Having Giant Magnetoresistive (gmr) Or Colossal Magnetoresistive (cmr) Sensor Formed Of Multiple Thin Films Patents (Class 360/324)
  • Publication number: 20090046396
    Abstract: The present invention relates to a magnetic recording medium comprising a magnetic layer comprising a ferromagnetic powder and a binder on a nomnagnetic support. A product, Mr?, of a residual magnetization Mr of the magnetic layer and a thickness ? of the magnetic layer is equal to or greater than 2 mT•?m and equal to or less than 12 mT•?m, a squareness in a perpendicular direction is equal to or greater than 0.4 and equal to or less than 0.7, and a squareness in a longitudinal direction is equal to or greater than 0.3 but less than 0.6.
    Type: Application
    Filed: March 30, 2007
    Publication date: February 19, 2009
    Applicant: FUJIFILM CORPORATION
    Inventors: Takeshi Nagata, Hitoshi Noguchi
  • Publication number: 20090034133
    Abstract: A magnetic field detecting element comprising: a stack including an upper magnetic layer, a lower magnetic layer and a non-magnetic intermediate layer sandwiched between said upper magnetic layer and said lower magnetic layer, wherein magnetization directions of said upper magnetic layer and said lower magnetic layer change in accordance with an external magnetic field; an upper shield electrode layer and a lower shield electrode layer which are provided in a manner that they sandwich said stack therebetween in a direction of stacking of said stack, wherein said upper shield electrode layer and said lower shield electrode layer supply sense current in the direction of stacking and magnetically shield said stack; a bias magnetic layer which is provided on a surface of said stack, the surface being opposite to an air bearing surface of said stack, wherein said bias magnetic layer applies a bias magnetic field to said upper magnetic layer and to said lower magnetic layer in a direction perpendicular to the air b
    Type: Application
    Filed: July 30, 2007
    Publication date: February 5, 2009
    Inventors: Daisuke MIYAUCHI, Takahiko MACHITA
  • Publication number: 20090034132
    Abstract: A magnetic field detecting element comprising: a stack including an upper magnetic layer, a lower magnetic layer and a non-magnetic intermediate layer sandwiched between said upper magnetic layer and said lower magnetic layer, wherein magnetization directions of said upper magnetic layer and said lower magnetic layer change in accordance with an external magnetic field; an upper shield electrode layer and a lower shield electrode layer which are provided in a manner that they sandwich said stack therebetween in a direction of stacking of said stack, wherein said upper shield electrode layer and said lower shield electrode layer supply sense current in the direction of stacking and magnetically shield said stack; a bias magnetic layer which is provided on a surface of said stack, the surface being opposite to an air bearing surface of said stack, wherein said bias magnetic layer applies a bias magnetic field to said upper magnetic layer and to said lower magnetic layer in a direction perpendicular to the air b
    Type: Application
    Filed: July 30, 2007
    Publication date: February 5, 2009
    Inventors: Daisuke MIYAUCHI, Takahiko MACHITA
  • Patent number: 7486486
    Abstract: A magnetic device includes a first ferromagnetic layer in which magnetic layers and one or more nonmagnetic layers are alternately stacked, a second ferromagnetic layer having magnetization substantially fixed to a second direction, a third ferromagnetic layer provided between the first and second ferromagnetic layers and having a variable direction of magnetization, and a couple of electrodes configured to provide write current between the first and second ferromagnetic layers so that the direction of magnetization of the third ferromagnetic layer is determined depending on a direction of the current. At least one layer of the magnetic layers has magnetization substantially fixed to a first direction. Two or more layers of the magnetic layers are ferromagnetically coupled via the nonmagnetic layers. The ferromagnetic coupling has a strength such that a parallel magnetic alignment of the magnetic layers is maintained when the write current is passed.
