Abstract: A contact magnetic transfer (CMT) master template with antiferromagnetically-coupled (AF-coupled) magnetic islands is used for transferring a magnetic pattern, such as a servo pattern, to a magnetic recording disk. The template is a rigid or flexible substrate with each magnetic island being two ferromagnetic films antiferromagnetically-coupled by an antiferromagnetically-coupling (AFC) film. In the presence of the applied magnetic field the magnetic moments of the two ferromagnetic films are parallel and substantially identical so they generate a magnetic field that cancels the applied field in the region of the slave disk facing the islands. However, when the applied field is removed, any residual magnetization results in the remanent moments in the two ferromagnetic films being oriented antiparallel as a result of the antiferromagnetic exchange coupling across the AFC film. Thus the islands have no net remanent magnetic moment that can affect the servo pattern transferred to the recording disk.

Abstract: A perpendicular magnetic recording medium, such as a perpendicular magnetic recording disk, has a magnetic “torque” layer (MTL) that exerts a magnetic torque onto the perpendicular magnetic recording layer (RL) in the presence of the applied perpendicular write field. The MTL thus acts as a write assist layer in reversing the magnetization of the RL. A coupling layer (CL) is located between the MTL and the RL and provides the appropriate ferromagnetic coupling strength between the MTL and the RL.

Abstract: A data recording disk drive has one or more capacitive sensors for sensing out-of-plane vibration of the disk or disks. The sensors are attached to a support structure that is attached to the disk drive housing. Each sensor is associated with a disk and faces a surface of the disk near the outer perimeter of the disk and close to the recording head. The support structure can be made of a metal or a high-strength plastic and can be a separate structure mounted to the housing, or integrated as part of the single-piece housing casting. If it is metallic, as would be the case if it were integrated with the housing, then layers of insulating material separate the sensors from the support structure. A support structure that serves other functions in the disk drive, such as a support for air dams that extend between the disks, can also function as the support structure for the capacitive sensors.

Abstract: A perpendicular magnetic recording disk has a granular Co-based ferromagnetic alloy recording layer (RL) with oxides of a selected metal (Ta or Nb) and a reduced-thickness exchange-break layer (EBL) between the RL and the soft magnetic underlayer (SUL). A perpendicular magnetic recording system that includes the disk, the write head and the read head, has an improved ability to write to the RL because of the reduced-thickness EBL.

Abstract: A laminated perpendicular magnetic recording medium has two recording layers (RL1 and RL2) that are separated and magnetically decoupled by a nonmagnetic spacer layer (SL). The SL has a thickness and composition to assure there is no antiferromagnetic or ferromagnetic coupling between RL1 and RL2. Thus in the presence of the write field, RL1 and RL2 respond independently and become oriented with the direction of the write field. Each RL is an “exchange-spring” type magnetic recording layer formed of two ferromagnetic layers (MAG1 and MAG2) that have substantially perpendicular magnetic anisotropy and are ferromagnetically exchange-coupled by a nonmagnetic or weakly ferromagnetic coupling layer (CL). The medium takes advantage of lamination to attain higher signal-to-noise ratio (SNR) yet has improved writability as a result of each RL being an exchange-spring type RL.

Abstract: A method of forming a barrier layer of a tunneling magnetoresistive (TMR) device by forming first and second MgO barrier layers by different sputtering methods, but in the same sputtering system module. A first magnesium-oxide (MgO) barrier layer is formed over one of the TMR device's ferromagnetic layers by a DC magnetron sputter deposition from an Mg target in an oxygen environment. In the same module, a second MgO barrier layer is formed over the first MgO film by an RF sputter deposition from an MgO target and in an environment free of oxygen. Prior to the formation of the first MgO barrier layer, an optional Mg protection layer can be deposited on the ferromagnetic layer and oxidized by a first optional oxygen treatment. After deposition of the first MgO barrier layer, a second optional oxygen treatment may be conducted. After deposition of the second MgO barrier layer, a second Mg protection layer may be deposited by DC sputter deposition, followed by an optional third oxygen treatment.

Abstract: A perpendicular magnetic recording disk has an improved recording layer of a granular CoPtCr-based ferromagnetic alloy with inter-granular material made up of one or more oxides of Cr and one or more oxides of one or more of a segregant of Si, Ta, Ti, B, Nb or Hf, wherein the amount of oxygen present in the recording layer is greater than about 22 atomic percent and less than about 35 atomic percent. The amount of oxygen in the recording layer is substantially greater than the amount required for the stoichiometric oxide or oxides of the segregant or segregants, and a substantial portion of the oxygen present in the recording layer is present in the inter-granular material. The recording layer exhibits high signal-to-noise ratio (SNR), a coercivity Hc greater than about 5000 Oe and a nucleation field Hn greater (more negative) than about ?1500 Oe.

