| 序号 | 专利名 | 申请号 | 申请日 | 公开（公告）号 | 公开（公告）日 | 发明人 |
|---|---|---|---|---|---|---|
| 181 | Disk drive and magnetic head for perpendicular magnetic recording | US10769477 | 2004-01-29 | US20040228031A1 | 2004-11-18 | Akihiko Takeo |
| A magnetic head is operable for recording in a perpendicular magnetic recording manner and has a recording pole portion which has a soft magnetic film and which generates a recording magnetic flux in a vertical direction of the perpendicular magnetic recording medium and in which the recording pole portion includes a hard magnetic film to steadily apply a static field and an exchange-coupling field having the same polarity to the soft magnetic film of the recording pole portion in a direction of a track width. The recording pole portion may also have a non-magnetic layer inserted between a soft magnetic film and a hard magnetic film. | ||||||
| 182 | Composite write pole for a magnetic recording head | US09683187 | 2001-11-29 | US06721131B2 | 2004-04-13 | Dmitri Litvinov; Sakhrat Khizroev; Billy Wayne Crue |
| A main write pole for a perpendicular recording head for use with magnetic recording media includes a main body portion of a material with a low magnetic moments, a trailing edge of a material having a high magnetic moment and a non-magnetic de-coupling layer therebetween. The strong magnetic recording field generated by the high moment magnetic material permits the use of a magnetic recording media having high anisotropy, thereby reducing super paramagnetic instabilities at high recording densities. Additionally, the high magnetic moment of the trailing edge, combined with the low magnetic moments of the remainder of the write pole, results in a highly localized magnetic recording field, thereby reducing the sensitivity of the recording process to the skew angle. Further, the de-coupling between the low and high magnetic moment portions of the write pole minimize the problem of magnetic remanence. | ||||||
| 183 | Magnetic head and magnetic storage apparatus | US10354989 | 2003-01-31 | US20040037002A1 | 2004-02-26 | Kazue Kudo; Yoshiaki Kawato; Kazuhiro Nakamoto; Nobuo Yoshida; Kimitoshi Etoh |
| Disclosed herein is a magnetic head for perpendicular recording in which the main magnetic pole has reduced remanent magnetization and is less liable to cause erasure after recording. These characteristic properties were realized by constructing the magnetic head such that the recording magnetic pole and the yoke are separate from each other and the main magnetic pole is formed from a material with a high saturation magnetic flux density and the yoke is formed from a material having a negative magnetostriction constant. | ||||||
| 184 | Composite write pole for a magnetic recording head | US09683187 | 2001-11-29 | US20020131203A1 | 2002-09-19 | Dmitri Litvinov; Sakhrat Khizroev; Billy Wayne Crue |
| A main write pole for a perpendicular recording head for use with magnetic recording media includes a main body portion of a material with a low magnetic moments, a trailing edge of a material having a high magnetic moment and a non-magnetic de-coupling layer therebetween. The strong magnetic recording field generated by the high moment magnetic material permits the use of a magnetic recording media having high anisotropy, thereby reducing super paramagnetic instabilities at high recording densities. Additionally, the high magnetic moment of the trailing edge, combined with the low magnetic moments of the remainder of the write pole, results in a highly localized magnetic recording field, thereby reducing the sensitivity of the recording process to the skew angle. Further, the de-coupling between the low and high magnetic moment portions of the write pole minimize the problem of magnetic remanence. | ||||||
| 185 | READ HEAD WITH FILE RESETTABLE DUAL SPIN VALVE SENSOR | US09369076 | 1999-08-05 | US20020067577A1 | 2002-06-06 | ROBERT STANLEY BEACH; MATTHEW CAREY; BRUCE A. GURNEY |
| A dual spin valve sensor is provided which is file resettable. An antiparallel (AP) coupled free layer structure is located between first and second pinned layer structures. The AP coupled free layer structure includes an AP coupling layer between first and second AP coupled free layers. When a current pulse is conducted through a sense current circuit the temperature of the sensor increases and conductive layers of the spin valve sensor exert current fields on the first and second pinned structures which set the magnetic spins of first and second antiferromagnetic pinning layers exchange coupled thereto. When the current pulse is terminated or reduced and the sensor cools the first and second pinning layers pin the magnetic moments of the first and second pinned layers antiparallel with respect to each other. Since magnetic moments of the first and second AP coupled free layers are also antiparallel with respect to each other the magnetic moments of the AP coupled free layer structure and the pinned layers are in phase so that a magnetoresistance, one on each side of the AP coupled free layer structure, are additive to provide a dual magnetoresistive effect. | ||||||