    Type: Grant
    Filed: September 30, 2004
    Date of Patent: February 3, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Nakamura, Shigeru Haneda
  • Publication number: 20090009914
    Abstract: A spin-valve structure is provided, illustrating the layer structure used for the magnetic tunnel junction, by a method comprising the steps of providing a substrate, growing a ferromagnetic layer on the substrate, growing a tunnel barrier layer on the ferromagnetic layer, providing a first non-magnetic metallic contact on the ferromagnetic layer and providing a second non-magnetic metallic contact for the single ferromagnetic layer. Beside such a single sided structure a double-sided structure can be provided having e.g. a Ga0.94Mn0.06As/undoped GaAs/Ga0.94Mn0.06As trilayer structure on top of a semi-insulating GaAs substrate and an undoped LT-GaAs buffer layer. There is an inner square contact and a surrounding electrical back contact. This sample structure makes it possible to perform two-probe magnetoresistance measurements through both ferromagnets and the GaAs tunnel barrier. The resistance of the device is fully dominated by the vertical tunneling process through the tunnel barrier.
    Type: Application
    Filed: May 3, 2005
    Publication date: January 8, 2009
    Applicant: ETECH AG
    Inventors: Georg Schmidt, Charles Gould, Laurens W. Molenkamp, Christian Ruster
  • Publication number: 20090002897
    Abstract: The invention provides a giant magneto-resistive effect device (CPP-GMR device) having a CPP (current perpendicular to plane) structure comprising a multilayer device assembly comprising a fixed magnetization layer, a spacer layer, a free layer and a cap layer stacked one upon another in order, with a sense current applied in a stacking direction of the multilayer device assembly. In the rear of the multilayer device assembly, there is a refilled insulation layer formed, which is in contact with the rear end face of the multilayer device assembly and extends rearward, wherein the uppermost position P of the refilled insulation layer that is in contact with the rear end face of said multilayer device assembly lies at a rear end face of the cap layer and is set in such a way as to satisfy a relation: 0.2?(T2/T1)<1 where T1 is the thickness of the cap layer, and T2 is the absolute value of a distance from the uppermost portion of the cap layer down to the position P as viewed in a thickness direction.
    Type: Application
    Filed: June 26, 2007
    Publication date: January 1, 2009
    Applicant: TDK CORPORATION
    Inventors: Takahiko Machita, Daisuke Miyauchi
  • Publication number: 20090002893
    Abstract: The invention provides a giant magneto-resistive effect device (CPP-GMR device) having a CPP (current perpendicular to plane) structure comprising a spacer layer, and a fixed magnetized layer and a free layer stacked one upon another with said spacer layer interposed between them, with a sense current applied in a stacking direction, wherein the free layer functions such that the direction of magnetization changes depending on an external magnetic field, and the spacer layer comprises a first and a second nonmagnetic metal layer, each formed of a nonmagnetic metal material, and a semiconductor oxide layer interposed between the first and the second nonmagnetic metal layer, wherein the semiconductor oxide layer that forms a part of the spacer layer is made of zinc oxide, tin oxide, indium oxide, and indium tin oxide (ITO), the first nonmagnetic metal layer is made of Cu, and the second nonmagnetic metal layer is substantially made of Zn.
    Type: Application
    Filed: June 26, 2007
    Publication date: January 1, 2009
    Applicant: TDK CORPORATION
    Inventors: Yoshihiro Tsuchiya, Tomohito Mizuno, Shinji Hara
  • Patent number: 7471492
    Abstract: A magnetoresistive element has a first magnetic layer and a second magnetic layer separate from each other, the first magnetic layer and the second magnetic layer each having a magnetization whose direction is substantially pinned, and a non-magnetic conductive layer formed in contact with the first magnetic layer and the second magnetic layer and electrically connecting the first and second magnetic layers, the non-magnetic conductive layer forming a path of spin-polarized electrons from one of the magnetic layer to the other magnetic layer, the non-magnetic conductive layer comprising a portion located between the first magnetic layer and the second magnetic layer, the portion being a sensing area.
