Abstract: A storage device includes a storage medium and a transducer head with two writers positioned to write to a same surface of the storage medium. The two writers are separated from one another along a down-track direction of a data track on the storage medium and independently controllable to write data.

Abstract: Method and apparatus for enhancing write current switching efficiencies during data write operations in a data storage device. In some embodiments, write data are described in the form a sequence of symbols of nT length where T is a channel clock rate and n is an integer over a selected range. Bi-directional write currents are applied to a write element to record the sequence of symbols to a storage medium. The write currents are switched between a first rail current and a second rail current for alternating symbols. The write currents are further transitioned to an intermediate current value for at least one channel clock period immediately preceding a next occurrence of a symbol boundary between an adjacent pair of symbols in the sequence.

Abstract: Method and apparatus for enhancing write current switching efficiencies during data write operations in a data storage device. In some embodiments, write data are described in the form a sequence of symbols of nT length where T is a channel clock rate and n is an integer over a selected range. Bi-directional write currents are applied to a write element to record the sequence of symbols to a storage medium. The write currents are switched between a first rail current and a second rail current for alternating symbols. The write currents are further transitioned to an intermediate current value for at least one channel clock period immediately preceding a next occurrence of a symbol boundary between an adjacent pair of symbols in the sequence.

Abstract: A read/write head for a disk drive having a magnetoresistive (MR) read element and an inductive write element suitable for perpendicular recording of data onto a disk having a media layer in which the data is stored perpendicularly to the planar surface of the disk and a soft underlayer (SUL) underneath the media layer to provide a low reluctance return path for the magnetic recording field. The write element is formed on top of a substrate, with the read element on top of the write element on the other side of the write element from the substrate. A pancake write coil coils around a magnetic via that either connects to a write shield adjacent to the read element in one embodiment or directly to one of the read shields in a second embodiment.

Abstract: A read/write head for a disk drive having a shorting conductor from a shield of the read element to a conductor that runs from the write element to an external electrical contact pad. This allows for the measurement of the electrical isolation between the read sensor and the read shield via the external contact pads. Such a capability allows the electrical isolation to be measured both during the lapping process and subsequent to the heads being diced into separate sliders. This shorting conductor may be in the form of an internal shorting stud or in the form of an interim conductor that passes through the parting zone between adjacent heads. In the latter case, the shorting conductor is broken when the heads are diced so that a head of this embodiment can only be measured for electrical isolation prior to dicing.

Abstract: A read/write head for a disk drive having a shorting conductor from a shield of the read element to a conductor that runs from the write element to an external electrical contact pad. This allows for the measurement of the electrical isolation between the read sensor and the read shield via the external contact pads. Such a capability allows the electrical isolation to be measured both during the lapping process and subsequent to the heads being diced into separate sliders. This shorting conductor may be in the form of an internal shorting stud or in the form of an interim conductor that passes through the parting zone between adjacent heads. In the latter case, the shorting conductor is broken when the heads are diced so that a head of this embodiment can only be measured for electrical isolation prior to dicing.

Abstract: A read/write head for a disk drive having a shorting conductor from a shield of the read element to a conductor that runs from the write element to an external electrical contact pad. This allows for the measurement of the electrical isolation between the read sensor and the read shield via the external contact pads. Such a capability allows the electrical isolation to be measured both during the lapping process and subsequent to the heads being diced into separate sliders. This shorting conductor may be in the form of an internal shorting stud or in the form of an interim conductor that passes through the parting zone between adjacent heads. In the latter case, the shorting conductor is broken when the heads are diced so that a head of this embodiment can only be measured for electrical isolation prior to dicing.

Abstract: A process for manufacturing a GMR read element of a read/write head for a disk drive having pattern exchange biasing for longitudinal stabilization. An in situ or ex situ GMR anneal of the pinned layer occurs after only the AFM pinning layer and the first pinned layer have been deposited. After the anneal, the upper surface of the first pinned layer is milled with low energy ions to remove oxidation and SIMS inspection determines the amount of oxidation removed and the amount of surface modification required for smoothing. After this, the remaining layers are deposited through the exchange bias layer. A second anneal is then performed at a somewhat lower temperature than the GMR anneal. In this manner, the entire stack is not subjected to the GMR anneal, the upper surface of the first pinned layer can be optimized, and the interface between the free layer and the exchange biased layer is not disturbed.

Abstract: A GMR read element with differential spin valves in which the free layers of the two spin valves have magnetization directions that are parallel to each other while the pinned layers most adjacent to the free layers have magnetization directions that are anti-parallel to each other. This can be achieved by having one of the spin valves be a synthetic spin valve and the other spin valve a non-synthetic spin valve. In this case, a single annealing process can set the magnetization directions of the pinned layers in this manner. It is also possible to use two synthetic spin valves in which one spin valve has an odd number of pinned layers and the other has an even number of pinned layers. The differential spin valves can be connected together in a parallel or a series relationship. It is possible for the differential sensor to be a two-, three-, or four-terminal device.

Abstract: A method and apparatus for providing adaptive drive-level compensation for amplitude and BER loss due to media thermal decay is disclosed. Specifically, in one embodiment, a disk surface having information stored thereon is provided. The information is written in the form of magnetic transitions, which are subject to thermal decay. A head is used to read the information stored on the disk surface and is biased by a bias current (or a bias voltage). A value related to the thermal decay of the magnetic transitions is determined. If the value indicates that the thermal decay has reached an unacceptable level, the bias current is increased in order to compensate for the thermal decay of the magnetic transitions. Once a bias current limit has been reached, information stored on the disk surface is rewritten.