| 186 | Method for eliminating wiggle of magnetic head in hard disk drive | US09261391 | 1999-03-03 | US06297925B1 | 2001-10-02 | Jae-sung Lee |
| A method for eliminating a wiggle of a magnetic head in a hard disk drive includes the steps of moving a first magnetic head to a parking area when wiggle is generated in the first magnetic head being in use, checking whether the first magnetic head is positioned in the parking area, using a second magnetic head at which the wiggle is not generated, and eliminating the wiggle by supplying current to the first magnetic head. The eliminating step further includes the step of supplying current to allow the first magnetic head to move to the parking area. | ||||||
| 187 | Methods for initializing and/or resetting GMR heads by applying oppositely directed magnetic fields | US09220808 | 1998-12-23 | US06275028B1 | 2001-08-14 | Takao Matsui; Tatsuya Endo; Hiroaki Suzuki; Kenji Kuroki; Katsushi Yamaguchi; Hideo Asano |
| In accordance with the present invention, the initialization for orienting the magnetized directions of the free layers of GMR heads (mounted on the diagonally shaded surface of sliders 14) by an external magnetic field is again executed also for the opposite direction, thereby to increase the yield of the GMR heads. Further, it is determined whether the magnetized direction of the pinned layer of GMR heads can be once reversed to the opposite direction, thereby to select damaged GMR heads at an early stage. Then, by performing a reset while performing a quasi-static test for seeing the read back response of the GMR head after restoring the magnetized direction of the pinned layer to a positive rotation, a safe and efficient reset is executed. The reset can be executed not only by applying only a pulse, but also while providing an external magnetic field in the pinning direction, or only by giving a high magnetic field. A tool 500 can be commonly used for the initialization, reset, or read back response through each process level. For the quasi-static test, coils 531, 532, and 533 are selectively used as Helmholz coils. | ||||||
| 188 | Method and apparatus for initializing a magnetoresistive head | US12055 | 1998-01-22 | US6028730A | 2000-02-22 | Kunihiko Ishihara |
| The present invention provides a device for supplying an initialization pulse current to at least laminations of a pinned ferromagnetic layer, a non-magnetic metal layer and a free ferromagnetic layer in a magnetoresistive transducer in an initialization pulse current direction which is perpendicular to a predetermined magnetization direction of the pinned ferromagnetic layer and also parallel to an interface between the pinned ferromagnetic layer and the non-magnetic metal layer, wherein the device is electrically connected to opposite ends of the laminations spaced from each other in the initialization current direction for applying a pulse voltage between the opposite ends so as to flow the initialization pulse current in the initialization pulse current direction through the laminations. | ||||||
| 189 | Preamplifier bias mode to re-initialize a GMR head after losing initialization | US970573 | 1997-11-14 | US5969523A | 1999-10-19 | Paul Wingshing Chung; John Thomas Contreras; Klaas Berend Klaassen; Calvin Shizuo Nomura |
| A method and apparatus for re-initializing a GMR head after losing initialization is disclosed. The invention may use a voltage controlled waveform, which allows the current to vary with the resistance of the GMR head. Furthermore, according to a further aspect of the invention a stack of GMR heads may be reinitialized having the same orientation to preclude inversion of the reset magnetic fields on half of the heads. In addition, improvements in re-initializing GMR heads is provided by implementing wave shaping. The invention can also provide re-initialization of GMR heads at different points in the manufacturing process. | ||||||
| 190 | Thin-film magnetic head, magnetoresistance effect magnetic head and composite magnetic head | US833186 | 1997-04-04 | US5822159A | 1998-10-13 | Munekatsu Fukuyama; Yasuo Sasaki; Yutaka Soda; Koji Fukumoto; Tetsuo Sekiya |
| A thin-film magnetic head, a magnetoresistance effect magnetic head and an MR inductive head are disclosed. The thin-film magnetic head has one of thin-film magnetic cores stacked on a substrate and formed of two magnetic films and a non-magnetic film held between them, with a current flowing through the thin-film magnetic core in the direction of hard axis thereof. The magnetoresistance effect magnetic head has one of a pair of shield cores having a magnetoresistive element between them formed of two magnetic films and a non-magnetic film held between them, the magnetoresistive element being electrically connected to the shield core, with a sense current flowing through the shield core. The current flowing through the one shield core via the magnetoresistive element is preferably an AC of decrement amplitude for demagnetizing the shield core along with a DC sense current. Also, this current preferably flows in the direction of hard axis of the shield core so that magnetic properties of the shield core are stabilized or demagnetized by the magnetic field generated in the direction of easy axis. The MR inductive head has a second thin-film magnetic core as a common magnetic body of an MR head and an inductive head on one substrate, formed of two magnetic films and a non-magnetic film held between them, with a current flowing through the second thin-film magnetic core in the direction of hard axis thereof. | ||||||