    Type: Grant
    Filed: July 22, 2004
    Date of Patent: December 30, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Hiromi Yuasa, Susumu Hashimoto, Hitoshi Iwasaki
  • Publication number: 20080316654
    Abstract: A magnetic sensor for detecting magnetism in two-axial directions or three-axial directions is constituted of a substrate, a silicon oxide film that is formed on the substrate so as to form the planar surface and slopes, a plurality of magnetoresistive elements, each of which is formed by laminating a free layer, a conductive layer, and a pin layer on the substrate, a plurality of lead films that are formed to connect the magnetoresistive elements in series, a CVD oxide film for covering the magnetoresistive elements, and a non-magnetic film that is formed between the magnetoresistive elements and the CVD oxide film so as to cover the periphery of the free layer with respect to each magnetoresistive element. Thus, it is possible for the magnetic sensor to include the magnetoresistive elements having superior hysteresis characteristics.
    Type: Application
    Filed: June 11, 2008
    Publication date: December 25, 2008
    Applicant: YAMAHA CORPORATION
    Inventor: Kokichi Aiso
  • Patent number: 7444739
    Abstract: A magnetic head fabrication process in which a stencil layer is deposited upon a plurality of sensor layers. A photoresist mask in the desired read track width is fabricated upon the stencil layer. A reactive ion milling step is then conducted to remove the unmasked portions of the stencil layer. Where the stencil layer is composed of an organic compound, such as Duramide and/or diamond-like-carbon, a reactive ion milling step utilizing oxygen species produces a stencil of the present invention having exceptionally straight side walls with practically no undercuts. Thereafter, an ion milling step is undertaken in which the sensor layers that are not covered by the stencil are removed. The accurately formed stencil results in correspondingly accurately formed side walls of the remaining central sensor layers. A magnetic head sensor structure having a desired read track width and accurately formed side walls is thus fabricated.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: November 4, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Michael Feldbaum, Wipul Pemsiri Jayasekara, Mustafa Michael Pinarbasi
  • Patent number: 7446981
    Abstract: This invention provides a high-output magnetic head with a high yield, which is capable of minimizing sense current leak or noise caused by a shift of the magnetic wall of an upper shield layer. In one embodiment, the magnetic head is fabricated so that the height of the upper surface of the refill film along the sensor height direction is the same as that of the magnetoresistance layer in a portion where the refill film along the sensor height direction comes in contact with the magnetoresistance layer and the distance from the upper surface of the refill film along the sensor height direction to the upper surface of the lower shield layer gradually increases in a region from the portion where the refill film along the sensor height direction comes in contact with the magnetoresistance layer to a point at a certain distance away from the portion.
    Type: Grant
    Filed: July 24, 2006
    Date of Patent: November 4, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Taku Shintani, Katsuro Watanabe, Nobuo Yoshida, Hisako Takei
  • Publication number: 20080253037
    Abstract: A thin-film magnetic head includes a lower magnetic shield layer, an MR multi-layered structure formed on the lower magnetic shield layer so that current flows in a direction perpendicular to surfaces of laminated layers, an insulation layer formed to surround the MR multi-layered structure, an additional metal layer laminated on at least the MR multi-layered structure, an upper electrode layer made of a soft magnetic material laminated on the additional metal layer and the insulation layer, and an upper magnetic shield layer laminated on the upper electrode layer. The additional metal layer has a multi-layered structure including a nonmagnetic metal layer and a soft magnetic layer laminated on the nonmagnetic metal layer, and has a length along a track-width direction of the MR multi-layered structure larger than a width of a magnetization-free layer in the MR effect multi-layered structure.
    Type: Application
    Filed: April 11, 2007
    Publication date: October 16, 2008
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Kazuki Sato, Kosuke Tanaka, Takayasu Kanaya, Naoki Ohta
  • Patent number: 7431961
    Abstract: In this invention, we replace low resistivity NiFe with high-resistivity FeNi for the FL2 portion of a composite free layer in a CIP GMR sensor in order to minimize current shunting effects while still retaining both magnetic softness and low magnetostriction. A process for manufacturing the device is also described.
