Treating To Affect Magnetic Properties Patents (Class 29/603.08)
  • Publication number: 20020145834
    Abstract: Each of the first and second shield gap films has a highly insulative film made of aluminum oxide. The highly insulative film has the insulating properties improved by heating. The insulating properties may be improved by heating after deposition or by depositing while heating. This heating allows the highly insulative film to have a reduced pinhole density and an increased dielectric breakdown field. Therefore, the insulating properties can be ensured even if a shield gap length is reduced, and thus it is possible to adapt to an increase in a recording density of a recording medium. The highly insulative film may have the insulating properties improved by exposing the film surface to an oxygen-plasma-containing atmosphere or oxygen-ion-containing atmosphere after deposition.
    Type: Application
    Filed: October 4, 1999
    Publication date: October 10, 2002
    Inventors: TORU INOUE, KOICHI TERUNUMA
  • Publication number: 20020131218
    Abstract: A GMR magnetic sensor is described. The sensor uses one antiferromagnetic layer for stabilizing the pinned layer and another antiferromagnetic layer for providing magnetic bias stabilization of the free layer. Both antiferromagnetic layers are made of the same material and are initialized in the same process step.
    Type: Application
    Filed: March 14, 2001
    Publication date: September 19, 2002
    Inventor: Robert S. Beach
  • Patent number: 6436200
    Abstract: There is disclosed a method for preparing a magnetic head having a high-speed magnetic recording ability. A resist insulating layer 70 is formed on a coil, a magnetic pole layer 41 is formed on the resist insulating layer 70, and a laminate 10 including the resist insulating layer 70 and the magnetic pole layer 41 is heated so that the resist insulating layer 70 is allowed to shrink.
    Type: Grant
    Filed: March 23, 2000
    Date of Patent: August 20, 2002
    Assignee: Fujitsu Limited
    Inventors: Teruo Kiyomiya, Yuji Uehara
  • Patent number: 6430014
    Abstract: A free layer of an AP pinned spin valve sensor can be properly biased when the pinning layer is metallic and no gap offset is provided by counterbalancing a net demagnetizing field HD and a net sense current field HI by a ferromagnetic coupling field HF and a demagnetizing field from a biasing layer HB. The biasing layer is composed of a high resistance material which is preferably cobalt iron niobium (CoFeNb) or cobalt iron niobium hafnium (CoFeNbHf). A thickness of a copper spacer layer is selected so that the ferromagnetic coupling field HF is either positive or negative, depending upon the direction of the sense current field IS conducted through the sensor and the thicknesses of first and second AP pinned layers of an AP pinned layer structure are selected so that the net demagnetizing field HD supports the net sense current field HI.
    Type: Grant
    Filed: August 9, 2000
    Date of Patent: August 6, 2002
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Patent number: 6419552
    Abstract: In a thin-film magnetic head manufacturing method and apparatus, lapping is continued until the MR height of a magnetoresistive sensor falls into a finish tolerance range and the lapping time from the beginning of lapping exceeds a predetermined time, thereby substantially reducing the recession between an ABS of a slider bar and a surface of a thin-film magnetic element opposing a recording medium.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: July 16, 2002
    Inventors: Masato Katoh, Shigenobu Miyajima
  • Patent number: 6413325
    Abstract: A method of manufacturing a thin-film magnetic head with a SVMR element which includes first and second layers of a ferromagnetic material (free and pinned layers) separated by a layer of non-magnetic electrically conductive material, and a layer of anti-ferromagnetic material formed in physical contact with the pinned layer. The method has a first temperature annealing (pin annealing) step of annealing the SVMR element under application of magnetic field to provide exchange coupling between the pinned layer and the anti-ferromagnetic material layer so that the pinned layer is pinned toward a predetermined direction, and a second temperature annealing (free layer annealing) step of annealing the SVMR element so that axis of easy magnetization of the free layer orients a direction substantially perpendicular to the predetermined direction. The free layer annealing is performed at a temperature lower than 150° C.
    Type: Grant
    Filed: November 4, 1999
    Date of Patent: July 2, 2002
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Satoru Araki, Haruyuki Morita
  • Publication number: 20020078549
    Abstract: A method for manufacturing a magnetic encoder is disclosed, wherein the magnetic encoder may be used with a sensor on a semiconductor sensor chip that may be placed opposite the magnetic encoder, and is capable of providing codes as represented by a sequence of pulses generated by the magnetic forces. According to the method, an unvulcanized raw rubber is provided, to which a magnetic ferrite powder is added. The resulting mixture composed of the unvulcanized raw rubber and magnetic ferrite powder is then passed through a rolling machine or an extruding machine where the mixture is formed into a sheet blank that contains the magnetic ferrite powder aligned regularly in a particular orientation, or alternatively may be passed through the extruding machine, followed by being passed through the rolling machine, where the mixture is formed into a sheet blank that contains the magnetic ferrite powder aligned regularly in the particular orientation.
