Abstract: Magnetic films comprising iridium, manganese and nitrogen (IrMnN) are disclosed. Multi-layer structures including ferromagnetic layers deposited on the IrMnN films are also disclosed. The IrMnN films have a (200) texture and may act as seed layers and/or exchange biasing layers for the ferromagnetic layers deposited thereon. The multi-layer structures are useful in applications such as read sensors for magnetic recording heads and soft magnetic underlayers for perpendicular magnetic recording media.

Abstract: A method and apparatus for interferometnc measurement of a medium surface is disclosed. More particularly, a quadrature phase shift interferometer and a process for unwrapping phase are described. The interferometer has a reduced number of optical components though yields results sufficient to measure surface of a hard disc for final inspection. Defects on such a surface are characterized by their out-of-plane displacement with nanometer resolution.

Abstract: A magnetic recording medium on glass or Al substrates with a film structure of subseedlayer/seedlayer/underlayer/magnetic layer/carbon overcoat, in this order, in which the subseedlayer comprises an element of Group VIb and the seedlayer comprises a material having a B2 structure.

Abstract: A hydrodynamic spindle motor including an internally disposed heating element in a stationary spindle portion having a spindle hub rotatably coupled thereto. The hydrodynamic spindle motor has particular application for supporting discs for co-rotation for a disc drive. The heating element is activated to control viscosity of a hydrodynamic fluid of a hydrodynamic bearing rotationally supporting the spindle hub relative to the stationary spindle. Operation of the heating element reduces viscosity of the hydrodynamic fluid to reduce motor power requirements and improve “up-to-speed” time.

Abstract: A disc clamp assembly and method for balancing a spindle hub assembly within a disc drive utilizes a base piece, a balance ring retainer piece and a balance ring. The disc clamp base piece is positioned on the top surface of the rotatable spindle hub to secure a disc stack to the spindle hub. The balance ring retainer piece is attached to the top surface of the base piece and defines a peripheral rim for accepting a balance ring. The balance ring has a predetermined mass to modify the center of gravity of the spindle hub assembly toward the central axis of rotation for the spindle hub.

Abstract: A method of performing dip coating of a layer of a resist material on a surface of a substrate, comprising steps of: (a) providing a dip coating vessel having an interior space containing a dip coating liquid comprising a solution of the resist material in a solvent, the dip coating vessel being open at the top thereof; (b) providing a substrate having a surface, immersing the substrate in the dip coating liquid in the vessel via the open top, and withdrawing the substrate from the vessel via the open top thereof, thereby forming a layer of resist material on the surface; and (c) monitoring and maintaining the viscosity of the dip coating liquid supplied to the dip coating vessel at a predetermined value. Also disclosed is an apparatus for performing the method.

Abstract: A method for optimizing the attenuation of mechanical resonances of actuator driving energy of a disc drive is presented. The method generally involves determining a resonant frequency range of the disc drive, comparing the resonant frequency range to a filter coverage limit, failing the disc drive if the resonant frequency range exceeds the filter coverage limit, and storing notch filter constants in servo flash memory of a servo control processor if the filter coverage limit is not exceeded by the range of resonant frequencies. The notch filter constants configure the notch filter to attenuate the frequencies of the driving energy produced by the servo control processor that are within the resonant frequency range. The notch filter is implemented by the servo control processor each time the disc drive is used. Also presented is a disc drive and a program that are capable of implementing the above-described method.

Abstract: A read head for perpendicular magnetic recording that reduces side reading. The read head includes a read element and a magnetic shield spaced apart from the read element. The magnetic shield at least partially surrounds the read element at an air-bearing surface of the read element. The ratio of an air-bearing surface area of the magnetic shield to an air-bearing surface area of the read element is from about 1:1 to about 40:1.

Abstract: A disc drive storage system and device for use with a host computer is provided in which information contained on the disc drive can be write protected with an ATA compatible write protection scheme. The system includes at least one rotatable disc having a disc surface with a plurality of physical memory locations referenced by the host computer through logical block addresses. The physical memory locations include data storage locations and attribute storage locations that store protection status information corresponding to the data storage locations. A disc controller receives write protection commands that are compatible with an ATA data exchange protocol from the host. These write protection commands relate to the write protection status information of at least one logical block address. The controller executes the write protection commands to thereby implement a write protection scheme compatible with the ATA data exchange protocol.

Abstract: Disclosed are a spin valve magnetoresistive sensor and methods of fabricating the same. The sensor includes a free layer, a synthetic antiferromagnetic. (SAF) layer, a spacer layer positioned between the free layer and the SAF layer, and a Mn-based antiferromagnetic pinning layer in contact with the SAF layer. The SAF layer includes first and second ferromagnetic CoFe layers and an Ru spacer layer positioned between and directly in contact with the first and second CoFe ferromagnetic layers.