    Type: Grant
    Filed: December 10, 2004
    Date of Patent: October 7, 2008
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui-Chuan Wang, Yun-Fei Li, Chyu-Jiuh Torng
  • Patent number: 7425456
    Abstract: A giant magnetoresistive memory device includes a magnetic sense layer, a magnetic storage layer, a non-magnetic spacer layer between the magnetic sense layer and the magnetic storage layer, and an antiferromagnetic layer formed in proximity to the magnetic storage layer. The antiferromagnetic layer couples magnetically in a controlled manner to the magnetic storage layer such that the magnetic storage layer has uniform and/or directional magnetization. Additionally or alternatively, an antiferromagnetic layer may be formed in proximity to the magnetic sense layer. The antiferromagnetic layer in proximity to the magnetic sense layer couples magnetically in a controlled manner to the magnetic sense layer such that the magnetic sense layer has uniform and/or directional magnetization.
    Type: Grant
    Filed: August 22, 2005
    Date of Patent: September 16, 2008
    Assignee: Honeywell International Inc.
    Inventor: Romney R. Katti
  • Publication number: 20080218912
    Abstract: An MR element includes: a free layer whose direction of magnetization changes in response to a signal magnetic field; a pinned layer whose direction of magnetization is fixed; and a spacer layer disposed between these layers. The spacer layer includes: a semiconductor layer made of an n-type semiconductor; and a Schottky barrier forming layer made of a metal material having a work function higher than that of the n-type semiconductor that the semiconductor layer is made of, the Schottky barrier forming layer being disposed in at least one of a position between the semiconductor layer and the free layer and a position between the semiconductor layer and the pinned layer, touching the semiconductor layer and forming a Schottky barrier at an interface between the semiconductor layer and itself The semiconductor layer is 1.1 to 1.7 nm in thickness, and the Schottky barrier forming layer is 0.1 to 0.3 nm in thickness.
    Type: Application
    Filed: March 9, 2007
    Publication date: September 11, 2008
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Satoshi Miura, Takeo Kagami, Tetsuro Sasaki
  • Publication number: 20080198513
    Abstract: A magnetic thin film has: a pinned layer whose magnetization direction is fixed with respect to an external magnetic field; a free layer whose magnetization direction is changed in accordance with the external magnetic field; and a non-magnetic spacer layer that is sandwiched between said pinned layer and said free layer, wherein sense current is configured to flow in a direction that is perpendicular to film surfaces of said pinned layer, said non-magnetic spacer layer, and said free layer. Said non-magnetic spacer layer has a first layer which includes SnO2, and a pair of second layers which are provided to sandwich said first layer, said second layers being made of a material which exhibits a higher corrosion potential than Sn.
    Type: Application
    Filed: February 20, 2007
    Publication date: August 21, 2008
    Inventors: Shinji HARA, Yoshihiro TSUCHIYA, Tomohito MIZUNO
  • Publication number: 20080192388
    Abstract: Improved performance uniformity among CPP magnetic read devices that include an oxide barrier has been achieved by fabricating the oxide layer from at least two separately formed CCP layers. Each CCP layer is given its own PIT and IAO treatment which is of shorter duration than the PIT/IAO treatment that is used when only a single CCP layer is formed.
    Type: Application
    Filed: February 9, 2007
    Publication date: August 14, 2008
    Inventors: Kunliang Zhang, Min Li, Yu-Hsia Chen
  • Publication number: 20080170336
    Abstract: The invention provides a giant magneto-resistive effect device (CPP-GMR device) having the CPP (current perpendicular to plane) structure comprising a spacer layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked one upon another with the spacer layer interposed between them, with a sense current applied in a stacking direction, wherein the spacer layer comprises a first nonmagnetic metal layer and a second nonmagnetic metal layer, each made of a nonmagnetic metal material, and a semiconductor oxide layer interposed between the first nonmagnetic metal layer and the second nonmagnetic metal layer, the semiconductor oxide layer that forms a part of said spacer layer contains zinc oxide as its main component wherein the main component zinc oxide contains an additive metal, and the additive metal is less likely to be oxidized than zinc.