Abstract: A magnetic recording disk drive has disks with identical pre-patterned servo patterns on their front and back surfaces and a servo control system for positioning the read/write heads using the servo signals from the identical servo patterns. The servo sectors on the two disk surfaces form identical patterns of angularly spaced arcuate-shaped lines that extend generally radially across the data tracks. The arcuate-shaped lines on one surface, the front surface, generally replicate the path of the recording head as it is moved across the data tracks by a rotary actuator, so that there is a constant sampling rate of the servo sectors on the front surface regardless of radial position of the head. However, the arcuate-shaped lines on the other surface, the back surface, do not replicate the path of the recording head so the servo sampling rate is not constant but varies with radial position of the head.

Abstract: A disk drive has a head fly-height actuator wherein the head-disk spacing is controlled as a function of both the track, and the sector or sectors within the track, where data is to be read or written. The fly-height actuator may be a thermal actuator comprising a heater located on the slider near the read/write head. The fly-height controller (FHC) for the thermal actuator stores band control signal (BCS) values representative of heater power (Hp) to be applied to the thermal actuator when reading or writing to a data track in the associated band of tracks. The FHC also either calculates from a programmed equation or recalls sector control signal (SCS) values representative of an Hp increment to be applied to the thermal actuator depending on the sector or sectors where data is to be written. The FHC sums the appropriate SCS value with the appropriate BCS value to achieve the desired Hp, resulting in the optimal fly-height not only for the selected band but also for the selected sector or sectors.

Abstract: A data recording disk drive has one or more capacitive sensors for sensing out-of-plane vibration of the disk or disks. The sensors are attached to a support structure that is attached to the disk drive housing. Each sensor is associated with a disk and faces a surface of the disk near the outer perimeter of the disk and close to the recording head. The support structure can be made of a metal or a high-strength plastic and can be a separate structure mounted to the housing, or integrated as part of the single-piece housing casting. If it is metallic, as would be the case if it were integrated with the housing, then layers of insulating material separate the sensors from the support structure. A support structure that serves other functions in the disk drive, such as support for disk damping plates, can also function as the support structure for the capacitive sensors.

Abstract: A current-perpendicular-to-the-plane spin-valve (CPP-SV) magnetoresistive sensor has an improved antiparallel (AP) pinned structure, i.e., a structure with first (AP1) and second (AP2) ferromagnetic layers separated by a nonmagnetic antiparallel coupling (APC) layer with the magnetization directions of AP1 and AP2 oriented substantially antiparallel. The AP2 ferromagnetic layer (the layer in contact with the SV spacer layer) is an alloy of a ferromagnetic material and one or more additive elements of Cu, Au and Ag. The additive elements reduce the magnetic moment of the AP2 layer, which enables its thickness to be increased so that its magnetic moment remains close to the magnetic moment of the AP1 ferromagnetic layer. The thicker AP2 layer allows for more bulk spin-dependent scattering of electrons which increases the magnetoresistance of the sensor.

Abstract: An antiferromagnetically exchange-coupled structure for use in a magnetic device, such as a magnetoresistive sensor, includes an enhancement layer formed of a chemically-ordered tetragonal-crystalline alloy, a chemically-ordered tetragonal-crystalline Mn-alloy antiferromagnetic layer in contact with the enhancement layer, and a ferromagnetic layer exchange-coupled with the antiferromagnetic layer. The enhancement layer is an alloy selected from the group consisting of alloys of AuCu, FePt, FePd, AgTi3, Pt Zn, PdZn, IrV, CoPt and PdCd, and the antiferromagnetic layer is an alloy of Mn with Pt, Ni, Ir, Pd or Rh. The enhancement layer enhances the transformation of the Mn alloy from the chemically-disordered phase to the chemically-ordered phase.

Abstract: A current-perpendicular-to-the-plane spin-valve (CPP-SV) magnetoresistive sensor has an insulating layer with at least one aperture that confines the flow of sense current through the active region. The apertures are located closer to the sensing edge of the sensor than to the back edge of the sensor. The aperture (or apertures) are patterned by e-beam lithography, which enables the number, size and location of the apertures to be precisely controlled. The insulating layer may be located inside the electrically conductive nonmagnetic spacer layer, or outside of the magnetically active layers of the spin-valve. More than one insulating layer may be included in the stack to define conductive current paths where the apertures of the insulating layers overlap. The apertures are filled with electrically conductive material, typically the same material as that used for the spacer layer.

