Magnetic Information Storage Element Testing Patents (Class 324/210)
  • Patent number: 8461834
    Abstract: A magneto-impedance sensor element is formed in a planar type structure in which an amorphous wire is incorporated in a substrate. The magneto-impedance sensor element includes a nonmagnetic substrate, an amorphous wire arranged in an aligning direction of a planar pattern that forms a detecting coil, a spiral detecting coil formed of a planar pattern and a cubic pattern on an outer periphery of the amorphous wire, a planar insulating portion that insulates the planar pattern from the amorphous wire, a wire fixing portion to fix the amorphous wire on an upper surface of the planar insulating portion, and a cubic insulating portion that insulates the cubic pattern from the amorphous wire.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: June 11, 2013
    Assignee: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Michiharu Yamamoto, Katsuhiko Nishihata
  • Patent number: 8432631
    Abstract: A disk spindle assembly cartridge is described. The disk spindle assembly cartridge includes a base, a spindle motor attached to the base, a disk seated on the spindle motor, a disk clamp attached to the spindle motor, wherein the disk clamp secures the disk to the spindle motor, and a cover attached to the base. The base is configured to detachably mount a head stack assembly cartridge, where the disk is accessible to a head stack assembly pivotally mounted in the head stack assembly cartridge via an opening defined by the base and the cover.
    Type: Grant
    Filed: June 7, 2012
    Date of Patent: April 30, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Tao Lin, Chih-Wu Jen, Chunjer C. Cheng, Gang H. Lin
  • Patent number: 8368390
    Abstract: A well (2) doped for a conductivity type and provided as the sensor region is formed in a substrate (1) made of semiconductor material. Contact regions (4), arranged spaced apart from one another and doped for the same conductivity type as the well (2), are formed in a cover layer (3) that delimits the region with the conductivity type of the well. The contact areas (4) are electroconductively connected to the well (2) and provided for terminal contacts (6).
    Type: Grant
    Filed: August 26, 2010
    Date of Patent: February 5, 2013
    Assignee: Austriamicrosystems AG
    Inventors: Martin Schrems, Sara Carniello
  • Patent number: 8358127
    Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an SIN ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.
    Type: Grant
    Filed: April 7, 2010
    Date of Patent: January 22, 2013
    Assignee: TDK Corporation
    Inventors: Isamu Sato, Hiroshi Ikeda, Mikio Matsuzaki, Tetsuya Roppongi, Noboru Yamanaka, Tsutomu Aoyama
  • Patent number: 8332695
    Abstract: A data storage device (DSD) tester for testing a DSD is disclosed. The DSD tester comprises a plurality of bays, a screen, and control circuitry operable to detect when a first DSD has been inserted into a first bay. Independent of operator input, a graphical user interface (GUI) displayed on the screen is automatically updated to reflect the first DSD has been inserted into the first bay. Independent of operator input, a DSD test is automatically executed on the first DSD. When the first DSD is removed from the first bay, independent of operator input, the GUI is automatically updated to reflect the first DSD has been removed from the first bay.
    Type: Grant
    Filed: March 29, 2010
    Date of Patent: December 11, 2012
    Assignee: Western Digital Technologies, Inc.
    Inventors: Lawrence J. Dalphy, Daniel K. Blackburn
  • Publication number: 20120274317
    Abstract: A method of testing anti-high temperature performance of a magnetic head comprises applying a second magnetic field with different intensities in a second direction and the changing first magnetic fields in a first direction, and measuring a plurality of second output parameter curves; and judging whether a variation that is beyond an allowable value is presented on the second output parameter curves, thereby screening out a defective magnetic head, therein the first direction is perpendicular to the air bearing surface of the magnetic head, and the second direction is perpendicular to the shielding layers of the magnetic head. The present invention can screen out defective magnetic heads that possess poor anti-high temperature performance without heating the magnetic head and with high precision.
    Type: Application
    Filed: April 29, 2011
    Publication date: November 1, 2012
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Chiuming Lueng, Cheukman Lui, Mankit Lee, Hokei Lam, Kwokkam Leung, Cheukwing Leung, Juren Ding, Rongkwang Ni
  • Patent number: 8299784
    Abstract: A device for transporting a magnetic head, a device for inspecting a magnetic head, and a method for manufacturing a magnetic head are provided. The device for transporting a magnetic head is capable of freely changing a posture of a thin film magnetic head when transporting a row bar-shaped thin film magnetic head. The transporting device for transporting a slender rectangular plate-like, that is, row bar-shaped magnetic head, cut from a wafer is capable of performing vertical installation and horizontal installation. The transporting device for transporting a slender rectangular plate-like, i.e., row bar-shaped magnetic head, is capable of performing the vertical installation and horizontal installation, and changing the posture of the magnetic head from vertical installation into horizontal installation and from horizontal installation into vertical installation when transporting the magnetic head between processes.