    Type: Application
    Filed: October 24, 2001
    Publication date: June 27, 2002
    Inventor: Yoshihiko Yamaguchi
  • Publication number: 20020078550
    Abstract: There is disclosed a manufacturing method of a magnetoresistive element of the present invention, comprising: a step of preparing a substrate having a thermal conductivity in a range of 5 to 150 Wm−1K−1; a substrate cooling step of moving the substrate into a vacuum cooling chamber, and cooling the substrate at an absolute temperature of 200 K or less in the vacuum cooling chamber; and a laminated film forming step of moving the cooled substrate into a vacuum film forming chamber, fixing the substrate to a substrate holder, and forming a magnetoresistive laminated film on the substrate while rotating the substrate, so that the manufacturing method of the magnetoresistive element is little in dispersion of element property, high in reliability, and superior in productivity.
    Type: Application
    Filed: November 5, 2001
    Publication date: June 27, 2002
    Applicant: TDK Corporation
    Inventors: Koji Shimazawa, Yoshihiro Tsuchiya
  • Patent number: 6364964
    Abstract: The SVMR element has a non-magnetic metallic thin-film layer, first and second ferromagnetic thin-film layers (free and pinned layers) formed to sandwich the non-magnetic metallic thin-film layer and an anti-ferromagnetic thin-film layer formed in contact with a surface of the second ferromagnetic thin-film layer. This surface is opposite to the non-magnetic metallic thin-film layer. The first ferromagnetic thin-film layer has a two-layers structure of a NiFe layer and a CoFe layer. The manufacturing method includes a step of depositing the first ferromagnetic thin-film layer, the non-magnetic metallic thin-film layer, the second ferromagnetic thin-film layer and the anti-ferromagnetic thin-film layer, and a step of annealing, thereafter, the deposited layers so that change in magnetostriction depending upon variation of a thickness of the NiFe layer becomes small.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: April 2, 2002
    Assignee: TDK Corporation
    Inventors: Tetsuro Sasaki, Noriyuki Ito, Koichi Terunuma
  • Patent number: 6364961
    Abstract: A method is disclosed for magnetizing a magnetic system including a ferromagnetic layer magnetized in a first direction and an anti-ferromagnetic layer provided on said ferromagnetic layer in exchange coupling therewith. The method includes a first thermal annealing process including the sub-steps of annealing the magnetic system in a first annealing state, and applying a magnetic field to the magnetic system in a second direction different from the first direction, while maintaining the magnetic system in the first annealing state. A second thermal annealing process includes the sub-steps of annealing the magnetic system after the first thermal annealing process, to a second annealing state, and applying a magnetic field in a third direction different from the second direction while maintaining the magnetic system in the second annealing state.
    Type: Grant
    Filed: November 5, 1999
    Date of Patent: April 2, 2002
    Assignee: Fujitsu Limited
    Inventors: Keiichi Nagasaka, Yutaka Shimizu, Hitoshi Kishi, Atsushi Tanaka
  • Publication number: 20020035777
    Abstract: With negative pressure sliders having step bearings, there are variations in flying height resulting from variations in shape factors, such as the step bearing depth. In order to achieve lower flying height, it is considered necessary to reduce the variation in flying height caused by the variation in curvature of the air bearing surface and the variation in flying height caused by the variation in the shapes of the step bearings. The curvature of the air bearing surface of the slider can be observed in the pre-cut row bar condition or in a unit product condition. Shape data of the magnetic head slider can be input, such as the step bearing depth, etc., so as to calculate the predicted flying height of the slider An arithmetic processing unit calculates an adjusted target curvature from the difference between the predicted flying height and the target flying height.
    Type: Application
    Filed: August 23, 2001
    Publication date: March 28, 2002
    Inventors: Kiyoshi Hashimoto, Masaaki Matsumoto
  • Patent number: 6358332
    Abstract: A process for resetting or initially establishing the magnetic orientation of one or more spin valves in a magnetoresistive read head with improved robustness. The spin valve includes subcomponents such as an antiferromagnetic layer, a ferromagnetic pinned layer, a conductive layer, a free layer, and a hard bias layer. A first external magnetic field is first applied to the spin valve sensor, this field having a first orientation relative to the spin valve sensor. During application of the first external magnetic field, a pulse of electrical current is directed through the spin valve sensor in a first direction, preferably parallel to the magnetic orientation of the external field. The current waveform brings the antiferromagnetic layer of the spin valve past its blocking temperature, freeing its magnetic orientation. The first external field exerts a robust bias upon the antiferromagnetic layer in the desired direction.
