A bond pad set includes at least one ground pad and at least one electrical bond pad configured to bias and send/receive signals. The bond pad set is electrically connected to a multiplicity of electrical components. At least one electrical bond pad of the bond pad set is shared between two or more of the electrical components.

A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.

Embodiments related to the generation of magnetic bias fields for magnetic sensing are described and depicted. In one embodiment, a sensor includes at least one magnetosensitive element, and a magnetic body with an opening, the magnetic body comprising magnetic material, the magnetic body having inclined surface sections shaped by the opening, wherein the sensor is arranged within the opening such that the magnetosensitive element is in lateral directions bounded by the inclined surface sections.

Implementations described and claimed herein provide a system comprising an external magnetic field generator, wherein the external field magnetic field generator is configured to rock an effective annealing magnetic field between a first positive angle and a second negative angle compared to a desired pinning field orientation in an AFM/PL structure.

Embodiments related to the generation of magnetic bias fields for magnetic sensing are described and depicted. In one embodiment, a sensor includes at least one magnetosensitive element, and a magnetic body with an opening, the magnetic body comprising magnetic material magnetized mainly in a vertical direction, the magnetic body having inclined surface sections shaped by the opening, wherein the sensor is arranged atop the opening.

A data storage device comprises a magnetic medium and a head configured to be actuated over the magnetic medium. The head comprises a write element and a write driver configured to generate a write current to be applied to the write element. The write driver comprises a data switch section configured to switchably output low-level signals and high-level signals, and a stationary cascode section configured to receive the low-level signals and high-level signals from the data switch section and to generate a cascode pass through current. The data switch section comprises low voltage CMOS devices and the stationary cascode section comprises high voltage CMOS devices.

The present disclosure describes aspects of a differential current-mode (iMode) driver for microwave-assisted magnetic recording (MAMR) application in hard-disk drives. In some aspects, an iMode driver circuitry employs a driver circuit coupled to power supply connections. The driver circuit is configured to provide a controlled differential bias current and includes separate source and sink output terminals. A MAMR sensor couples between the source and sink output terminals, through which the MAMR sensor receives the controlled differential bias current provided by the driver circuit. The MAMR sensor, which has a field-entry terminal and a field-exit terminal, generates microwave fields for the recording process. A common-mode feedback (CMFB) loop couples to the field-entry and field-exit terminals of the MAMR sensor, forming a feedback pathway with the driver circuit. This CMFB loop detects common-mode voltage (CMV) and adjusts the controlled differential bias current to maintain CMV regulation of the MAMR sensor.

Disclosed are methods for linearizing the response of a non-linear magnetic reader, for example in the operation of a hard disk drive. Magnetic readers generally exhibit non-linearities in their response to an applied magnetic field, and those non-linearities may be particularly pronounced when the field strength is high. This deviation from linearity at larger field strengths can limit the useful range of field amplitudes. To expand the useful range of field amplitudes and thereby increase the available signal at the reader, the reader bias current may be varied in such a way to compensate for the natural non-linearity of the reader, thus making the reader output signal linear over a larger range of detected field strengths.

A method of forming a read head is described where a Tunneling Magnetoresistive (TMR) stack of layers comprised of a free layer (FL) and having sidewalls separated by a cross-track width is formed on a bottom shield. In subsequent steps, a first insulation layer and longitudinal biasing layer are formed on the sidewalls and bottom shield. After a TMR sensor backside is formed that exposes the bottom shield, a second insulation layer and permanent magnet (PM) layer are deposited on exposed portions of the bottom shield. Thereafter, the PM layer magnetization is initialized in a direction that adjusts FL bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior asymmetry measurement.