A method of forming a read head. The method includes forming first and second read sensors. A first read measurement is performed on a storage medium using the first read sensor. A second read measurement is performed on the storage medium using the second read sensor. Based on a comparison of the first and second read measurements to a predetermined quantity, either the first read sensor or the second read sensor is selected to be operational in a data storage device.

An apparatus according to one embodiment includes a magnetic head having at least two tunneling magnetoresistance sensors, where a resistance of a tunnel barrier of each of the tunneling magnetoresistance sensors of the magnetic head is about 25 ohms or less, a drive mechanism for passing a magnetic medium over the magnetic head, and a controller electrically coupled to the magnetic head. In addition, the controller includes a biasing circuit, where the biasing circuit restricts a maximum voltage drop across the tunnel barrier.

In one general embodiment, an apparatus includes a magnetic head having at least one tunneling magnetoresistance sensor. The resistance of the tunnel barrier of each tunneling magnetoresistance sensor is about 25 ohms or less. In another general embodiment, an apparatus includes a magnetic head having at least one tunneling magnetoresistance sensor. The resistivity of the tunnel barrier of each tunneling magnetoresistance sensor is less than a product of a target resistance of the tunnel barrier and an area of the tunnel barrier. The target resistance is about 25 ohms or less.

A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. The HM may have a height and width greater than that of the top shield. The top shield may have a ring shape with a HM formed above, below, or within the ring shape, and wherein the HM stabilizes a vortex magnetization. HM magnetization is set or reset from room temperature to 100 C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.

A system according to one embodiment includes a magnetic head having a plurality of sensors arranged to simultaneously read at least three immediately adjacent data tracks on a magnetic medium, wherein none of the sensors share more than one lead with any other of the sensors. Such embodiment may be implemented in a magnetic data storage system such as a disk drive system, which may include a magnetic head, a drive mechanism for passing a magnetic medium (e.g., hard disk) over the magnetic head, and a controller electrically coupled to the magnetic head.

A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. Alternatively, the HM may replace a shield domain. The top shield may have various shapes including a ring shape in which the HM stabilizes a vortex magnetization. In a whole shield coupling design, the HM contacts all of the top shield bottom surface except over the sensor and junction shield. HM magnetization is set or reset from room temperature to 100 C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.

An apparatus, according to one embodiment, includes: a module; and a plurality of tunnel valve read transducers arranged in an array extending along the module. Each of the tunnel valve read transducers includes: a sensor structure having a tunnel barrier layer and a free layer. Moreover, each of the tunnel valve read transducers includes a pair of hard bias magnets which sandwich the respective sensor structure therebetween, the hard bias magnets being positioned on opposite sides of the sensor structure along a cross-track direction. Furthermore, a thickness of each of the hard bias magnets at a thickest portion thereof is at least 10 times greater than a thickness of the free layer. Other systems, methods, and computer program products are described in additional embodiments.

An apparatus, according to one embodiment, includes: a module, and a plurality of tunnel valve read transducers arranged in an array extending along the module. Each of the tunnel valve read transducers includes: a sensor structure, an upper magnetic shield, a lower magnetic shield, an upper conducting spacer layer between the sensor structure and the upper magnetic shield, a lower conducting spacer layer between the sensor structure and the lower magnetic shield, and electrically insulating layers on opposite sides of the sensor structure. The sensor structure includes a cap layer, a free layer, a tunnel barrier layer, a reference layer and an antiferromagnetic layer. Moreover, a height of the free layer measured in a direction perpendicular to a media bearing surface of the module is less than a width of the free layer measured in a cross-track direction perpendicular to an intended direction of media travel.

An apparatus, according to one embodiment, includes: a module, and a plurality of tunnel valve read transducers arranged in an array extending along the module. Each of the tunnel valve read transducers includes: a sensor structure, an upper magnetic shield, a lower magnetic shield, an upper conducting spacer layer between the sensor structure and the upper magnetic shield, a lower conducting spacer layer between the sensor structure and the lower magnetic shield, and electrically insulating layers on opposite sides of the sensor structure. The sensor structure includes a cap layer, a free layer, a tunnel barrier layer, a reference layer and an antiferromagnetic layer. Moreover, a height of the free layer measured in a direction perpendicular to a media bearing surface of the module is less than a width of the free layer measured in a cross-track direction perpendicular to an intended direction of media travel.

In one general embodiment, an apparatus includes a magnetic head having at least one tunneling magnetoresistance sensor. The resistance of the tunnel barrier of each tunneling magnetoresistance sensor is about 25 ohms or less. In another general embodiment, an apparatus includes a magnetic head having at least one tunneling magnetoresistance sensor. The resistivity of the tunnel barrier of each tunneling magnetoresistance sensor is less than a product of a target resistance of the tunnel barrier and an area of the tunnel barrier. The target resistance is about 25 ohms or less.