    Type: Grant
    Filed: June 21, 2010
    Date of Patent: October 30, 2012
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Teruaki Tokutomi, Akira Tobita, Tsuneo Nakagomi
  • Patent number: 8289015
    Abstract: The application relates to utilizing a head assembly, having a default boot-up head and at least one other head, in a depopulated configuration. If, during testing of the head assembly, the default boot-up head is found to be flawed, it designated as faulty in a non-volatile memory in the head assembly. The head assembly with the default boot-up head is used in a data storage device.
    Type: Grant
    Filed: April 14, 2008
    Date of Patent: October 16, 2012
    Assignee: Seagate Technology LLC
    Inventor: Hossein F. Sevvom
  • Publication number: 20120249130
    Abstract: A method for measuring longitudinal bias magnetic field in a tunnel magnetoresistive sensor of a magnetic head, the method includes the steps of: applying an external longitudinal time-changing magnetic field onto the tunnel magnetoresistive sensor; determining a shield saturation value of the tunnel magnetoresistive sensor under the application of the external longitudinal time-changing magnetic field; applying an external transverse time-changing magnetic field and an external longitudinal DC magnetic field onto the tunnel magnetoresistive sensor; determining a plurality of different output amplitudes under the application of the external transverse time-changing magnetic field and the application of different field strength values of the external longitudinal DC magnetic field; plotting a graph according to the different output amplitudes and the different field strength values; and determining the strength of the longitudinal bias magnetic field according to the graph and the shield saturation value.
    Type: Application
    Filed: July 1, 2011
    Publication date: October 4, 2012
    Applicant: SAE Magnetics (H.K.) Ltd.
    Inventors: Siuman MOK, Hokei LAM, Cheukwing LEUNG, Juren DING, Rongkwang NI, Wanyin KWAN, Cheukman LUI, Chiuming LUENG
  • Patent number: 8278917
    Abstract: A magnetic head inspection device inspects the write track width of a thin film magnetic head in a phase as early as possible during the manufacturing process. A recording signal (excitation signal) is input from bonding pads to the thin film magnetic head in a rowbar, and the magnetic field generated by the write pole (element) included in the thin film magnetic head is observed directly by using a magnetic force microscope (MFM), a scanning Hall probe microscope (SHPM), or a scanning magneto resistance effect microscope (SMRM) that performs a scanning motion at a position equivalent to the flying height of the magnetic head. In this manner, a shape of the generated magnetic field instead of the physical shape of the write pole (element) is measured; thus, a non-destructive inspection can be performed on the effective magnetic track width.
    Type: Grant
    Filed: February 27, 2009
    Date of Patent: October 2, 2012
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Tsuneo Nakagomi, Teruaki Tokutomi
  • Patent number: 8274277
    Abstract: A high-resolution magnetic encoder system includes a magnetic resistive sensor, a fixed suspension, and a mechanism. The magnetic resistive sensor is mounted to the fixed suspension above a magnetic medium having at least one magnetic track. The fixed suspension is attached to the mechanism, such as a housing, a substrate, and/or an electronic board. The sensor is adapted to perform a relative movement with respect to and in close contact to the surface of the magnetic medium. The magnetic medium may be protected by an overcoat layer. The magnetic resistive sensor may be Giant Magnetic-Resistive (GMR) sensor and/or a Tunneling Magnetic-Resistive Sensor (TMR).
    Type: Grant
    Filed: August 29, 2009
    Date of Patent: September 25, 2012
    Assignee: International Business Machines Corporation
    Inventors: Andreas Dietzel, Marcus Breuer, Hubert Grimm, Karl-Heinz Lehnhert, Nikolaus Luckner, Rolf Schaefer, Guenther Michaelis
  • Patent number: 8218256
    Abstract: A disk spindle assembly cartridge is described. The disk spindle assembly cartridge includes a base, a spindle motor attached to the base, a disk seated on the spindle motor, a disk clamp attached to the spindle motor, wherein the disk clamp secures the disk to the spindle motor, and a cover attached to the base. The base is configured to detachably mount a head stack assembly cartridge, where the disk is accessible to a head stack assembly pivotally mounted in the head stack assembly cartridge via an opening defined by the base and the cover.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: July 10, 2012
    Assignee: Western Digital Technologies, Inc.
