Abstract: Magnetic recording media having a protective carbon overcoat adapted to protect the magnetic recording layer from surface contact events and corrosion. The carbon overcoat includes at least two layers. A first layer is adapted to protect the magnetic recording layer from surface contact events and corrosion. The second layer is disposed on the first layer and is adapted to enhance the bonding of a lubricant to the carbon overcoat and to minimize head degradation. The magnetic recording media of the present invention advantageously enables the use of thin carbon overcoats, enhancing areal density, while maintaining good tribological properties.

Abstract: Magnetic recording media having a protective carbon overcoat adapted to protect the magnetic recording layer from surface contact events and corrosion. The carbon overcoat includes at least two layers. A first layer is adapted to protect the magnetic recording layer from surface contact events and corrosion. The second layer is disposed on the first layer and is adapted to enhance the bonding of a lubricant to the carbon overcoat and to minimize head degradation. The magnetic recording media of the present invention advantageously enables the use of thin carbon overcoats, enhancing areal density, while maintaining good tribological properties.

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 magnetic 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 monolayers 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 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: An improved CoPt based or CoNi based alloy magnetic recording disk for horizontal recording has a magnetic recording layer which is a laminated structure of relatively thin magnetic alloy films separated by relatively thin non-magnetic spacer films. The resulting laminated disk structure has substantially decreased intrinsic media noise at high linear recording densities. A magnetic recording disk drive uses the low noise laminated disk and and a magnetoresistive read sensor to provide a disk drive with significantly reduced noise in the data readback signal.

Abstract: A method is described for depositing a thin protective carbon film on the air bearing surface of a slider in a magnetic recording disk file. A disk file with a conventional slider and a disk with an essentially carbon protective overcoat is cycled on and off at a frequency such that the slider is maintained in contact with the disk. Alternatively, the disk is rotated at a low constant speed so that the slider is maintained in contact with the disk. In both cases, carbon is transferred from the carbon overcoated disk to the air bearing surface of the slider such that during subsequent operation of the disk file, the disk file has excellent durability, especially when operated at relatively low humidity, as is required in those disk files which use a magnetoresistive sensor on the slider.

Abstract: An improved CoPt based or CoNi based alloy magnetic recording disk for horizontal recording has a magnetic recording layer which is a laminated structure of relatively thin magnetic alloy films separated by relatively thin non-magnetic spacer films. The resulting laminated disk structure has substantially decreased intrinsic media noise at high linear recording densities.

Abstract: A thin film metal alloy magnetic recording disk has an improved protective overcoat which is both wear resistant and which creates a low level of stiction in a rigid disk file. In a preferred embodiment the overcoat is a film of essentially amorphous carbon or hydrogen-containing carbon with relatively small amounts of additives of iron (Fe), tungsten (W) or tungsten-carbide (WC). The structure of the overcoat is a relatively smooth planar carbon surface with discrete clusters of the additives which project slightly above the smooth carbon surface. The specific additives to the carbon overcoat improve the wear resistance of the disk and permit the sliders to contact the disks in contact start/stop (CSS) operation without damage to any of the disk file components.

Abstract: A discrete track thin film metal alloy or metal oxide magnetic recording disk is fabricated by forming a thin film of magnetic material on a substrate, patterning the magnetic film with a chemically etchable support layer and a high resolution photoresist layer, removing portions of the magnetic film and refilling with nonmagnetic material to form concentric nonmagnetic guard bands, and then applying a top layer of additional nonmagnetic material as a passivating and protective disk overcoat after removal of the remaining support layer and photoresist. The exposed photoresist and portions of the chemically etchable support layer beneath the side walls of the patterned photoresist defining the edges of the magnetic tracks are removed in a photoresist developer which also creates undercuts in the support layer beneath the side walls. The undercuts prevent "fences" and provide smooth interfaces between the magnetic tracks and the nonmagnetic guard bands.

Abstract: A discrete track thin film metal alloy or metal oxide magnetic recording disk has a plurality of angularly spaced sectors, each sector being formed of a plurality of discrete blocks of magnetic material which are magnetically polarized in the disk's circumferential direction. These discrete servo blocks and the discrete magnetic tracks are both formed at the same time during the fabrication of the thin film disk such that each servo block is precisely and permanently radially aligned with an associated discrete data track. Following the fabrication of the disk, each of the servo blocks is exposed to the magnetic field generated by passing a direct current (DC) through a recording head. In this manner each of the servo blocks becomes magnetized in the circumferential direction and thereby presents two discrete magnetic transitions to a servo read head or a read/write head.

Abstract: An improved magnetic recording disk drive, in particular a flexible disk drive, includes a head positioning servo system which utilizes servo information recorded on the disk by the disk drive. The servo information is located within one of the data sectors and is in the form of a pattern of radially spaced-apart segments, each segment overlapping a number of data tracks and comprising magnetic transitions which increase in frequency in the radial direction to provide a digital head position error signal (PES). A similar segment is located in each of the other data sectors around the perimeter of the disk to provide track profile information so that the head positioning system can compensate for disk runout and distortion. The disk drive includes means for eliminating the effect of the amplitude of the readback signal from the servo and profile segments on the head positioning system, thus assuring a reliable PES at all radial locations on the disk and allowing interchangeability of disks among disk drives.

Abstract: A detector structure for contiguous-disk bubble devices has a non-ionimplanted elongated bar, a hairpin conductor and a thin-film magneto-resistive element. The elongated bar is positioned in spaced relation to a large period element at the end of a propagation loop. The elongated bar extends both above and below the large period element and prevents the bubble from passing around the element. The hairpin conductor is positioned over the edge of the bar that faces the end period element. The magneto-resistive element is positioned parallel to and at the center of the hairpin conductor.

Abstract: A passive annihilator for ion-implanted contiguous-disk bubble devices has a deep cusp formed by two narrow, non-implanted regions. This annihilator has a maximum bias field margin and drive field margin, and is compatible with other components which comprise a functional ion-implanted contiguous-disk bubble device.

Abstract: An improved non-data reversing one-way bubble transfer switch for contiguous disks is disclosed. The switch has a conductor arrangement in which one edge of the conductor is substantially concentric with and overlapping with the major loop which is in the form of a plurality of scallops. The major loop extends in a direction substantially transversely to one of the three primary crystallographic axes in the bubble material so as to have a propagation track with a high margin on one side and a low propagation margin on the other side. The tip of a minor loop end portion is aligned substantially concentric with the scalloped concave portion of the major loop. This switch has a maximum bias field margin and a maximum phase margin.

Abstract: A gap tolerant merge element for contiguous-disk bubble devices is disclosed. The merge element includes one input track with a tip portion substantially facing the cusp portion of a second input track to form a merge region. An output track is associated with the merge region. In a preferred embodiment, the merge element is passive and does not have a conductor. In another embodiment, the merge element is active and does have a conductor.

Abstract: A swap gate for ion-implanted contiguous disk bubble devices using folded minor loops is disclosed. The bubble device has a major loop, a folded minor loop and a swap element positioned between the major loop and the folded end of the minor loop. The swap element has a first portion for interchanging bubbles with the major loop, a second portion for receiving bubbles from a first region of the folded end of the minor loop, and a third portion for transferring bubbles from the first portion to a second region of the folded end of the minor loop. The folded end of the minor loop also has a third region positioned between the first and second regions to form two bubble storage locations. The bubble device has a conductor associated with the major loop and the first portion of the swap element to form a first transfer gate. The device also includes a second conductor associated with the folded minor loop and the second portion of the swap element to form a second transfer gate.