    Type: Grant
    Filed: January 13, 2000
    Date of Patent: March 19, 2002
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Patent number: 6355115
    Abstract: A method is disclosed for fabricating a spin-valve magnetic head including a layered body of a first ferromagnetic layer having a first easy axis of magnetization extending in a first direction, a non-magnetic layer formed on the first ferromagnetic layer, a second ferromagnetic layer provided on the non-magnetic layer, and an anti-ferromagnetic layer provided on the second ferromagnetic layer in exchange coupling therewith. The method includes a first thermal annealing process with the steps of annealing the layered body in a first annealing state and applying a magnetic field to the layered body in a second direction different from the first direction, while maintaining the layered body in the first annealing state.
    Type: Grant
    Filed: November 5, 1999
    Date of Patent: March 12, 2002
    Assignee: Fujitsu Limited
    Inventors: Keiichi Nagasaka, Yutaka Shimizu, Hitoshi Kishi, Atsushi Tanaka
  • Patent number: 6339329
    Abstract: A method for manufacturing a GMR bridge detector as well as the bridge detector itself in which magnetoresistive resistors are interconnected in the form of a bridge to detect a magnetic field. The resistors consist of a material that exhibits the giant magnetoresistive ratio (GMR) effect. The magnetoresistive sensitivity of the individual resistors is produced through annealing. The annealing of the resistors takes place through selective feeding of a current that is sufficient for reaching the temperature required for annealing into the bridge connections. Depending on the wiring of the bridge connections, the resistors are provided with the property necessary for the GMR effect either singly or in pairs. As the material for the resistors, in particular, a material of the class of discontinuous multilayer materials, particularly NiFe/Ag, is used in which the GMR property is produced through single annealing at a specific temperature.
    Type: Grant
    Filed: April 29, 1999
    Date of Patent: January 15, 2002
    Assignee: Robert Bosch GmbH
    Inventors: Christian Neumann, Klaus Marx, Franz Jost, Martin Freitag, Dietmar Senghaas
  • Patent number: 6322640
    Abstract: A method for forming a magnetically biased magnetoresistive (MR) layer. There is first provided a substrate. There is then formed over the substrate a ferromagnetic magnetoresistive (MR) material layer. There is then forming contacting the ferromagnetic magnetoresistive (MR) material layer a magnetic material layer formed of a first crystalline phase, where the magnetic material layer is formed of a crystalline multiphasic magnetic material having the first crystalline phase which does not appreciably antiferromagnetically exchange couple with the ferromagnetic magnetoresistive (MR) material layer and a second crystalline phase which does appreciably antiferromagnetically exchange couple with the ferromagnetic magnetoresistive (MR) material layer.
    Type: Grant
    Filed: January 24, 2000
    Date of Patent: November 27, 2001
    Assignee: Headway Technologies, Inc.
    Inventors: Rongfu Xiao, Chyu-Jiuh Torng, Hui-Chuan Wang, Jei-Wei Chang, Cherng-Chyi Han, Kochan Ju
  • Patent number: 6308400
    Abstract: A method of forming a DSMR head comprises the steps of forming a first ferromagnetic (FM) strip on a substrate with a first anti-FM (AFM) pinning layer over a portion of the first ferromagnetic strip, the first AFM pinning layer being composed of a first material. Then perform a first high temperature annealing step. Form a non-magnetic layer over the strip and the pinning layer. Then form a second FM strip on the non-magnetic layer, and form a second AFM pinning layer over a portion of the second FM strip, with a second AFM pinning layer being composed identically of the first material. Perform a second high temperature annealing step on the first and second FM strips and the first and second pinning layers and the intermediate non-magnetic layer in the presence of a second magnetic field antiparallel to the first magnetic field. A head with NiFe FM strips and FeMn or MnPt, etc, AFM layers for both strips is provided.
    Type: Grant
    Filed: August 6, 1999
    Date of Patent: October 30, 2001
    Assignee: Headway Technologies, Inc.
    Inventors: Simon H. Liao, Min Li
  • Patent number: 6302970
    Abstract: A manufacturing method of a thin-film magnetic head with a spin valve effect MR read sensor includes a temperature-annealing step of firmly fixing the direction of the pinned magnetization in the spin valve effect MR sensor. The temperature-annealing step is executed by a plurality of times.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: October 16, 2001
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Manabu Ohta, Tetsuro Sasaki
  • Patent number: 6299507
    Abstract: In a thin-film magnetic head manufacturing method and apparatus, lapping is continued until the MR height of a magnetoresistive sensor falls into a finish tolerance range and the lapping time from the beginning of lapping exceeds a predetermined time, thereby substantially reducing the recession between an ABS of a slider bar and a surface of a thin-film magnetic element opposing a recording medium.