    Inventors: Tao Lin, Chih-Wu Jen, Chunjer Chuck Cheng, Gang Herbert Lin
  • Patent number: 8219858
    Abstract: A method for testing hard disks under an extensible firmware interface (EFI) provides a device tree of hard disks. Nodes of the device tree represent block devices or file systems of the hard disks. Devices paths and handles corresponding to each of the device paths are obtained from the device tree. Parent controller handles of each of the device paths are obtained. If there are parent controller handles the same as the obtained handles, the parent controller handles the same as the obtained handles are deleted. The computer determines that a number of the hard disks is equal to a number of the device paths corresponding to the remained parent controller handles. Nodes information of each of the device paths corresponding to the remained parent controller handles are determined as hard disk information of each of the hard disks.
    Type: Grant
    Filed: December 31, 2009
    Date of Patent: July 10, 2012
    Assignees: Hong Fu Jin Precision Industry (ShenZhen) Co., Ltd., Hon Hai Precision Industry Co., Ltd.
    Inventor: Ge-Xin Zeng
  • Patent number: 8214718
    Abstract: A system and method for erasure flagging for errors-and-erasures decoding in storage devices includes determining a deviation measure between a read/write head position relative to a track of symbols in storage media. A reliability value is determined for the symbols based on the deviation measure. Flagging the symbols with a reliability value below a threshold as erasures is performed. The symbols are decoded using errors-and-erasures decoding in an iterative procedure.
    Type: Grant
    Filed: June 19, 2008
    Date of Patent: July 3, 2012
    Assignee: International Business Machines Corporation
    Inventors: Theodore A. Antonakopoulos, Charalampos Pozidis, Maria Varsamou
  • Publication number: 20120146631
    Abstract: A test apparatus can test a read head and/or a disk. The test apparatus includes a rotatable spindle adapted to hold the disk, and a holder oriented to hold the read head with its air bearing surface adjacent the major surface of the disk during testing. The holder includes a channel with a first side wall. The channel defines a channel longitudinal axis parallel to the first side wall. The channel also defines a lateral direction that is normal to the first side wall. A first gas jet points into the channel and impinges upon a top face of the read head.
    Type: Application
    Filed: December 14, 2010
    Publication date: June 14, 2012
    Applicant: MICROPHYSICS INC.
    Inventor: Christopher Allen Lacey
  • Patent number: 8179134
    Abstract: An upward warp of a terminal pad of a flexible cable which is kept horizontal by a suction head is prevented by a pressing arm which contacts with an upper surface of a rear portion of the flexible cable.
    Type: Grant
    Filed: June 24, 2009
    Date of Patent: May 15, 2012
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Toshinori Sugiyama, Shinji Honma, Yoshinori Tokumura, Hideki Mochizuki
  • Publication number: 20120077060
    Abstract: An evaluation method that can easily evaluate properties of a carbon protective film and a lubricant on a magnetic-disk surface or particularly, an evaluation method of a magnetic disk in which the properties of the magnetic-disk surface can be evaluated accurately so that a strict demand for interactions between the magnetic-disk surface and a head can be met is provided. In a state in which an element portion of the magnetic head provided with the head element portion that projects by thermal expansion is projected, after being brought into contact with a predetermined radial position on the surface of the rotating magnetic disk, the head is further made to perform seeking in a state in which the element portion is projected by a specified amount, whereby the properties of the carbon film or the lubricant formed on the magnetic-disk surface is evaluated.
    Type: Application
    Filed: March 29, 2011
    Publication date: March 29, 2012
    Applicant: WD Media (Singapore) Pte. Ltd.
    Inventor: Tsuyoshi Ozawa
  • Patent number: 8138754
    Abstract: The characteristics of thin-film magnetic heads are evaluated by measuring, in a step and repeat method and apparatus, the magnetic field generated by the respective heads in a bar including multiple heads.
    Type: Grant
    Filed: May 18, 2009
    Date of Patent: March 20, 2012
    Assignee: TDK Corporation
    Inventors: Akio Ogawa, Tsutomu Chikamatsu, Kazuyuki Kobayashi, Haruhiko Yamaguchi, Kazunori Matsuiwa, Masaki Ohashi, Kazuyoshi Nakajima, Kiyotaka Shindo
  • Publication number: 20120056619
    Abstract: A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field.
    Type: Application
    Filed: November 16, 2011
    Publication date: March 8, 2012
    Applicant: Infinitum Solutions, Inc.
