摘要:
Patterned magnetic recording media and associated methods of fabrication are described. The patterned magnetic recording media includes a perpendicular magnetic recording layer that is patterned into a plurality of discrete magnetic islands. The patterned magnetic recording media also includes an exchange bridge structure formed from magnetic material that connects the islands of the perpendicular magnetic recording layer. Connecting the islands with magnetic material increases exchange coupling between the islands, which makes the islands more magnetically stable.
摘要:
A patterned-media magnetic recording disk drive has compensation for write head track misregistration (TMR) from the track centerline. As the disk rotates, the read head detects angularly spaced servo sectors and generates a position error signal (PES) which is used by the servo control system to maintain the read head on track. As the disk rotates, the read head also detects angularly spaced synchronization marks, which are used to control the write clock so that magnetization reversal of the magnetic write field from the write head is synchronized with the position of the data islands. If there is TMR of the write head, there will be an effective shift of A(p in the timing of when the center of the data islands pass through the write field. The disk drive includes write clock phase adjustment circuitry that correlates the PES with Δφ to compensate for TMR of the write head.
摘要:
A method for making a master mold to be used for nanoimprinting patterned-media magnetic recording disks results in a master mold having topographic pillars arranged in a pattern of annular bands of concentric rings. The ratio of circumferential density of the pillars to the radial density of the concentric rings in a band is greater than 1. The method uses sidewall lithography to first form a pattern of generally radially-directed pairs of parallel lines on the master mold substrate, with the lines being grouped into annular zones or bands. The sidewall lithography process can be repeated, resulting in a doubling of the number of lines each time the process is repeated. Conventional lithography is used to form concentric rings over the radially-directed pairs of parallel lines. After etching and resist removal, the master mold has pillars arranged in circular rings, with the rings grouped into annular bands. The master mold may be used to nanoimprint the disks, resulting in disks having a BAR greater than 1, wherein BAR is the ratio of data track spacing in the radial direction to the data island spacing in the circumferential direction.
摘要:
A patterned-media magnetic recording disk drive compensates for circumferential misalignment of data island patterns among the data tracks as a result of errors in fabrication of the master template used to make the disks. Each data track on the disk has its pattern shifted from a generally radial or arcuate line by a certain amount of pattern circumferential misalignment (PCM). The disk drive includes a write clock where writing to the data islands is controlled by detection of synchronization marks by the read head, and circuitry to adjust the phase of the write clock to compensate for PCM. The phase difference between the data pattern of the selected data track where data is to be written and the data pattern of the track where the synchronization marks are being detected is the difference in their respective PCM values.
摘要:
An apparatus, system, and method are disclosed for variable data density patterned media. The apparatus includes a patterned media recording surface comprising a plurality of sectors. Each sector may include a synchronization region configured to generate a signal in a read head, a first data region with a first data density configured to generate a signal with a first frequency, and at least a second data region with a second data density configured to generate a signal with a second frequency. The system includes a hard disk drive and the apparatus. The method includes sensing a signal in a read head, synchronizing the frequency and phase of a write clock with a predetermined frequency and phase of a synchronization region, and modifying the frequency of the write clock after a period of time determined in response to at least one physical characteristic of the disk.
摘要:
A patterned magnetic recording medium has discrete data islands arranged in spaced-apart tracks, with the tracks being arranged in multi-track groups or “hypertracks”. The islands have an equal island-spacing (IS) distance in the along-the-track direction and within each hypertrack the tracks are spaced-apart an equal track-spacing (TS) distance. If there are N tracks in a hypertrack then the islands in each track of a hypertrack are shifted in the along-the-track direction by 1/N times IS from the islands in adjacent tracks in the same hypertrack. The read and write heads have a lateral or cross-track width generally equal to the cross-track width of a hypertrack, so the read and write heads span all the individual tracks in a hypertrack. The hypertracks are spaced apart cross-track direction by a group-spacing (GS) distance, with GS being greater than TS. The islands in a hypertrack may be shifted in the along-the-track direction by approximately ½N times IS from the islands in adjacent hypertracks.
摘要:
In a feedback control mechanism for active damping of slider air bearing vibrations in a hard disk drive slider, a filter is used to filter a velocity signal from a slider to acquire a vibration signal. A phase-shifter, electrically coupled with the filter, shifts the phase of the vibration signal. An amplifier, electrically coupled with the phase-shifter, adjusts the amplitude of the phase-shifted vibration signal to achieve an amplitude adjusted vibration signal. An electrical coupler couples the amplitude adjusted vibration signal to the slider for actively damping air bearing vibrations in the slider.
摘要:
A contact magnetic transfer method forms a pattern of magnetized servo regions in the magnetic recording layer of a rigid perpendicular magnetic recording disk. A master disk or template has a rigid or flexible base with a first film of soft magnetic material on the base and a pattern of islands of soft magnetic material on and extending above the first film and recesses between the islands. The slave disk to be servo patterned is either DC magnetized in a first direction perpendicular to the plane of the recording layer or AC-erased. The slave disk is then placed with its outer layer in proximity to the islands of the master template and a magnetic field is applied in a perpendicular direction to magnetize the regions beneath the islands in the same direction as the applied field. In the regions of the recording layer beneath the recesses of the template the magnetization is reversed from that in the regions beneath the islands.
摘要:
A ramp structure that is designed to reduce the amount of thermal expansion induced misalignment (changes in ramp-disk spacing) between load/unload ramps and data storage disks of a data storage device. The ramp structure has a rigid support structure and ramp units attached to the rigid support structure. The ramp units are made of plastic that is particularly suited for use as load/unload ramps. The ramps are mechanically connected only by means of being attached to the rigid support structure. The data storage disks are attached to a spindle. The rigid support structure is made of a material that has a thermal expansion coefficient that is equal to the thermal expansion coefficient of the spindle and any other parts to which the disks are attached. As a temperature change causes the spindle to expand and the spacing between disks to change, the rigid support structure expands at the same rate, thereby maintaining alignment between the ramps and the disks. Preferably, each ramp unit has two ramps, but each ramp unit can have a single ramp.
摘要:
A dielectric cantilever arm stylus with an integrally formed pyramidal tip is provided. The tip is molded in a pyramidal pit etched in a later-removed (100) silicon substrate. An integrally-formed cantilever arm is also formed as the tip is being formed. Various thin film materials form the cantilever arm and the tip. In one embodiment of the invention, the dielectric is silicon nitride. The cantilever arm is anodically bonded to a glass block.