    Type: Grant
    Filed: January 20, 2000
    Date of Patent: October 9, 2001
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masato Katoh, Shigenobu Miyajima
  • Patent number: 6295718
    Abstract: Within a method for forming a magnetoresistive (MR) sensor element there is first provided a substrate. There is then formed over the substrate a first magnetoresistive (MR) layer having formed contacting the first magnetoresistive (MR) layer a magnetically biased first magnetic bias layer biased in a first magnetic bias direction with a first magnetic bias field strength. There is also formed separated from the first magnetoresistive (MR) layer by a spacer layer a second magnetoresistive (MR) layer having formed contacting the second magnetoresistive (MR) layer a magnetically un-biased second magnetic bias layer.
    Type: Grant
    Filed: August 16, 1999
    Date of Patent: October 2, 2001
    Assignee: Headway Technologies, Inc.
    Inventors: Min Li, Simon H. Liao
  • Patent number: 6291087
    Abstract: A method for forming a magnetoresistive (MR) sensor element, and a magnetoresistive sensor element fabricated in accord with the method. There is first provided a substrate. There is then formed over the substrate a magnetoresistive (MR) layer comprising: (1) a bulk layer of the magnetoresistive (MR) layer formed of a first magnetoresistive (MR) material optimized to provide an enhanced magnetoresistive (MR) resistivity sensitivity of the magnetoresistive (MR) layer; and (2) a surface layer of the magnetoresistive (MR) layer formed of a second magnetoresistive (MR) material optimized to provide an enhanced magnetic exchange bias when forming a magnetic exchange bias layer upon the surface layer of the magnetoresistive (MR) layer. Finally, there is then formed upon the surface layer of the magnetoresistive (MR) layer the magnetic exchange bias layer. The method contemplates an magnetoresistive (MR) sensor element fabricated in accord with the method.
    Type: Grant
    Filed: June 21, 1999
    Date of Patent: September 18, 2001
    Assignee: Headway Technologies, Inc.
    Inventors: Rongfu Xiao, Chyu-Jiuh Torng, Kochan Ju, Cheng Horng, Jei-Wei Chang
  • Patent number: 6286200
    Abstract: A method of making a second pole piece layer that has a yoke portion between a pole tip portion and a back gap portion comprising the steps of forming a first photoresist layer that is sensitive to a first bandwidth of light, forming a second photoresist layer on the first photoresist layer that is sensitive to a second bandwidth of light that is different from the first bandwidth of light, after forming the first and second photoresist layers, photopatterning the second photoresist layer with the second bandwidth of light to provide an opening at pole tip, yoke and back gap sites wherein the pole tip, yoke and back gap sites define perimeters for the pole tip, yoke and back gap portions respectively, after photopatterning the second photoresist layer, photopatterning the first photoresist layer with the first bandwidth of light to provide openings at the pole tip, yoke and back gap sites and then plating the pole tip, yoke and back gap portions of the second pole piece layer in the openings of the first and
    Type: Grant
    Filed: July 23, 1999
    Date of Patent: September 11, 2001
    Assignee: International Business Machines Corporation
    Inventors: Bin Huang, Edward Hinpong Lee
  • Patent number: 6275028
    Abstract: 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.
    Type: Grant
    Filed: December 23, 1998
    Date of Patent: August 14, 2001
    Assignee: International Business Machines Corporation
    Inventors: Takao Matsui, Tatsuya Endo, Hiroaki Suzuki, Kenji Kuroki, Katsushi Yamaguchi, Hideo Asano
  • Publication number: 20010012188
    Abstract: A spin-valve thin-film magnetic element includes a substrate, a composite formed thereon, and electrode layers formed on both sides of the composite. The composite includes an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer, a mean-free-path-extending layer, and an exchange bias layer. The mean-free-path-extending layer may be a back layer or a mirror reflective layer. The mean-free-path-extending layer extends the mean free path of spin-up conduction electrons in the spin-valve thin-film magnetic element. This spin-valve thin-film magnetic element meets trends toward a narrower track width.