    Inventor: Alexander M. Taratorin
  • Publication number: 20120056618
    Abstract: A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field.
    Type: Application
    Filed: November 15, 2011
    Publication date: March 8, 2012
    Applicant: Infinitum Solutions, Inc.
    Inventor: Alexander M. Taratorin
  • Patent number: 8120353
    Abstract: A method for detecting a damaged magnetoresistive sensor in one embodiment includes measuring a resistance of a first sensor upon application thereto of a positive bias current; measuring the resistance of the first sensor upon application thereto of a negative bias current; determining a difference in the measured resistances at positive and negative currents of the first sensor; measuring a resistance of a second sensor upon application thereto of a positive bias current; measuring the resistance of the second sensor upon application thereto of a negative bias current; determining a difference in the measured resistances at positive and negative currents of the second sensor; and outputting at least one of the differences, or a derivative of the at least one of the differences. Additional methods are also presented.
    Type: Grant
    Filed: April 28, 2008
    Date of Patent: February 21, 2012
    Assignee: International Business Machines Corporation
    Inventor: Icko E. Tim Iben
  • Patent number: 8106650
    Abstract: A position-sensing system includes a first component (e.g., a cylinder) and a second component (e.g., a piston rod) movably coupled to the first component for movement with respect thereto. A magnetically hard layer on the second component provides a recording medium. Regions of the magnetically hard layer are magnetized as magnetized rings around the second component. Magnetic-field sensors are coupled to the first component in proximity of the magnetically hard layer on the second component to sense the rings of magnetized regions. Each of the magnetic field sensors senses flux from each of the rings of magnetized regions as the second component is moving with respect to the first component and, in response to sensing the rings of magnetized regions, generates signals used to determine position of the second component.
    Type: Grant
    Filed: November 24, 2010
    Date of Patent: January 31, 2012
    Assignee: SRI International
    Inventors: Donald C. Arns, Pablo Garcia
  • Patent number: 8102173
    Abstract: A disk drive test slot thermal control system includes a test slot including a housing having an outer surface, an internal cavity defined by the housing and including a test compartment for receiving and supporting a disk drive transporter carrying a disk drive for testing, and an inlet aperture extending from the outer surface of the housing to the internal cavity. The disk drive test slot thermal control system also includes a cooling conduit, and a thermoelectric device mounted to the cooling conduit. The thermoelectric device is configured to cool or heat an air flow entering the internal cavity through the inlet aperture.
    Type: Grant
    Filed: April 17, 2008
    Date of Patent: January 24, 2012
    Assignee: Teradyne, Inc.
    Inventor: Brian S. Merrow
  • Patent number: 8099852
    Abstract: A method for assembling an image capturing device is provided. The image capturing device includes a light-pervious module, an image sensor and a binding material. The image sensor has a light sensing region for converting an imaging light into an electronic signal. The binding material is used for binding articles together and curable by a curing process. Firstly, the light-pervious module and the image sensor together are releasably bound together via the binding material, thereby defining a close space for accommodating the image sensor. Then, a testing process is performed to detect a clean condition of the close space. If particles present in the close space are detected, the light-pervious module is detached from the image sensor, a cleaning process is done to remove the particle, and the light-pervious module and the image sensor are releasably bound together to define the close space again. Afterwards, the binding material is cured.
    Type: Grant
    Filed: March 6, 2009
    Date of Patent: January 24, 2012
    Assignee: Primax Electronics Ltd.
    Inventor: Jui-Hsiang Lo
  • Patent number: 8085038
    Abstract: A noise-testing method for a thin-film magnetic head with an MR read head element and a heating unit capable of applying a heat and a stress to the MR read head element, includes a step of applying alternately and discontinuously with each other an electrical power having a first level and an electrical power having a second level higher than the first level to the heating unit, and a step of evaluating the thin-film magnetic head by measuring a noise output or noise outputs obtained from the MR read head element when the electrical power or the electrical powers are applied to the heating unit.
    Type: Grant
    Filed: May 25, 2007
    Date of Patent: December 27, 2011
    Assignees: TDK Corporation, SAE Magnectics (H.K.) Ltd.
    Inventors: Takumi Uesugi, Takeo Kagami, Tetsuro Sasaki, Kei Hirata, Masaru Hirose, Chi Man Lee, Kwok Piu Tso
  • Patent number: 8080992
    Abstract: A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field.
    Type: Grant
    Filed: November 15, 2007
    Date of Patent: December 20, 2011
    Assignee: Infinitum Solutions, Inc.