| 191 | Apparatus for detecting a magnetic field using a giant magnetoresistance effect multilayer and method for preventing an output reduction of the multilayer | US851959 | 1997-05-06 | US5798896A | 1998-08-25 | Satoru Araki; Osamu Shinoura; Yuuichi Sato; Yuuji Honda |
| For preventing output drop with time of a MR magnetic head or similar apparatus including a magnetic field sensor in the form of a giant magnetoresistive element of the induced ferrimagnetic or spin-valve type in which antiparallelism of magnetization is induced between the magnetic layers by external magnetization, a magnetic field detecting apparatus comprising a magnetic field sensor using a giant magnetoresistive multilayer film of the induced ferrimagnetic type or the like includes a magnetic field generating means such as a permanent magnet. The magnetic field sensor is moved to the proximity of the magnetic field generating means and placed within the magnetic field when the magnetic field sensor is out of use or its detection sensitivity drops. | ||||||
| 192 | Method and apparatus for reducing transition time for a magnetic head to switch from a write made to a read mode by reducing a maximum current value at different rates | US571760 | 1995-12-13 | US5724201A | 1998-03-03 | Jean-Luc Jaffard; Yann Desprez-Le Goarant |
| A device for switching a read head from a write mode to a read mode includes a voltage ramp generating circuit, generating and outputting a voltage ramp after a write operation; a variable current source for discharging an initial current of the read head, wherein a current output by the current source is controlled proportionally to the slope between the beginning of the voltage ramp and a first threshold of the ramp, the current source having an initial maximum value higher than the initial current of the head; and an accentuating circuit for accentuating the ramp slope between the beginning of the ramp and a time when the current output by the variable current source becomes equal to the initial current present in the head. | ||||||
| 193 | Magnetic device and method for locally controllably altering magnetization direction | US767461 | 1996-12-16 | US5691865A | 1997-11-25 | Mark T. Johnson; Friedrich J. A. Den Broeder; Jelto W. Smits |
| A device and method for controllably locally altering the magnetization direction in a body of magnetic material, whereby a layer of at least one of non-metallic material and a semi-metallic material is disposed on a surface of the body, on which layer is provided a body of magnetic material having a fixed magnetization direction, whereby both bodies of magnetic material are magnetically coupled across the interposed layer, the nature of this magnetic coupling being locally alterable by means of locally subjecting the layer to a controllable electric field. | ||||||
| 194 | Apparatus for detecting a magnetic field using a giant magnetoresistance effect multilayer | US198584 | 1994-02-18 | US5657190A | 1997-08-12 | Satoru Araki; Osamu Shinoura; Yuuichi Sato; Yuuji Honda |
| For preventing output drop with time of a MR magnetic head or similar apparatus, a magnetic field sensor in the form of a giant magnetoresistive element of the induced ferrimagnetic or spin-valve type in which antiparallelism of magnetization is induced between the magnetic layers by external magnetization. A magnetic field detecting apparatus including a magnetic field sensor using a giant magnetoresistive multilayer film of the induced ferrimagnetic type or the like includes a magnetic field generating means such as a permanent magnet. The magnetic field sensor is moved to the proximity of the magnetic field generating means and placed within the magnetic field when the magnetic field sensor is out of use or its detection sensitivity drops. | ||||||
| 195 | Magnetic reinitialization of thin film magnetoresistive reproducing heads at the suspension level of media drive manufacturing | US463391 | 1995-06-05 | US5617289A | 1997-04-01 | Samir E. Abboud; Nickolas C. Apuzzo; Jeffrey B. Brown; Earl A. Cunningham; David M. Hannon; Raymond P. Mallette; Paul S. Tyler; Steven H. Voss; Albert J. Wallash |
| The magnetic states of MR reproducing heads are reinitialized during media drive manufacturing by applying initializing magnetic fields to the transducers after they have been manufactured and incorporated into media drive assemblies. | ||||||
