Abstract: A nonvolatile multiplexer circuit comprising an electric circuitry for selecting an output signal from a plurality of input signals based on select signals, the electric circuitry comprises at least one input terminal, at least one select terminal, and at least one output terminal; a high voltage source and low voltage source electrically coupled to a first and second source terminal, respectively of the electrical circuitry; at least one nonvolatile memory element comprising two stable logic states and electrically coupled to the output terminal at its first end and to an intermediate voltage source at its second end, wherein a logic state of the nonvolatile memory element is controlled by a bidirectional electrical current running through the memory element, and wherein an electrical potential of the intermediate voltage source is lower than that of the high voltage source but higher than that of the low voltage source.

Abstract: A magnetic head for perpendicular recording having reduced side writing and erasing is disclosed. The writer portion of the magnetic head includes a main pole and a return pole. The main pole includes a multilayer main pole tip and a multilayer yoke. The layers of the main pole tip and the yoke are antiferromagnetically coupled to each other with a non-magnetic metal. Antiferromagnetic coupling between the layers of the main pole tip and the yoke dramatically reduces fringing flux emanated from the sides of the main pole intending to close through an upper portion of the return pole. A biasing antiferromagnetic layer is coupled to the upper portion of the return pole to bias the return pole parallel to the air bearing surface. This prevents or reduces the effect of domain wall formation in the return pole, which results in further reduction in side writing and erasing.

Abstract: A transducer including a return pole having a return pole tip extending to an external surface of the transducer. The external surface of the return pole tip has an area that is larger than a cross-sectional area of the return pole taken parallel to the external surface but at a back gap region within the transducer a distance from the external surface.

Abstract: A write element for a magnetoresistive (“MR”) head or a giant magnetoresistive (GMR) head includes a yoke and a coil. The coil made of a microstrip transmission line. The coil is a single turn and is U-shaped. The yoke of the write element includes laminated bottom pole, and top pole which are made of thin layers of ferromagnetic material antiferromagnetically exchange coupled to each other through a very thin nonmagnetic metallic layer. The yoke is made of metallic superlattices exhibiting strong antiferromagnetic exchange coupling between ferromagnetic layers through thin nonmagnetic metallic layers. The coil and the yoke are intertwined to provide two or more flux interactions between them. The yoke has a symmetrical structure with three interconnect vias, thereby reducing the effective magnetic length of the yoke. The antiferromagnetically exchange-coupled yoke has a stable single domain structure that exhibits very high switching time and does not suffer from hysteresis losses.

Abstract: A magnetic head for perpendicular recording on double layer media with suppressed side writing and controlled write width is disclosed. The present invention reduces the problem of side writing and controls the write width of the writing element by providing a writing element with a trailing edge sized dimensionally larger than the leading edge, side shields, and specifically spaced writing gaps placed at various distances between the write element and the side shields, return poles, and the main pole.

Abstract: A magnetic head for perpendicular recording having reduced side writing and erasing is disclosed. The writer portion of the magnetic head includes a main pole and a return pole. The main pole includes a multilayer main pole tip and a multilayer yoke. The layers of the main pole tip and the yoke are antiferromagnetically coupled to each other with a non-magnetic metal. Antiferromagnetic coupling between the layers of the main pole tip and the yoke dramatically reduces fringing flux emanated from the sides of the main pole intending to close through an upper portion of the return pole. A biasing antiferromagnetic layer is coupled to the upper portion of the return pole to bias the return pole parallel to the air bearing surface. This prevents or reduces the effect of domain wall formation in the return pole, which results in further reduction in side writing and erasing.

Abstract: A transducer including a return pole having a return pole tip extending to an external surface of the transducer. The external surface of the return pole tip has an area that is larger than a cross-sectional area of the return pole taken parallel to the external surface but at a back gap region within the transducer a distance from the external surface.

Abstract: A perpendicular magnetic recording medium with antiferromagnetic coupling in a soft magnetic underlayer. The soft magnetic underlayer includes a first magnetic soft layer, a first interface layer on the first magnetic soft layer, a second magnetic soft layer, a second interface layer on the second magnetic soft layer, and a non-magnetic coupling layer between the first interface layer and the second interface layer. The first and second magnetic soft layers are antiferromagnetically exchange coupled to one another through the non-magnetic coupling layer, wherein the first and second interface layers increase the exchange coupling between the first and second magnetic soft layers.

Abstract: A spin valve read element for use with, for example, magnetic recording media, includes a permanent magnet as one of the multilayers that make up the spin valve. The spin valve may also include a pinned ferromagnetic layer, an antiferromagnetic coupling inducing layer, a reference ferromagnetic layer, an electroconductive layer, and/or a free ferromagnetic layer. Epitaxy breaking layers may also be advantageously positioned within the spin valve. The multilayers of the spin valve may be constructed as a current perpendicular to the plane or a current parallel to the plane type spin valve.

Abstract: A spin valve sensor for use with a data storage system includes free and pinned ferromagnetic (FM) layers, a conducting layer therebetween, contact leads, free layer biasing elements, and an anti-ferromagnetic (AFM) layer. The pinned layer has opposing ends, which define a width of an active region of the spin valve sensor having a giant magnetoresistive effect in response to applied magnetic fields. The free layer is positioned below the pinned layer and has opposing ends that extend beyond the active region. The contact leads abut the pinned layer and overlay portions of the conducting layer. The free layer biasing elements abut the ends of the free layer and bias a magnetization of the free layer in a longitudinal direction.