    Inventor: Alexander M. Taratorin
  • Patent number: 8072231
    Abstract: A testing method of a wafer provided with a plurality of thin-film magnetic heads is provided. Each of the plurality of thin-film magnetic heads includes a main pole layer, a first test pad formed on the wafer and electrically connected with an extended top end section of the main pole layer and a second test pad formed on the wafer and electrically connected with a back end section of the main pole layer. The testing method includes a step of measuring an electrical resistance between the first test pad and the second test pad, a step of judging whether the measured electrical resistance is within a set range, and a step of discriminating that the thin-film magnetic head is a non-defective product when the measured electrical resistance is within the set range.
    Type: Grant
    Filed: May 28, 2009
    Date of Patent: December 6, 2011
    Assignee: TDK Corporation
    Inventors: Isamu Toba, Yasuhiro Hasegawa, Koichi Otani, Takamitsu Sakamoto
  • Patent number: 8063630
    Abstract: In testing thin-film magnetic heads, first, a back surface opposite to a medium facing surface of each of a plurality of thin-film magnetic heads is attached to a first surface of a first plate of a jig, the jig including the first plate of rubber having the first and second surfaces facing toward opposite directions, and a second plate greater in rigidity than the first plate and bonded to the second surface of the first plate. Next, the plurality of thin-film magnetic heads and the jig are mounted on a metal plate having a flat top surface, such that the medium facing surfaces of the thin-film magnetic heads touch the top surface of the metal plate. Next, heat-generating components of the plurality of thin-film magnetic heads mounted on the metal plate are energized.
    Type: Grant
    Filed: March 14, 2008
    Date of Patent: November 22, 2011
    Assignee: TDK Corporation
    Inventors: Takamitsu Kamimura, Masato Sugahara, Kenji Yumoto
  • Patent number: 8040131
    Abstract: A method for testing a magnetic head to determine whether the magnetic head is unacceptably affected by temperature variations. The test includes testing the magnetic head at different temperatures and measuring either or both of a signal amplitude and a signal asymmetry of a signal from the magnetic head at the different temperatures. If signal amplitude or signal asymmetry vary excessively as a result of the temperature change then the head can be scrapped.
    Type: Grant
    Filed: July 1, 2008
    Date of Patent: October 18, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David Ernest Call, Ciaran Avram Fox, Jih-Shiuan Luo, Robert Langland Smith, Chin-Yu Yeh
  • Patent number: 8018226
    Abstract: In one embodiment, a method for detecting a damaged magnetoresistive sensor includes analyzing readback signals of a plurality of sensors each being positioned over data tracks on a passing magnetic medium; determining whether at least one of the readback signals is out of phase with respect to the other readback signals, and/or whether at least one of the readback signals has a significantly lower amplitude that the other readback signals. Additional methods are also presented.
    Type: Grant
    Filed: April 28, 2008
    Date of Patent: September 13, 2011
    Assignee: International Business Machines Corporation
    Inventors: Icko E. Tim Iben, Darrell G. Follett, Guillermo Paniagua
  • Patent number: 8008912
    Abstract: A method of testing P2 stiffness of a magnetoresistance (MR) sensor stack including a P2 pinned layer is provided. The method comprises the step of applying an external magnetic field to the MR sensor stack. The external magnetic field is oriented substantially perpendicular to a magnetic field of the P2 pinned layer. The method further comprises varying an amplitude of the external magnetic field, measuring a change in a resistance of the MR sensor stack in response to the varying amplitude of the external magnetic field, and calculating the P2 stiffness based on the measured change in resistance.
    Type: Grant
    Filed: December 16, 2008
    Date of Patent: August 30, 2011
    Assignee: Western Digital (Fremont), LLC
    Inventor: Changhe Shang
  • Patent number: 7987583
    Abstract: A step portion for mounting a row bar is provided at a table stepping down from the face of the table, and by lowering a pair of hooks crossing over the step portion in its width direction, a row bar held by the hooks is mounted on the step portion. While interposing the row bar mounted on the step portion between a pair of hooks and a side face of the step portion, the side in longitudinal direction of the row bar and the bottom face thereof are butted to the bottom face and the standing up side face of the step portion to position two axes of the row bar among XYZ directions, successively, positioning of the row bar in one remaining direction along longitudinal direction of the row bar mounted on the step portion is performed by moving the table in the one remaining axial direction.