| 196 | Magnetic field sensor | US517156 | 1995-08-21 | US5600297A | 1997-02-04 | Jacobus J. M. Ruigrok; Martinus A. M. Gijs; Jacques C. S. Kools; Reinder Coehoorn; Wiepke Folkerts |
| A device for detecting a magnetic field, which device comprises a magneto-resistive multilayer structure comprising a first magnetic layer (1) which is separated from a second magnetic layer by an interposed non-magnetic layer, the multilayer structure having a first in-plane reference axis (R.sub.1) coinciding with the direction in which magnetic flux is offered to the multilayer structure during operation, and a second in-plane reference axis (R.sub.2) which is perpendicular to the first reference axis (R.sub.1), whereby the magnetic easy axis (E.sub.1) of the first magnetic layer (1) is canted through an acute in-plane angle .alpha. with respect to the second reference axis (R.sub.2), and the magnetic easy axis (E.sub.2) of the second magnetic layer is canted in the opposite sense through an acute in-plane angle .beta. with respect to the second reference axis (R.sub.2). Such a device lends itself to application in a magnetic head, for sensitive retrieval of magnetically-encoded data from a carrier in the form of a tape, disc or card. | ||||||
| 197 | Actuator and file level initialization of magnetoresistive transducers | US221813 | 1994-04-01 | US5576908A | 1996-11-19 | Glen A. Garfunkel; Mike P. Salo; Akihiko Aoyagi; Hiroshi Yanagisawa; Hiroshima Terashima; Kenji Kuroki |
| In a disk drive actuator head stack assembly, magnetic transducers including magnetoresistive (MR) read heads are connected to a current source and configured to provide an MR sensor current to each MR head wherein the direction of current flow for the MR sensor current in each MR head is the same relative to the actuator for all of the MR heads in the actuator head stack. This configuration allows all of the MR heads in the head stack assembly to be initialized simultaneously by applying a homogeneous magnetic field to the head stack assembly, thus providing the capability of initializing the MR heads at the actuator or disk drive level rather than requiring that the MR heads be initialized individually. | ||||||
| 198 | Magnetic recording and reproducing apparatus having magneto-resistance effect element | US902880 | 1992-06-23 | US5436772A | 1995-07-25 | Tetsuo Sekiya; Fumi Sugawara; Hideo Suyama |
| A magneto-resistance/inductive integrated composite magnetic head which has a stabilized reproduction output and is high in reliability. The magnetic head comprises a composite magnetic head including a magneto-resistance effect type head and an inductive type head integrated with each other and a recording coil, and an electric circuit for supplying, after recording, the recording coil of the composite magnetic head with an electric current which attenuates in a fashion of an alternating current from a value of a recording current or a value around or higher than such value of a recording current to another value in the proximity of the zero level. | ||||||
| 199 | Degausser for magnetic stripe card transducing system | US111220 | 1993-08-24 | US5396369A | 1995-03-07 | Robert S. Deland, Jr.; Richard P. Manning |
| A device for degaussing magnetic transducers used with magnetic stripe cards includes a degaussing unit that drives a magnetic transducer with an electrical pulse, or a gradually increasing drive frequency, to eliminate the residual magnetism of the transducer. Logic circuitry controls the device to degauss with little or no additional equipment and avoids damage to the recordings, as on low-coercivity magnetic stripe cards. | ||||||
| 200 | Electrical means to diminish read-back signal waveform distortion in recording heads | US73187 | 1993-06-08 | US5392169A | 1995-02-21 | Bernell E. Argyle; Anthony P. Praino; Mark E. Re; Rudolf Schafer; Shinji Takayama; Philip L. Trouilloud |
| A method and apparatus for conditioning a magnetic read/write head to substantially eliminate read-back pulse distortions associated with unfavorable magnetic domain patterns in the head stores the polarity of the last write current pulse of a write pulse train applied to the head-coils. This polarity is compared to a pre-determined reset current pulse polarity. If the last write current polarity is opposite to the reset current polarity, then a reset pulse, or a series of pulses, having the pre-determined reset polarity is applied to the head prior to performing a read operation with the head. The pre-determined reset polarity corresponds to the polarity that resets the head to the magnetic domain state most preferred for reading due to reduction of read-back distortion. The reset pulse, or pulse train, according to the present invention is of constant polarity. If the last write current pulse polarity is the same as the reset polarity, then no reset pulse is applied to the head. Prior to applying the reset pulse, the head is either re-positioned or, if not re-positioned, the reset pulse is applied to the head only when it is flying over a sector gap. | ||||||
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