Abstract: According to one embodiment, a soft underlayer structure includes a coupling layer, at least one outer soft underlayer positioned above and below the coupling layer, and at least one inner soft underlayer positioned above and below the coupling layer between the coupling layer and the associated outer soft underlayer, where the inner soft underlayers have a saturation magnetic flux density and/or a thickness that is different than a saturation magnetic flux density and/or a thickness of the outer soft underlayers.

Abstract: According to one embodiment, a soft underlayer structure includes a coupling layer, at least one outer soft underlayer positioned above and below the coupling layer, and at least one inner soft underlayer positioned above and below the coupling layer between the coupling layer and the associated outer soft underlayer, where the inner soft underlayers have a saturation magnetic flux density and/or a thickness that is different than a saturation magnetic flux density and/or a thickness of the outer soft underlayers.

Abstract: Perpendicular magnetic recording media has been enhanced by controlling the initial growth of magnetic oxide layers and increased magnetic isolation between the grains in the initial magnetic layer. An onset magnetic oxide layer is sputter deposited in an argon-oxygen gas mixture between the main CoPtCr-oxide magnetic layers and the underlying Ru layer. The insertion of the onset magnetic oxide layer enhances the coercivity of the oxide magnetic layers and also improves the nucleation field. The media signal-to-noise ratio and bit error rate also are significantly improved due to the improvement of the initial segregation of Co magnetic grains in the magnetic oxide layers.

Abstract: Perpendicular magnetic recording (PMR) media and methods of fabricating PMR media are described. The PMR media includes, among other layers, an underlayer, a first onset layer on the underlayer, a second onset layer on the first onset layer, and a perpendicular magnetic recording layer on the second onset layer. The second onset layer has a magnetic moment which is higher than both a magnetic moment of the first onset layer and a magnetic moment of the perpendicular magnetic recording layer.

Abstract: Approaches for a testing device for selecting a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). The testing device comprises a continuous magnetic-recording disk, rotatably mounted on a spindle, which stores data using a continuous media format. The testing device also comprises a testing module configured to simulate reading data, stored using a discrete track media (DTM) format, from the continuous magnetic-recording medium. Advantageously, testing time and cost is reduced as both discrete track media (DTM) disks and expensive discrete track media (DTM) recording testing hardware are not required to select the optimal a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). In addition, embodiments may be used to optimize features of the tracks of the DTM disk, such as the land to groove ratio.

Abstract: A structure for high performance perpendicular magnetic recording media has a substrate with a plurality of sequential layers including an adhesion layer, a first soft underlayer (SUL), a coupling layer, a second SUL, a seed layer, a Ru layer, and an onset layer; at least one oxide layer on the onset layer and having a composition with graded anisotropy to improve overwrite of the media; an exchange coupling layer (ECL) on the at least one oxide layer; a cap layer; a decoupling-controlled layer between the ECL and the cap layer to reduce lateral exchange coupling in the cap layer on the ECL; and a carbon overcoat on the cap layer.

Abstract: Approaches for a testing device for selecting a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). The testing device comprises a continuous magnetic-recording disk, rotatably mounted on a spindle, which stores data using a continuous media format. The testing device also comprises a testing module configured to simulate reading data, stored using a discrete track media (DTM) format, from the continuous magnetic-recording medium. Advantageously, testing time and cost is reduced as both discrete track media (DTM) disks and expensive discrete track media (DTM) recording testing hardware are not required to select the optimal a discrete track media (DTM) format for use with a particular head of a hard-disk drive (HDD). In addition, embodiments may be used to optimize features of the tracks of the DTM disk, such as the land to groove ratio.

Abstract: Methods and test systems are disclosed for determining the quality of an erase process for perpendicular magnetic recording (PMR) disks. After performing an erase process on a PMR disk and before the PMR disk is assembled into a hard disk drive, a first test pattern of magnetization pulses is written to a region of the PMR disk. A second test pattern is subsequently read from the region of the PMR disk. The second pattern of magnetization pulses is analyzed in relation to the first test pattern and measured to determine the quality of the erase process.

Abstract: Perpendicular magnetic recording (PMR) media and methods of fabricating PMR media are described. The PMR media includes, among other layers, an underlayer, a first onset layer on the underlayer, a second onset layer on the first onset layer, and a perpendicular magnetic recording layer on the second onset layer. The second onset layer has a magnetic moment which is higher than both a magnetic moment of the first onset layer and a magnetic moment of the perpendicular magnetic recording layer.

Abstract: Methods and test systems are disclosed for determining the quality of an erase process for perpendicular magnetic recording (PMR) disks. After performing an erase process on a PMR disk and before the PMR disk is assembled into a hard disk drive, a first test pattern of magnetization pulses is written to a region of the PMR disk. A second test pattern is subsequently read from the region of the PMR disk. The second pattern of magnetization pulses is analyzed in relation to the first test pattern and measured to determine the quality of the erase process.