    Type: Grant
    Filed: March 20, 2008
    Date of Patent: August 2, 2011
    Assignee: Hitachi High-Technologies Corporation
    Inventors: Teruaki Tokutomi, Yoshinori Kitano
  • Patent number: 7990137
    Abstract: An MR element having a magnetically free layer and a magnetic bias layer that applies a bias magnetic field to the magnetically free layer are included. Furthermore, a measuring section that measures a ferromagnetic resonance frequency f0 of the magnetically free layer under a condition of applying a predetermined external magnetic field Hm to the magnetically free layer, and an operation section that computes the bias magnetic field Hb according to a following conditional expression (1): Hb={(2*?*f0/?)2/Ms}?(Hk+Hm)??(1) where ? is a gyroscope constant, Ms is a saturation magnetic field of the magnetically free layer, and Hk is a shape anisotropy magnetic field of the magnetically free layer.
    Type: Grant
    Filed: March 30, 2009
    Date of Patent: August 2, 2011
    Assignee: TDK Corporation
    Inventor: Yosuke Antoku
  • Patent number: 7960968
    Abstract: It is an object of the present invention to provide a method for investigating magnetic domains, the method capable of easily grasping behavior of the magnetic domains in a head manufacturing process, and further to provide a testing method of a magnetic head capable of evaluating whether the writing performance of the magnetic head is good or not. The method for investigating magnetic domains comprises supplying direct current (DC) to a coil of an electromagnetic transducer provided in a magnetic head for writing data onto a magnetic recording medium; measuring an inductance of the electromagnetic transducer at each current value while varying the current value of the direct current; and investigating behavior of magnetic domains in a magnetic core of the electromagnetic transducer based on a relationship between the current values and the inductances.
    Type: Grant
    Filed: April 14, 2008
    Date of Patent: June 14, 2011
    Assignee: TDK Corporation
    Inventors: Hiroshi Kiyono, Takahiro Mori
  • Publication number: 20110116303
    Abstract: A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current.
    Type: Application
    Filed: January 24, 2011
    Publication date: May 19, 2011
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Yiran Chen, Alan Wang, Haiwen Xi, Wenzhong Zhu, Hai Li, Hongyue Liu
  • Patent number: 7940042
    Abstract: A method for testing an MR element includes a step of obtaining a ferromagnetic resonance frequency f0 of the MR element to be tested by applying an external magnetic field in a track-width direction to the MR element, a step of calculating a stiffness magnetic field Hstiff from the obtained ferromagnetic resonance frequency f0 using a predetermined formula, a step of obtaining a relationship of a stiffness magnetic field Hstiff with respect to an external magnetic field applied in the track-width direction from the applied external magnetic field and the calculated stiffness magnetic field Hstiff, a step of obtaining a uniaxial anisotropic magnetic field Hk of a free layer of the MR element from the obtained relationship of the stiffness magnetic field Hstiff with respect to the external magnetic field applied, and a step of judging whether the MR element is good product or not by comparing the obtained uniaxial anisotropic magnetic field Hk with a predetermined threshold.
    Type: Grant
    Filed: January 7, 2009
    Date of Patent: May 10, 2011
    Assignee: TDK Corporation
    Inventor: Takumi Yanagisawa
  • Publication number: 20110101990
    Abstract: An age compensation method and apparatus for an integrated circuit (IC). An IC may be configured to operate at an initial operating voltage at the beginning of its operational life. Various circuits may be used to detect aging of the IC, and indications of aging may be stored to determine the aging of the IC. The information indicative of the determined aging of the IC may be compared to an aging threshold. If the information indicates that the aging is greater than or equal to the determined aging threshold, the operating voltage of the IC may be increased. This process may be repeated over the life of the IC, increasing the operating voltage as the IC ages. Raising the operating voltage in response to aging may compensate for various age related degradation mechanisms that can occur over the operational life of the IC.