Abstract: A hybrid disk drive, i.e., a disk drive with two types of permanent storage media (conventional disk media and nonvolatile memory, such as flash memory), uses its nonvolatile memory in operational modes other than the power-save or “standby” mode wherein the disks are spun down. In a first additional mode, called a “performance” mode, one or more blocks of write data are destaged from volatile memory (the disk drive's write cache) and written to the disk and simultaneously one or more data blocks of write data are destaged from the volatile memory and written to the nonvolatile memory. In a second additional mode, called a “harsh-environment” mode, the disk drive includes one or more environmental sensors, such as temperature and humidity sensors, and the nonvolatile memory temporarily replaces the disks as the permanent storage media.

Abstract: A method for operating a tester for testing heads and disks of a magnetic recording disk drive during manufacturing calculates the readback signal amplitude asymmetry in the frequency domain without the need for measurement in the time domain with a peak detection channel. The tester first signals the write head to write a first pattern on the disk to generate a readback signal with positive pulses. The read head then detects this first recorded pattern and sends the readback signal to a spectrum analyzer connected to the tester. The tester then signals the write head to write a second pattern on the disk to generate a readback signal with negative pulses. The read head then detects this second recorded pattern and sends the readback signal to the spectrum analyzer. The spectrum analyzer measures the amplitudes of the first and second readback signals in the frequency domain using a bandpass filter.

Abstract: An inductive write head has its write poles and write gap oriented to generate magnetic fields in the cross-track direction on a magnetic recording disk in a disk drive. The disk has the magnetizations in the concentric data tracks oriented in the cross-track direction with the concentric data tracks magnetically separated from each other by guard bands. The write head may have an erase pole and an erase gap to generate magnetic fields in an along-the-track direction on the sides of the data tracks, with the along-the-track magnetizations serving as the guard bands.

Abstract: An electrically resistive heater is formed of a chemically disordered CrxV100-x alloy. The alloy exhibits a high temperature coefficient of resistance (TCR) so that the heater temperature can be inferred from its resistance, minimal resistance vs. temperature hysteresis upon heating and cooling, a high melting point, and temporal stability of resistance at elevated temperatures. The resistive heater is used in data storage systems, including magnetic recording hard disk drives that uses heaters to thermally assist the recording or induce protrusion of the write head pole tips to reduce the head-disk spacing, and atomic force microscopy (AFM) based systems that use “nanoheaters” on cantilever tips for either thermally-assisted recording on magnetic media or thermo-mechanical recording on polymer-based media.

Abstract: The invention is a moving-slider rotary piezoelectric microactuator as the secondary actuator for a dual-stage actuator disk drive. The microactuator has a substrate attached to the disk drive suspension and a rotatable frame that supports the slider, so the head-suspension assembly includes the suspension, the microactuator and the slider with attached read/write head. The rotatable frame is attached to a fixed post on the substrate by relatively stiff torsional springs. A piezoelectric driver having a fixed end attached to the substrate provides bidirectional linear displacement of its movable end. The microactuator has a displacement amplification mechanism that includes a connecting rod and a linkage that translates the linear displacement of the driver to amplified orthogonal linear displacement of the rod. The connecting rod is attached to the rotatable frame at a radial distance to cause rotary movement of the frame, and thereby cross-track displacement of the read/write head on the slider.

Abstract: A disk drive has a resistive heater located near the read/write head as a thermal fly-height actuator and uses an improved method for operating the fly-height actuator. As part of the method, the heater may be deactivated during a seek to minimize the risk of head-disk contacts. When a write command is received, a level of heater power is applied to pre-heat the write head prior to writing the initial data sectors. This pre-heating heater power level may be higher than the power level used for writing. Then when writing commences, the lower power level is applied to the heater so the write head has the optimal head-disk spacing during the writing of all the data sectors, including the initial data sectors. Even though the heater may be deactivated during the seek the controller can initiate pre-heating during the last portion of the seek before the write head has reached the target track.

Abstract: A magnetoresistive read head is capable of reading cross-track magnetizations in a magnetic recording disk drive that has the magnetized regions or magnetizations in the magnetic recording layer of the disk oriented in the cross-track direction. The magnetic recording disk has the magnetizations in the concentric data tracks oriented in the radial or cross-track direction. The read head has its free-layer magnetization direction perpendicular to the disk surface and its pinned-layer magnetization direction parallel to the disk surface and orthogonal to the free-layer magnetization direction. The read head may have magnetic side shields spaced from it in the cross-track direction to prevent magnetic flux from adjacent data tracks from reaching the read head.