Abstract: A servo system wherein a read head R detects a servo pattern that is written on a magnetic disk by a write head W. Position control of the write head W is exercised in accordance with the detected servo pattern, and the read head R detects a propagation pattern that is written on the magnetic disk by the write head W. Position of the write head W is corrected in accordance with the detected propagation pattern.

Abstract: A dual GMR or dual spin valve sensor has a self-pinned layer which has its magnetic moment pinned perpendicular to an air bearing surface by sense current fields from conductive layers in the dual spin valve sensor when a sense current is conducted therethrough. This scheme eliminates one of the antiferromagnetic pinning layers which is typically employed in a dual GMR or dual spin valve sensor. The self-pinned layer is thin so that its demagnetization field will not be greater than the sense current fields acting thereon. Because of the thinning of the self-pinned layer the spin valve effect of the spin valve sensor is degraded by scattering of conduction electrons at the boundary of the self-pinned layer.

Abstract: In addition to the conventional test pattern writing in a center of each track and inspection of burst patterns (A and B patterns) through a writing test in a SAT, there is also performed a test pattern data writing test, which is done at each boundary between tracks. With this additional test, it is possible to accurately inspect both C and D burst patterns that are sensitive to a PES signal at each boundary between tracks.

Abstract: A method and apparatus for resolving a “continuity” problem that occurs when modes are switched in the head positioning control process, and a contradiction exists between a short seek and a long seek.

Abstract: A magnetoresistance sensor is fabricated using a sensor structure including a free layer deposited upon a lower layered structure and depositing an oxide structure overlying the free layer. The depositing of the oxide structure includes the steps of depositing a buffer layer overlying the free layer, wherein the buffer layer is a buffer-layer metal when deposited, depositing an overlayer overlying and contacting the buffer layer, the overlayer being an overlayer metallic oxide of an overlayer metal, and oxidizing the buffer layer to form a buffer layer metallic oxide.

Abstract: The hard disk drive comprises: a magnetic disk 2 having servo information stored; magnetic heads 4 seeking on the magnetic disk 2 and staying at a predetermined position to read or write data; a voice coil motor 6 moving the magnetic heads 4 to the predetermined position of the magnetic disk 2; a position controller supplying a driving current to the voice coil motor 6 based on the servo information read by the magnetic heads 4. The position controller includes: a CPU 12 outputting a speed control value based on the servo information; a DAC 7 and a VCM driver 8 converting the speed control value into the driving current; and a controller 10 limiting a driving speed of the voice coil motor 6 in a case that an output timing of the speed control value is shifted.

Abstract: A spin valve sensor is provided with a negative ferromagnetic coupling field ?HFC for properly biasing a free layer and a spin filter layer is employed between the free layer and a capping layer for increasing the magnetoresistive coefficient dr/R of the spin valve sensor. A top portion of the free layer is oxidized for improving the negative ferromagnetic coupling field ?HFC when the spin filter layer is employed for increasing the magnetoresistive coefficient dr/R.

Abstract: A mechanism to allow accurate control of the position of a magnetic head even if the state of the magnetic head has changed due to instability.

Abstract: A data storage device that can perform a track following process even when vibrations are produced by a wide range of frequencies.

Abstract: A control arrangement having a feedforward system and a feedback system, a control model for generating reference position data from a feedforward control signal is separated into an original control model and a compensation filter. Gain of the feedforward control signal is compensated by a gain compensation circuit to form a feedforward control signal after compensation. The reference position data is input to a feedback controller, and a feedback control signal and feedforward control signal are input to a control object. Coefficients of the compensation filter and the gain compensation circuit are compensated on the basis of a head position trajectory obtained by actual seek operation.

Abstract: A magnetic head device which can accommodate higher data transfer rates can be implemented by using lead wires. A magnetic head device 1 according to the present invention includes a head slider 3 having a magnetic head 2 having a data reading element and a data writing element, a reading lead RL for transferring data between the data reading element and external devices, the reading lead configured by a pair of lead wires which are twisted together, and a writing lead WL for transferring data between the data writing element and external devices, the writing lead configured by a pair of lead wires which are untwisted but arranged in parallel to each other. Thus, the magnetic head device can accommodate higher data transfer rates by using the writing lead WL configured by a pair of lead wires which are untwisted but arranged in parallel to each other.

Abstract: A trilayer seed layer structure is employed between a first read gap layer and a spin valve sensor for improving the magnetic and giant magnetoresistive properties and the thermal stability. In the spin valve sensor, the trilayer seed layer structure is located between a first read gap layer and a ferromagnetic free layer. The antiferromagnetic pinning layer is preferably nickel manganese (Ni—Mn). The trilayer seed layer structure includes a first seed layer that is a first metallic oxide, a second seed layer that is a second metallic oxide and a third seed layer that is a nonmagnetic metal. A preferred embodiment is a first seed layer of nickel oxide (NiO), a second seed layer of nickel manganese oxide (NiMnOx), and a third seed layer of copper (Cu).

Abstract: An antiparallel (AP)-pinned spin valve (SV) sensor is provided with an AFM layer of Pt—Mn having a thickness less than 100 Å and using the magnetic field of the sense current to assist the AFM layer in pinning the magnetization of the AP-pinned layer. The SV sensor has positive and negative read signal symmetry about a zero bias point of a transfer curve due to the influences of the a net sense current field, a ferromagnetic coupling field and a demagnetization field being counterbalanced by a net image field from asymmetric positioning of the SV sensor between first and second shield layers. The SV sensor includes an AP-pinned layer with first and second ferromagnetic pinned layers where the second pinned layer adjacent to a spacer layer is thicker than the first pinned layer.

Abstract: An antiparallel (AP)-pinned magnetoresistive tunnel junction (MTJ) sensor is provided with a single antiferromagnetic (AFM) layer sandwiched between an AP-pinned layer and a bias layer for pinning the magnetization directions of the AP-pinned layer and the bias layer. The bias layer may be a simple ferromagnetic bias layer or, alternatively, may be an AP-pinned bias layer including first and second ferromagnetic bias layers with an antiferromagnetic coupling layer sandwiched between. The bias layer provides a demagnetization field HdmB at the free layer having the same direction as the demagnetization field HdmP from the AP-pinned layer. The sum of HdmP and HdmB counterbalance a ferromagnetic coupling field HFC from the AP-pinned layer to obtain zero or near zero asymmetry of the bias point on the transfer curve of the MTJ sensor.

Abstract: A shrouded hard disk drive includes one or more contamination filter cavities embedded within the shroud for capturing airborne contaminants circulated within the drive during normal operation. The present invention takes advantage of naturally occurring radial and circumferential velocity differences between air at the edges of the disk pack and the air at the filter cavity entrance opening (i.e., the inner circumference of the shroud) to redirect airflow through a filter positioned within the one or more filter cavities. After air passes through the filter, it exits through a filter cavity exit opening positioned in proximity to either in the area between the disks, or the area above or below the disk pack.