    Type: Application
    Filed: October 30, 2009
    Publication date: May 5, 2011
    Inventors: Date Jan Willem Noorlag, Michael Frank
  • Patent number: 7932717
    Abstract: Test methods and components are disclosed for testing resistances of magnetoresistance (MR) sensors in read elements. Test components are fabricated on a wafer with a first test lead, a pseudo sensor, and a second test lead. The test leads and MR sensor are fabricated with similar processes as first shields, MR sensors, and second shields of read elements on the wafer. However, the pseudo sensor in the test component is fabricated with lead material (or another material having similar resistance properties) instead of an MR thin-film structure like an MR sensor. Forming the pseudo sensor from lead material causes the resistance of the pseudo sensor to be insignificant compared to the lead resistance. Thus, a resistance measurement of the test component represents the lead resistance of a read element. An accurate resistance measurement of an MR sensor in a read element may then be determined by subtracting the lead resistance.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: April 26, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Robert S. Beach, Mary K. Gutberlet, David J. Seagle
  • Patent number: 7928743
    Abstract: A measuring bridge arrangement has a measuring bridge with a first supply terminal and first and second measuring signal terminals. The measuring bridge arrangement has a working point adjustment circuit formed to feed the measuring bridge via at least the first supply terminal in a measuring state of operation, and to apply a signal to one of the measuring signal terminals in the test state of operation in order to bring the measuring bridge to a test working point different from a measuring working point in the measuring state of operation. The measuring bridge has a test tap, wherein a test signal dependent on resistive properties of at least one element of the measuring bridge can be tapped at the test tap of the measuring bridge.
    Type: Grant
    Filed: May 30, 2008
    Date of Patent: April 19, 2011
    Assignee: Infineon Technologies AG
    Inventor: Udo Ausserlechner
  • Patent number: 7911740
    Abstract: Apparatus for receiving and positioning a read/write head to a disk in a test apparatus has a deck and a spindle on the deck and on which a disk can be mounted for rotation of the disk. A gripper is provided for holding a head during testing, the gripper being movable over a surface of the deck. A precisor receives a head and accurately aligns the head, the precisor being movable over a surface of the deck. A pick is operable to pick up and place down a head. The precisor is movable to a position where the pick can pick up a head from the precisor and place down a head on the precisor. The gripper is movable to a position where the pick can pick up a head from the gripper and place down a head on the gripper.
    Type: Grant
    Filed: September 8, 2006
    Date of Patent: March 22, 2011
    Assignees: Xyratex Technology Limited, Seagate Technology LLC
    Inventor: Ian Stanley Warn
  • Publication number: 20110057649
    Abstract: In the present invention, to make corrective matching thereof, it is designed as follows; position effect of defects coordinates, which are output from an inspection apparatus, is allowed, coordinates of inspected data are mutually corrected, and a state of coincidence or non-coincidence among a plurality sets of inspected data is output or displayed. Inspection data is designed to include kinds, kinds difference and dimension of defects. A state of coincidence or non-coincidence between inspected data is designed to be output or displayed appropriately, by kinds or dimensions, or by a grouping thereof, of a defects object. The same sample is inspected by every time of passing a production step, and a state of data increase or decrease, or coincidence or non-coincidence between the inspected data is designed to be output or displayed.
    Type: Application
    Filed: November 15, 2010
    Publication date: March 10, 2011
    Inventors: Minoru YOSHIDA, Shunji Maeda
  • Patent number: 7891080
    Abstract: A method for detecting head-disc contact is disclosed. The method comprises locating a head including a head positioning microactuator and at least one of a read transducer and a write transducer adjacent to a disc such that the head is in communication with the disc, monitoring an output signal from the head positioning microactuator of the head, and evaluating the output signal to determine if the head contacts the disc.
    Type: Grant
    Filed: November 6, 2007
    Date of Patent: February 22, 2011
    Assignee: Seagate Technology LLC
    Inventors: James C. Alexander, Jason H. Laks
  • Patent number: 7872471
    Abstract: Provided is a method for testing a head element that enables proper evaluation of the head element based on a characteristic of the head element under high-temperature and high-stress conditions. The testing method can be performed on a thin-film magnetic head including a head element and a heating element capable of applying a heat and stress to the head element, or performed on a row bar or a substrate wafer on which a plurality of the head elements and a plurality of the heating elements are disposed. The testing method comprises the steps of: causing the heating element to generate heat to apply a heat and stress to the head element; and measuring a characteristic of the head element under the heat and stress to evaluate the head element.
    Type: Grant
    Filed: August 7, 2007
    Date of Patent: January 18, 2011
    Assignees: TDK Corporation, SAE Magnetics (H.K.) Ltd.
