摘要:
A magnetic recording hard disk drive (HDD) has at least one read/write head that accesses more than one disk surface. The HDD is able to transfer data to and from the host computer seamlessly without interruption during the time the head is being moved from one disk surface to another disk surface. Nonvolatile solid state memory is associated with pairs of disk surfaces. During the time of a head transfer from one disk surface in the pair to the other disk surface, data is read from or written to the associated nonvolatile memory. The data is first read from or written to one disk surface, then from or to the nonvolatile memory, and then, after completion of the head transfer, from or to the other disk surface, thereby allowing seamless uninterrupted transfer of data.
摘要:
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.
摘要:
A contact magnetic transfer (CMT) method for forming a magnetic pattern, such as the servo pattern on a magnetic recording disk, uses a master template with antiferromagnetically-coupled (AF-coupled) magnetic islands. 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.
摘要:
A data recording system, such as a magnetic recording hard disk drive, has a recording medium in which the data tracks have pseudo-random binary sequences for the servo information used to control the position of the recording head. A first pseudo-random binary sequence (PRBS) and a second PRBS identical to the first PRBS but shifted by a portion of the period of the first PRBS are located between the track boundaries in alternating tracks in a first region of the servo pattern and between the track centers in alternating tracks in a second region spaced along the track from said first region. A servo decoder has two correlators, one for each PRBS. Each correlator outputs a dipulse when its PRBS repeats. The difference in amplitude of the dipulses represents the head position signal. The dipulses also control the amplifier for the signal read back by the head and the timing of the track identification (TID) detector.
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 Schottky rectifier has multiple stages with substantially identical or very similar structures. Each stage includes a nitride-based semiconductor layer, a Schottky contact formed on one surface of the semiconductor layer, and an ohmic contact formed on an opposite surface of the semiconductor layer. The Schottky layer is formed from a metallic material with a high metal work function, and the ohmic contact is formed from a metallic material with a low metal work function. At least one of the stages is a middle stage located between two adjacent stages, such that the Schottky contact of the middle stage and the ohmic contact of one of the adjacent stages are joined together, and such that the ohmic contact of the middle stage and the Schottky contact of another one of the adjacent stages are joined together.
摘要:
Mirror-image patterns for use one patterned media. Methods are implemented to create a mirror-image on the top and bottom of a media disk. These mirror images simplify the creation of electronics for patterned media. Further, the methods allow for a single e-beam master disk to be used to create the stamper for the top and the bottom of the media disk.
摘要:
A patterned perpendicular magnetic recording disk has a pre-patterned disk substrate with pillars and trenches arranged in data regions and servo regions. In the data regions, the height of the data pillars is equal to or greater than the spacing between the data pillars, while in the servo regions the height of the servo pillars is less than the spacing between the servo pillars. A magnetic recording material with perpendicular magnetic anisotropy is deposited over the entire disk substrate, which results in magnetic material on the tops of the data pillars and servo pillars and in the servo trenches. The material in the data trenches is either nonmagnetic or discontinuous. After the application of a high DC magnetic field in one perpendicular direction and a low DC magnetic field in the opposite direction, the resulting disk has patterned servo sectors with servo pillars all magnetized in the same perpendicular direction and servo trenches magnetized in the opposite perpendicular direction.
摘要:
A method for patterning and forming very small structures on a substrate such as a wafer. The process uses a difference in surface energy between a mask and the substrate to selectively deposit a hard mask material such as a metal onto the surface of the substrate. The mask can be formed extremely thin, such as only an atomic mono-layer thick, and can be patterned by ion beam photolithography. The pattern can, therefore, be formed with extremely high resolution. The thin mask layer can be constructed of various materials and can be constructed of perfluoropolyether diacrylate (PDA), which can be dip coated to and exposed to form a desirable positive photoresist mask layer.
摘要:
Mirror-image patterns for use one patterned media. Methods are implemented to create a mirror-image on the top and bottom of a media disk. These mirror images simplify the creation of electronics for patterned media. Further, the methods allow for a single e-beam master disk to be used to create the stamper for the top and the bottom of the media disk.