    Type: Application
    Filed: January 3, 2008
    Publication date: July 17, 2008
    Applicant: TDK Corporation
    Inventors: Yoshihiro TSUCHIYA, Tomohito Mizuno, Kei Hirata, Koji Shimazawa, Shinji Hara
  • Patent number: 7394247
    Abstract: The invention discloses a sensor for 360-degree magnetic field angle measurement. It comprises multiple GMR (or MTJ) stripes with identical geometries except for their orientations. These are used as the building blocks for a pair of Wheatstone bridges that signal the direction of magnetization of their environment. The design greatly enhances sensitivity within GMR stripes and does not require an additional Hall sensor in order to cover the full 360 degree measurement range.
    Type: Grant
    Filed: July 26, 2007
    Date of Patent: July 1, 2008
    Assignee: Magic Technologies, Inc.
    Inventors: Yimin Guo, Grace Gorman, Po-Kang Wang
  • Publication number: 20080144231
    Abstract: Embodiments of the present invention provide a magnetic head incorporating a CPP-GMR device having a high output at a suitable resistance. According to one embodiment, in a Current Perpendicular to Plane-Giant Magneto Resistive (CPP-GMR) head comprising a pinned layer, a free layer, and a current screen layer for confining current therein, a planarization treatment is applied to the surface of the current screen layer, thereby allowing the current screen layer to have a fluctuation in film thickness thereof. As a result of the fluctuation being provided in the film thickness of the current screen layer, parts of the current screen layer, smaller in the film thickness, will be selectively turned into metal areas low in resistance, and as the metal areas low in resistance serve as current paths, effects of confining current can be adjusted by controlling the fluctuation in the film thickness.
    Type: Application
    Filed: November 29, 2007
    Publication date: June 19, 2008
    Applicant: Hitachi Global Storage Technologies Netherlands B. V.
    Inventors: Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya
  • Patent number: 7382588
    Abstract: A magnetic head includes first and second shield layers and a read sensor formed between and in electrical contact with the first and second shield layers. The read sensor includes a free layer structure; an antiparallel (AP) self-pinned structure which includes a first AP self-pinned layer, a second AP self-pinned layer, and an AP coupling layer formed between the first and the second AP self-pinned layers; and a non-magnetic spacer layer formed between the free layer structure and the AP self-pinned structure. The first AP self-pinned layer is formed in both a central region of the read sensor and in side regions adjacent the central region. Since thermal stability of the first AP self-pinned layer is proportional to its volume, extending the first AP self-pinned layer in the side regions improves the thermal stability to reduce the likelihood of amplitude flip in the self-pinned sensor.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: June 3, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7382584
    Abstract: The problem of increasing the output signal from a CCP-CPP GMR device without having it overheat has been overcome by placing materials that have different thermoelectric potentials on opposing sides of the spacer layer. Heat from the hot junction is removed at the substrate, which acts as a heat sink, resulting in a net local cooling of the confined current spacer layer, enabling it to operate at both higher input voltage increased reliability.
    Type: Grant
    Filed: July 6, 2005
    Date of Patent: June 3, 2008
    Assignee: Headway Technologies, Inc.
    Inventors: Yue Liu, Daniel G. Abels, Moris Dovek, Min Li, Pokang Wang, Mao-Min Chen
  • Publication number: 20080106827
    Abstract: The invention provides a CPP-GMR device comprising a spacer layer. The spacer layer comprises a first nonmagnetic metal layer and a second nonmagnetic metal layer, each formed of a nonmagnetic metal material, and a semiconductor layer interposed between the first nonmagnetic metal layer and the second nonmagnetic metal layer, and further comprises a work function control layer formed between the first nonmagnetic metal layer and the semiconductor layer and/or between the second nonmagnetic metal layer and the semiconductor layer. The semiconductor layer is an n-type semiconductor, and the work function control layer is made of a material having a work function smaller than that of said first nonmagnetic metal layer, and said second nonmagnetic metal layer.