    Inventors: Noboru Yamanaka, Soji Koide, Yoshiyuki Mizoguchi, Eric Cheuk Wing Leung, Chris Chiu Ming Leung, Leo Wai Kay Lau, Charles Kin Chiu Wong
  • Patent number: 7855553
    Abstract: Test methods and components are disclosed for testing resistances of magnetoresistance (MR) sensors in read elements. Test components are fabricated on a wafer with a first test lead, a test MR sensor, and a second test lead. The test leads and test MR sensor are fabricated with similar processes as first shields, MR sensors, and second shields of read elements on tie wafer. However, the test MR sensor is fabricated with an area that is larger than areas of the MR sensors in the read elements. The larger area of the test MR sensor causes the resistance of the test MR sensor to be insignificant compared to the lead resistance. Thus, a resistance measurement of the test component represents the lead resistance of a read element. An accurate resistance measurement of an MR sensor in a read element may then be determined by subtracting the lead resistance.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: December 21, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Robert S. Beach, Mary K. Gutberlet, David J. Seagle
  • Patent number: 7852072
    Abstract: A test-device system and method for deconvoluting measurements of effects of a sensor-width definition process from measurements of effects of a sensor-stripe-height-definition process in a manufacture of a magnetic sensor. The test-device system comprises a first test device for generating data to characterize a sensor-width-definition process. The test-device system also comprises a second test device for generating data to characterize a sensor-stripe-height-definition process. The test-device system allows independent characterization of a sensor-width parameter and a sensor-stripe-height parameter.
    Type: Grant
    Filed: December 31, 2007
    Date of Patent: December 14, 2010
    Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.
    Inventors: Satoru Araki, Robert S. Beach, Ying Hong, David J. Seagle
  • Patent number: 7729107
    Abstract: A disk drive test apparatus has a plurality of bays each for receiving a respective disk drive to be tested. A plurality of card slots are provided each for receiving a test card via which a disk drive can be tested. Each of the test cards is either an environment test card or an interface test card. The card slots and the test cards are arranged such that each card slot (6) can selectively receive an environment test card or an interface test card. Other arrangements for disk drive test apparatus or disk drive mounting apparatus are disclosed.
    Type: Grant
    Filed: September 9, 2005
    Date of Patent: June 1, 2010
    Assignee: Xyratex Technology Limited
    Inventors: Andrew William Atkins, Steve Andrew Bailey, David Ronald Bain Farquhar, David John Orriss, Kevin Richardson
  • Patent number: 7729072
    Abstract: A storage drive implements a method for operating the storage drive between a plurality of operational modes. For a test mode of the storage drive, a write current driver circuit and a test current sensor are electrically connected to the write head, wherein the test current sensor generates a sense signal indicative of a degree of a flow of a test current through the write head to thereby facilitate a detection of any presence of an open write condition of the storage drive (i.e., any impedance condition impeding a flow of a write current through the write head). For a write mode of the storage drive, the write current driver circuit is electrically connected to the write head and the test current sensor is electrically disconnected from the write head, wherein the write head records data on a magnetic media based on a flow of the write current through the write head.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: June 1, 2010
    Assignee: International Business Machines Corporation
    Inventors: Jacob L. Dahle, Larry L. Tretter
  • Patent number: 7723982
    Abstract: A magnetic head suffers mechanical stresses by striking against a magnetic disc surface and dust, so that there are problems such as the reduction of reproduction output due to the mechanical stresses and the reversal of output polarity due to the mechanical stresses. Embodiments in accordance with the present invention relate to a method of testing reliability of reproduction elements of a magnetic head against outside stress. In a first step, a Giant Magnetoresistive (GMR) element on a row bar of the object of inspection, or a GMR element on a slider is measured for the output against external magnetic field. In the next step, prescribed shearing stress is applied with indenter to the edge where the GMR element-formed surface of the row bar or slider and the air-bearing surface are crossed. Then, output of the GMR element is measured again. Lastly, the outputs of the GMR element before and after application of stress are compared.
    Type: Grant
    Filed: January 19, 2007
    Date of Patent: May 25, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Shinji Sasaki, Makoto Torigoe, Takayoshi Ohtsu, Kouji Kataoka
  • Publication number: 20100109656
    Abstract: A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current.
    Type: Application
    Filed: February 9, 2009
    Publication date: May 6, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Yiran Chen, Alan Wang, Haiwen Xi, Wenzhong Zhu, Hai Li, Hongyue Liu
  • Patent number: 7705588
    Abstract: An apparatus and method for testing a component of a magnetic disk drive in which one or more drive-based components is used in the testing process. Each of the drive-based components is based on a corresponding one of the components of the magnetic disk drive. During testing, the component to be tested and at least one of the drive-based components are selectively engaged.
    Type: Grant
    Filed: October 5, 2005
    Date of Patent: April 27, 2010
    Assignee: Seagate Technology LLC
    Inventors: Robert Eaton, Gang Herbert Lin, Tao Lin, Amir Ali Companieh, Rob Milby, Ron Carroll, Robert Kimball