    Type: Application
    Filed: January 30, 2001
    Publication date: August 9, 2001
    Applicant: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Kenji Honda, Yoshihiko Kakihara
  • Patent number: 6270588
    Abstract: A thin-film magnetic head having a spin valve effect multi-layered structure including a non-magnetic electrically conductive material layer, first and second ferromagnetic material layers separated by the non-magnetic electrically conductive material layer, and an anti-ferromagnetic material layer formed adjacent to and in physical contact with one surface of the second ferromagnetic material layer. This one surface is an opposite side from the non-magnetic electrically conductive material layer and the multi-layered structure has ends at its track-width direction. The head also has longitudinal bias means formed at both the track-width ends of the multi-layered structure, for providing a longitudinal magnetic bias to the multi-layered structure.
    Type: Grant
    Filed: March 19, 1999
    Date of Patent: August 7, 2001
    Assignee: TDK Corporation
    Inventors: Ken-ichi Takano, Masato Takahashi, Nobuya Oyama
  • Publication number: 20010009063
    Abstract: A spin valve thin-film magnetic device is provided, in which the asymmetry can be reduced. The spin valve thin-film magnetic device comprises a free magnetic layer and a first and a second fixed magnetic layer, which are provided respectively at each side of the free magnetic layer in the thickness direction thereof. In the spin valve thin-film magnetic device, the free magnetic layer is composed of a first and a second ferromagnetic free layer, in which the entire free magnetic layer is in a ferrimagnetic state, the first fixed magnetic layer is composed of a first and a second pinned ferromagnetic layer, in which the entire first fixed magnetic layer is in a ferrimagnetic state, and the second fixed magnetic layer is composed of a third and a fourth pinned ferromagnetic layer, in which the entire second fixed magnetic layer is in a ferrimagnetic state.
    Type: Application
    Filed: January 17, 2001
    Publication date: July 26, 2001
    Applicant: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Kenichi Tanaka, Yosuke Ide, Fumihito Koike, Naoya Hasegawa
  • Patent number: 6256863
    Abstract: A magnetic yoke having a magnetic gap provided in the side of the surface facing the medium is disposed on the surface of a substrate. An MR film is disposed on the surface of the magnetic yoke substantially parallel to the substrate with a predetermined separation from the surface S facing the medium. At least both end portions of the MR film are magnetically coupled to the magnetic yoke. A pair of leads for supplying sensing current to the MR film have magnetic lead portions formed from the same magnetic layers as the magnetic yoke. The magnetic lead portions curb deterioration of MR head properties and yield reduction during formation of the leads. Furthermore, a bias magnetic field is applied to the magnetic yoke and the MR film at least during operation of the head. This bias magnetic field is for instance provided by a magnetic field induced by the electric current. Alternatively, a magnetic field induced by the electric current is applied while heat-processing the magnetic yoke.
    Type: Grant
    Filed: March 11, 1997
    Date of Patent: July 10, 2001
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuhiro Saito, Akiko Saito, Hitoshi Iwasaki, Akihiko Tsutai, Hiroaki Yoda, Tadahiko Kobayashi, Yuichi Ohsawa, Masahi Sahashi, Yuzo Kamiguchi
  • Patent number: 6230390
    Abstract: A dual stripe magnetoresistive (DSMR) sensor element, and a method for fabricating the dual stripe magnetoresistive (DSMR) sensor element. When fabricating the dual stripe magnetoresistive (DSMR) sensor element while employing the method, there are employed two pair of patterned magnetic biasing layers formed of a single magnetic biasing material. The two pair of patterned magnetic biasing layers bias a pair of patterned magnetoresistive (MR) layers in a pair of opposite canted directions.
    Type: Grant
    Filed: October 30, 1998
    Date of Patent: May 15, 2001
    Assignee: Headway Technologies, Inc.
    Inventors: Yimin Guo, Kochan Ju, Po-Kang Wang, Cherng-Chyi Han, Hui-Chuan Wang
  • Patent number: 6221172
    Abstract: A spin-valve magnetoresistive element includes a plurality of layers. The magnetic moment of a first pinned magnetic layer is smaller than the magnetic moment of a second pinned magnetic layer. In this case, a magnetic field of 100 to 1,000 Oe is applied in a direction opposite to the direction for which obtaining of magnetization for the first pinned magnetic layer is desired, or a magnetic field of 5 kOe or greater is applied in the same direction as the direction for which obtaining of magnetization for the first pinned magnetic layer is desired. Thus, a first magnetization of the first pinned magnetic layer and the magnetic moment of a second pinned magnetic layer can be maintained in an antiparallel state.
    Type: Grant
    Filed: July 20, 1999
    Date of Patent: April 24, 2001
    Assignee: Alps Electric Co., Inc.
    Inventors: Masamichi Saito, Naoya Hasegawa