    Type: Application
    Filed: October 31, 2007
    Publication date: May 8, 2008
    Applicant: TDK CORPORATION
    Inventors: Koji SHIMAZAWA, Yoshihiro Tsuchiya, Tomohito Mizuno, Kei Hirata
  • Patent number: 7365948
    Abstract: An exchange-coupled film includes a seed layer, an antiferromagnetic layer, and a ferromagnetic layer. The seed layer is formed at a thickness that is larger than the critical thickness, and the thickness of the seed layer is then decreased by etching so as to be smaller than or equal to the critical thickness. Thereby, a crystalline phase which extends through the seed layer from the upper surface to the lower surface can be formed, and/or the average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer can be set to be larger than the thickness of the seed layer. Consequently, a large exchange coupling magnetic field Hex can be generated between the antiferromagnetic layer and the ferromagnetic layer.
    Type: Grant
    Filed: July 21, 2004
    Date of Patent: April 29, 2008
    Assignee: Alps Electric Co., Ltd
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Publication number: 20080088982
    Abstract: Magnetic sensing chips and methods of fabricating the magnetic sensing chips are disclosed. A magnetic sensing chip as described herein includes an EMR sensor formed on a substrate from multiple semiconductor layers. One or more of the semiconductor layers form a quantum well comprising a two-dimensional electron gas (2DEG) or hole gas (2DHG). The magnetic sensing chip also includes one or more transistors formed on the substrate from the multiple semiconductor layers. The transistor(s) likewise include a quantum well comprising a 2DEG or 2DHG. The EMR sensor and the transistor(s) are connected by one or more connections so that the transistor(s) amplifies data signals from the EMR sensor.
    Type: Application
    Filed: October 16, 2006
    Publication date: April 17, 2008
    Inventors: Liesl Folks, Robert E. Fontana, Bruce A. Gurney, Klaas B. Klaassen, Stefan Maat
  • Patent number: 7355822
    Abstract: A ferromagnetic thin-film based magnetic field sensor having an electrically insulative intermediate layer with two major surfaces on opposite sides thereof with an initial film of an anisotropic ferromagnetic material on one of those intermediate layer major surfaces and a superparamagnetic thin-film on the remaining one of said intermediate layer major surfaces.
    Type: Grant
    Filed: February 22, 2006
    Date of Patent: April 8, 2008
    Assignee: NVE Corporation
    Inventors: James M. Daughton, Dexin Wang
  • Publication number: 20080080100
    Abstract: A magnetic sensor includes a magnetic oscillation element whose oscillation frequency changes depending on the magnitude of an external magnetic field, and an oscillation element provided in the vicinity of the magnetic oscillation element and oscillating at an oscillation frequency close to that of the magnetic oscillation element. The magnetic oscillation element includes a first fixed magnetization layer whose magnetization is fixed, a first magnetization oscillation layer, a first non-magnetic layer provided between the first fixed magnetization layer and the first magnetization oscillation layer, and a pair of electrodes for passing current perpendicularly to the film surfaces of the first fixed magnetization layer, the first magnetization oscillation layer, and the first non-magnetic layer. These two elements are used in combination with the passed current to acquire a high frequency oscillation signal generated from the magnetic oscillation element and the oscillation element.
    Type: Application
    Filed: June 22, 2007
    Publication date: April 3, 2008
    Inventors: Rie Sato, Koichi Mizushima, Kiwamu Kudo
  • Publication number: 20080080081
    Abstract: A method for inspecting a magnetic read/write head in which a magnetic recording part and a magnetic reproducing part are close to each other includes the steps of performing a magnetic recording operation with a load greater than a normal magnetic recording operation for the magnetic recording part, and inspecting the magnetic reproducing part after the magnetic recording operation with the load.