Abstract: Perpendicular magnetic recording media has been enhanced by controlling the initial growth of magnetic oxide layers and increased magnetic isolation between the grains in the initial magnetic layer. An onset magnetic oxide layer is sputter deposited in an argon-oxygen gas mixture between the main CoPtCr-oxide magnetic layers and the underlying Ru layer. The insertion of the onset magnetic oxide layer enhances the coercivity of the oxide magnetic layers and also improves the nucleation field. The media signal-to-noise ratio and bit error rate also are significantly improved due to the improvement of the initial segregation of Co magnetic grains in the magnetic oxide layers.

Abstract: Spinstand test improvement that measures Functional Byte Error Rate (F-BER) of a disk. The F-BER is correlated to the BER of a disk. The F-BER test is faster than a BER test. The F-BER test is incorporated into a spinstand tester or the software associated with a spinstand tester.

Abstract: Spinstand test improvement that measures Functional Byte Error Rate (F-BER) of a disk. The F-BER is correlated to the BER of a disk. The F-BER test is faster than a BER test. The F-BER test is incorporated into a spinstand tester or the software associated with a spinstand tester.

Abstract: A method for determining whether a spike in a read back signal from a read head positioned over a perpendicular recording disk having a magnetically soft underlayer (SUL) is caused by a defect in the SUL or by a thermal asperity (TA). A first read back signal with the spike is obtained in the absence of a local magnetic field near the read head. Then, a permanent magnet or electromagnet is used to induce a small local magnetic field by the read head, and a second signal is obtained. If the signals are substantially similar, a thermal asperity is indicated. Otherwise a defect in the 13 magnetically soft underlayer of the disk is indicated.

Abstract: A magnetic test module runs on a spin stand to detect amplitude decay and noise evolution at the same time. Signal-to-noise ratio (SNR) decay is directly measured. The recording performance is correlated better with SNR instead of signal only. The thermal stability of the system is evaluated more accurately with this SNR decay method. A heater is placed under the media disk, and a remote sensing thermometer and temperature controller form a subsystem to set up desired environmental temperature. The heater creates a heated band and the read/write head flies above the heated band. The temperature control system may be removed when SNR decay measurement is performed under room temperature.

Abstract: A magnetic test module runs on a spin stand to detect amplitude decay and noise evolution at the same time. Signal-to-noise ratio (SNR) decay is directly measured. The recording performance is correlated better with SNR instead of signal only. The thermal stability of the system is evaluated more accurately with this SNR decay method. A heater is placed under the media disk, and a remote sensing thermometer and temperature controller form a subsystem to set up desired environmental temperature. The heater creates a heated band and the read/write head flies above the heated band. The temperature control system may be removed when SNR decay measurement is performed under room temperature.

Abstract: A method for determining whether a spike in a read back signal from a read head positioned over a perpendicular recording disk having a magnetically soft underlayer (SUL) is caused by a defect in the SUL or by a thermal asperity (TA). A first read back signal with the spike is obtained in the absence of a local magnetic field near the read head. Then, a permanent magnet or electromagnet is used to induce a small local magnetic field by the read head, and a second signal is obtained. If the signals are substantially similar, a thermal asperity is indicated. Otherwise a defect in the 13 magnetically soft underlayer of the disk is indicated.

Abstract: Optical devices and methods for regulating optical channel signals with specified wavelengths are disclosed. According to one aspect of the present invention, a number of variable optical apparatuses are employed. Each of the variable optical apparatuses includes a first and a second optical channel module, both configured at a wavelength ?i. Each of the variable optical apparatuses further includes an optical regulator (i.e. a neutral density filter controlled by a stepper motor) coupled between the first and second optical channel modules. When signals with different wavelengths arrive, only the signal with the wavelength ?i will transmit through the first optical channel module and the rest are reflected off. The transmitted signal is regulated (i.e. attenuated or strengthened) accordingly by the optical regulator before transmitting through the second optical channel module. Hence, the signals with different wavelengths can be respectively regulated by one of the variable optical apparatuses.

Abstract: A trailing pole-tip for an electromagnetic transducer is formed as a layer oriented substantially perpendicular to other layers of the transducer, allowing the pole-tip to be made much thinner than conventional pole-tips. The novel pole-tip is formed on an edge or sidewall of a base layer instead of being formed on top of an existing layer. Potential errors in pole-tip thickness are much less than standard error tolerances for conventional pole-tip thickness. Having a greatly reduced pole-tip width significantly reduces the track width so that many more tracks can fit on a media surface, providing a large increase in areal density.

Abstract: A method of forming a head comprises forming a write transducer on a wafer, cutting the wafer to produce a slider bar with a cut surface, and planarizing the cut surface of the slider bar. Forming the write transducer can include forming a first pole layer and forming a first pole pedestal layer over the first pole layer, where the first pole pedestal layer includes a tapered portion defined by a first end having a nose width less than a desired final nose width, and a second end having a zero throat width greater than the desired final nose width. Planarizing the cut surface of the slider bar exposes the first pole pedestal layer until a width thereof approximately equals the desired final nose width.