Abstract: A stabilized vertical GMR head is provided and includes a GMR stack having a pair of free magnetic layers having a first edge and a second edge. A pair of soft magnetic layers is also included and positioned so that one of the soft magnetic layers is adjacent to the first edge and another of the soft magnetic layers is adjacent to the second edge. A pair of AFM layers is included and positioned so that one of the AFM layers is adjacent to one of said soft magnetic layers and another of said AFM layers being adjacent to other of said soft magnetic layers.

Abstract: A patterned recording media is comprised of a combination of raised features and depressed features in or on the surface of the recording disk. A depressed feature is known as a pit, while a raised feature is known as an island. The islands form areas where one or more data bits can be written. The recording head is synchronized to the discrete bit pattern by determining the correct clock cycle (phase) and clock count within the clock cycle.

Abstract: A preamplifier circuit of a preamp configured for measuring microwave noise of a magnetoresistive element biased by a pair of current sources is disclosed. In a preferred embodiment, the preamplifier circuit includes a differential amplifier disabled from the preamplifier circuit by a amplifier bypass switch, one of the pair bias current sources disabled from the preamplifier circuit and referenced to ground by a current bypass switch, a test point communicating with the amplifier bypass switch providing single ended access to the biased magnetoresistive element for measuring the microwave noise of the biased magnetoresistive element relative to the ground reference and a ground point communicating with the ground reference providing the ground reference for measuring the microwave noise of the biased magnetoresistive element.

Abstract: An anti-ferromagnetically coupled (“AFC”), high areal density magnetic recording medium having improved thermal stability and signal-to-medium noise ratio (“SMNR”), comprising: (a) a non-magnetic substrate having at least one surface; and (b) a ferromagnetic recording layer comprising a layer stack overlying the at least one surface, the layer stack comprising a plurality of vertically spaced-apart ferromagnetic layers, the ferromagnetic layers being spaced-apart by respective non-magnetic spacer layers providing anti-ferromagnetic coupling (AFC) therebetween, the total exchange energy acting upon each of the ferromagnetic layers of the layer stack in the remanent state and their effective magnetic energies adjusted to provide opposing alignment of the magnetic moments of adjacent ferromagnetic layers of the stack.

Abstract: A slider includes a slider body having a leading edge, a trailing edge, a first side edge, a second side edge and a center line extending between the leading edge and the trailing edge, which define a disc-facing surface having a bearing plane. A protrusion is positioned on the disc-facing surface along the first side edge and has a protrusion surface. The protrusion surface is tilted with respect to the bearing plane about the center line and towards the first side edge.

Abstract: A shutter assembly for use in a thin-film processing system to control exposure of a substrate to a process energy source includes a shield member having a shutter opening. The shutter opening is defined by sides which are oriented along radial lines of a central axis to promote uniform exposure of the substrate to the process energy source.

Abstract: A method and apparatus for obtaining optimum parameter values for a read channel employed in a disc drive storage system are provided in which data having a known pattern is written on a disc surface of the disc drive storage system. The data written on the disc surface is then read to obtain a readback signal. The readback signal is passed through the read channel. A readback signal response is obtained at an output test point of the read channel. The readback signal response at the output test point is compared with a target response of the read channel at the output test point. The comparison is carried out using frequency spectral analysis. At least one parameter of the read channel is adjusted if the readback signal response substantially differs from the target response.

Abstract: A method for producing magnetoresistive heads includes the steps of placing a substrate having a plurality of transducers in an environment including a focused ion beam. The focused ion beam is directed onto the first MR element. A property level, generally the resistance associated with the MR stripe, of the first MR element is monitored until the resistance reaches a desired level. The focused ion beam is redirected onto a second area of the substrate which includes the second MR element. The electrical resistance of the second MR element is monitored as the focused ion beam acts on the second MR element until the resistance of the MR element reaches a desired level. Using this process, the resistivity of individual MR elements within the substrate can be tightly controlled.

Abstract: A single, or common, ion beam source is utilized for ion beam deposition (IBD) of defect-free multilayer coatings, e.g., multilayer, carbon-based protective overcoats for magnetic and/or magneto-optical (MO) data recording/information storage and retrieval media such as hard disks. According to the inventive methodology, a plurality of source gas supply means for supplying a single IBD source with different source gases for each of the layers of the multilayer are selectively operated in “vent” and “run” modes by means of a plurality of valves, the opening and closing of which are determined by a programmable gas flow controller. The inventive method and apparatus advantageously provide IBD of multilayer coatings with minimum cross-contamination of individual layers, at a reduced equipment cost and size obtained by elimination of the need for separate ion beam sources and associated vacuum pump means for each constituent layer of the multilayer.

Abstract: An apparatus and method of identifying defective servo sectors in a data storage device detects servo sectors having an associated position error signal (PES) value that exceeds a predetermined PES threshold value, as well as servo sectors that have a related transducer velocity signal that exceeds a predetermined velocity threshold value.