    Type: Application
    Filed: July 27, 2007
    Publication date: April 3, 2008
    Applicant: FUJITSU LIMITED
    Inventor: Endo Toshihiko
  • Patent number: 7348647
    Abstract: A digital magnetic memory cell device for read and/or write operations, having a soft-magnetic read and/or write layer system and at least one hard-magnetic reference layer system, which is designed as an AAF system and includes at least one reference layer, wherein the reference layer system has a layer section comprising at least one bias layer system with at least one ferrimagnetic layer, the magnetic moments of the bias layer system and of the reference layer being coupled in opposite directions via a coupling layer.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: March 25, 2008
    Assignee: Infineon Technologies AG
    Inventors: Roland Mattheis, Hugo Van Den Berg
  • Patent number: 7346977
    Abstract: A method for making a magnetoresistive read head so that the pinned ferromagnetic layer is wider than the stripe height of the free ferromagnetic layer uses ion milling with the ion beam aligned at an angle to the substrate supporting the stack of layers making up the read head. The stack is patterned with photoresist to define a rectangular region with front and back long edges aligned parallel to the read head track width. After ion milling in two opposite directions orthogonal to the front and back long edges, the pinned layer width has an extension. The extension makes the width of the pinned layer greater than the stripe height of the free layer after the substrate and stack of layers are lapped. The length of the extension is determined by the angle between the substrate and the ion beam and the thickness of the photoresist.
    Type: Grant
    Filed: March 3, 2005
    Date of Patent: March 25, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Marie-Claire Cyrille, Meng Ding, Elizabeth Ann Dobisz, Kuok San Ho, Scott Arthur MacDonald
  • Patent number: 7345854
    Abstract: A method for fabricating a spin-valve GMR sensor having a reference layer with a magnetic moment that moves in an opposite direction to that of the free layer in the presence of external magnetic field transitions. The reference layer is a part of a three ferromagnetic layer structure, including pinned, intermediate and reference layers, that when the layers are taken pairwise and separated by spacer layers, includes a strongly exchange coupled synthetic ferrimagnetic pinned and intermediate layer pair and a weakly exchange coupled synthetic ferrimagnetic intermediate and reference layer pair. The reference layer, because of its weak coupling to the intermediate layer, has a magnetic moment that is free to move. During sensor operation, the reference layer and free layer move in opposite directions under the influence of external magnetic field transitions The novel three layer structure provides a sensor of increased sensitivity for a given track width.
    Type: Grant
    Filed: July 13, 2004
    Date of Patent: March 18, 2008
    Assignee: Headway Technologies, Inc.
    Inventor: Kenichi Takano
  • Publication number: 20080055789
    Abstract: Provided is a magnetic memory device that uses a current induced switching (CID) method. The magnetic memory device that uses a CID method includes a lower electrode, a magnetic resistance structure that is formed on the lower electrode which comprises a free layer whose widths of two sides are varied, and an upper electrode formed on the magnetic resistance structure.
    Type: Application
    Filed: August 30, 2007
    Publication date: March 6, 2008
    Inventors: Eun-sik Kim, Kook-hyun Sunwoo, Sung-chul Lee
  • Patent number: 7336070
    Abstract: The application provides a magnetic sensor which can suppress an irregularity of a central potential due to a change in a temperature, decrease size of the sensor, and lower the manufacturing cost of the sensor. A magneto-resistive element and fixed resister are provided on an element base and have the same configuration elements. A second magnetic layer and non-magnetic layer in the fixed resistor are reversely laminated on each other in a manner different from the magneto-resistive element, and the second magnetic layer is formed in contact with the first magnetic layer, thereby fixing the magnetization directions of the first magnetic layer and the second magnetic layer in the same direction. In this manner, the irregularity of the temperature coefficient between the magneto-resistive element and the fixed resistor is suppressed, and the irregularity of the central potential due to the change in the temperature is suppressed.
