gap region is bounded by stepped pole-tip element with the steps made large with respect to the gap thickness. The pole-tip layers extend back from the air bearing surface to form a throat region that is also large with respect to the gap thickness. The self-aligned staggered pole-tip geometry is suitable for submicron track widths because the pole-tips may themselves be much wider and the self-aligned configuration avoids submicron masking and registration difficulties. The stepped pole-tip surfaces also eliminate the side-writing problem known in the art for overlapping thin film poles.

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 magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed which extends over substantially only the central active region and in which a hard magnetic layer is formed in each end region. The hard magnetic layers form an abutting junction having electrical and magnetic continuity with the MR layer to produce a longitudinal bias in the MR sensor. The transducer is produced by a method in which the same stencil defines the extent of both the MR layer and the hard magnetic layers so that the abutting junctions are formed easily and reliably.

Abstract: A magnetoresistive (MR) sensor is center tapped to provide the difference signals for servo operation on data and sum signals for the data information. The center-tap of the MR sensor is made of a high resistivity material compared to the resistivity of the MR element itself such as tantalum, Nichrome and carbon. Processes which can be used to produce the high resistivity center-tap conductor include an insulator layer to define both the track width and the center-tap conductor and a sequence which first patterns the MR sensor and then masks to define the conductor regions.

Abstract: A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed which extends over substantially only the central active region and in which a hard magnetic layer is formed in each end region. The hard magnetic layers form an abutting junction having electrical and magnetic continuity with the MR layer to produce a longitudinal bias in the MR sensor. The transducer is produced by a method in which the same stencil defines the extent of both the MR layer and the hard magnetic layers so that the abutting junctions are formed easily and reliably.

Abstract: A magnetoresistive (MR) read transducer comprising an MR layer having passive end regions separated by a central active region. A longitudinal bias is produced by a thin film of hard magnetic material in the end regions only, and the thin film of hard magnetic material is spaced from the MR layer by a nonmagnetic spacer layer so that a magnetostatic longitudinal bias is produced of a level to maintain the passive end regions of the MR layer in a stable state.

Abstract: A process for the batch fabrication of an array of shielded magnetoresistive (MR) read transducers comprising the steps of depositing a full film over the entire substrate of a first magnetic shield layer, a first non-magnetic gap layer and sputter depositing a layer of MR sensor material in the presence of a magnetic field for orienting the anisotropy axes of the layers of MR sensor material in a chosen direction. The MR sensor layer and the first gap layer are permitted to produce a plurality of MR read transducers, and the first magnetic shield layer is then patterned to produce a first shield for each of the MR read transducers. A second gap layer and a second shield layer are patterned to produce a second shield for each of the MR read transducers.

Abstract: A magnetoresistive (MR) read head in which an insulator layer defines the effective track width over which the read head is sensitive. The insulator layer is deposited or patterned to extend a predetermined distance over the MR element, and the predetermined distance is chosen equal to the desired track width. Conductor leads are deposited in contact with the regions of the MR element not covered by the insulator layer with the conductor leads extending up to, and possibly overlapping, the edges of the insulator layer so that the read signal is sensed over the length of the MR element covered by the insulator layer.