Abstract: A spin valve sensor comprising a ferromagnetic free layer, a ferromagnetic pinned layer, a layer of non-ferromagnetic material positioned between the free layer and the pinned layer, and an antitferromagnetic pinning layer positioned adjacent to the pinned layer such that the pinning layer is in direct contact with the pinned layer. The free layer comprises a multi-layer stack including a non-magnetic insulating spacer positioned between a first and a second ferromagnetic sublayer. The non-magnetic insulating spacer provides a specular electron scattering effect. The first and the second ferromagnetic sublayers each have passive end regions separated by a central active region. The spin valve sensor further includes bias means positioned between the first and the second ferromagnetic sublayers in the passive end regions.

Abstract: A giant magnetoresistance recording head includes a writer having a top pole, a shared pole, a conductive coil and a write gap region. The top pole includes a first top pole piece and a second top pole piece. The second top pole piece is formed at least in part over the first top pole piece and is recessed from the air bearing surface. The first top pole piece is formed over a top flat surface of the shared pole and is separated from the shared pole by the write gap region. The shared pole has a recess on the top surface. The recess is placed under the top pole and filled with a non-magnetic material. The non-magnetic recess in the shared pole defines the throat height of the writer.

Abstract: A magnetic recording head having an air bearing surface includes first and second top poles, a bottom pole, a write gap layer positioned between the first top pole and the bottom pole, a first conductive coil positioned between the second top pole and the write gap layer, and a second conductive coil positioned in a recess of the bottom pole. At least a portion of the second conductive coil is positioned near the air bearing surface under the first top pole. In addition, the recess of the bottom pole is defined by a magnetic sublayer, wherein an inner surface of the magnetic sublayer does not include sharp corners near the air bearing surface.

Abstract: A read/write head for use in a disc drive storage system includes perpendicular writing and reading elements. The perpendicular writing element includes a main pole, a return pole, a write gap, and a conductive coil. The return pole is located downstream of the main pole relative to a rotating disc and is connected to the main pole at a back gap. The write gap and the conductive coil are positioned between the main and return poles. The conductive coil is adapted to induce magnetic flux in the main and return poles. The reading element can be positioned upstream or downstream of the perpendicular writing element and includes top and bottom shields and a read sensor positioned therebetween.

Abstract: A spin valve sensor for use with a data storage system includes free and pinned ferromagnetic (FM) layers, a conducting layer therebetween, contact leads, free layer biasing elements, and an anti-ferromagnetic (AFM) layer. The pinned layer has opposing ends, which define a width of an active region of the spin valve sensor having a giant magnetoresistive effect in response to applied magnetic fields. The free layer is positioned below the pinned layer and has opposing ends that extend beyond the active region. The contact leads abut the pinned layer and overlay portions of the conducting layer. The free layer biasing elements abut the ends of the free layer and bias a magnetization of the free layer in a longitudinal direction.

Abstract: A magnetic recording head having an air bearing surface comprises a writer having a substantially planar single piece top pole, a shared pole and a conductive coil. The top pole and shared pole are separated by a write gap region. A magnetic stud is positioned adjacent the write gap region near the air bearing surface. The magnetic stud provides a uniform magnetic flux supply to the write gap region. The magnetic stud has a variable height along the air bearing surface. An inner surface of the magnetic stud substantially conforms to an outer surface of the conductive coil. The shared pole includes a recess, and at least a portion of the conductive coil is positioned in the recess. The recess in the shared pole is filled with an insulator that substantially surrounds the portion of the conductive coil positioned in the recess. A capping layer is formed on the portion of the conductive coil positioned in the recess.

Abstract: A spin valve read element for use with, for example, magnetic recording media, includes a permanent magnet as one of the multilayers that make up the spin valve. The spin valve may also include a pinned ferromagnetic layer, an antiferromagnetic coupling inducing layer, a reference ferromagnetic layer, an electroconductive layer, and/or a free ferromagnetic layer. Epitaxy breaking layers may also be advantageously positioned within the spin valve. The multilayers of the spin valve may be constructed as a current perpendicular to the plane or a current parallel to the plane type spin valve.

Abstract: A writer for perpendicular recording on bilayer media with suppressed skew angle effect on the width of the recorded track is disclosed. The writer has a wide and flat trailing edge and a narrow leading edge. In a preferred embodiment, the pole has a trapezoidal cross-section. To suppress the skew effect on the width of the recorded track, the slope angle of the pole sides may be greater than the maximum skew angle in a drive.

Abstract: A magnetic head for perpendicular recording on double layer media with suppressed side writing and controlled write width is disclosed. The present invention reduces the problem of side writing and controls the write width of the writing element by providing a writing element with a trailing edge sized dimensionally larger than the leading edge, side shields, and specifically spaced writing gaps placed at various distances between the write element and the side shields, return poles, and the main pole.

Abstract: A magnetic recording head having an air bearing surface comprises a writer having a substantially planar single piece top pole, a shared pole and a conductive coil. The top pole and shared pole are separated by a write gap region. A magnetic stud is positioned adjacent the write gap region near the air bearing surface. The magnetic stud provides a uniform magnetic flux supply to the write gap region. The magnetic stud has a variable height along the air bearing surface. An inner surface of the magnetic stud substantially conforms to an outer surface of the conductive coil. The shared pole includes a recess, and at least a portion of the conductive coil is positioned in the recess. The recess in the shared pole is filled with an insulator that substantially surrounds the portion of the conductive coil positioned in the recess. A capping layer is formed on the portion of the conductive coil positioned in the recess.