    Type: Grant
    Filed: March 12, 2007
    Date of Patent: February 26, 2008
    Assignee: Alps Electric Co., Inc.
    Inventor: Yoshito Sasaki
  • Patent number: 7333306
    Abstract: A TMR sensor, a CPP GMR sensor and a CCP CPP GMR sensor all include a tri-layered free layer that is of the form CoFe/CoFeB/NiFe, where the atom percentage of Fe can vary between 5% and 90% and the atom percentage of B can vary between 5% and 30%. The sensors also include SyAP pinned layers which, in the case of the GMR sensors include at least one layer of CoFe laminated onto a thin layer of Cu. In the CCP CPP sensor, a layer of oxidized aluminum containing segregated particles of copper is formed between the spacer layer and the free layer. All three configurations exhibit extremely good values of coercivity, areal resistance, GMR ratio and magnetostriction.
    Type: Grant
    Filed: August 23, 2005
    Date of Patent: February 19, 2008
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Kunliang Zhang, Hui-Chuan Wang, Yu-Hsia Chen, Min Li
  • Patent number: 7331100
    Abstract: An improved seed/AFM structure is formed by first depositing a layer of tantalum on the lower shield. A NiCr layer is then deposited on the Ta followed by a layer of IrMn. The latter functions effectively as an AFM for thicknesses in the 40-80 Angstrom range, enabling a reduced shield-to-shield spacing.
    Type: Grant
    Filed: July 7, 2004
    Date of Patent: February 19, 2008
    Assignee: Headway Technologies, Inc.
    Inventors: Min Li, Cheng T. Horng, Cherng Chyi Han, Yue Liu, Yu-Hsia Chen, Ru-Ying Tong
  • Patent number: 7327540
    Abstract: A hard bias layer that forms an abutting junction with a free layer in a GMR element and is comprised of FePtCu or FePtCuX where X is B, C, O, Si, or N is disclosed. The FePtCu layer has a composition of about 45 atomic % Fe, 45 atomic % Pt, and 10 atomic % Cu and does not require a seed layer to achieve an ordered structure. The FePtCu layer is annealed at a temperature of about 280° C. and has an Hc value more than double that of a conventional CoCrPt hard bias layer with a similar thickness. Since the FePtCu hard bias layer adjoins a free layer, it has a higher sensor edge pinning efficiency than a configuration with a CoCrPt layer on a seed layer. The novel hard bias layer is compatible with either a top or bottom spin valve structure in a GMR sensor.
    Type: Grant
    Filed: June 1, 2004
    Date of Patent: February 5, 2008
    Assignee: Headway Technologies, Inc.
    Inventors: Yun-Fei Li, Kunliang Zhang, Chyu-Jiuh Torng
  • Patent number: 7320170
    Abstract: Using a beam of xenon ions together with a suitable mask, a GMR stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the longitudinal bias and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Grant
    Filed: April 20, 2004
    Date of Patent: January 22, 2008
    Assignees: Headway Technologies, Inc., TDK Corporation
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jei-Wei Chang
  • Publication number: 20080008909
    Abstract: A method for manufacturing a magneto-resistance effect element includes: forming a first magnetic layer; forming a first metallic layer, on the first magnetic layer, mainly containing an element selected from the group consisting of Cu, Au, Ag; forming a functional layer, on the first metallic layer, mainly containing an element selected from the group consisting of Si, Hf, Ti, Mo, W, Nb, Mg, Cr and Zr; forming a second metallic layer, on the functional layer, mainly containing Al; treating the second metallic layer by means of oxidizing, nitriding or oxynitiriding so as to form a current confined layer including an insulating layer and a current path with a conductor passing a current through the insulating layer; and forming, on the current confined layer, a second magnetic layer.
    Type: Application
    Filed: May 23, 2007
    Publication date: January 10, 2008
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshihiko Fuji, Hideaki Fukuzawa, Hiromi Yuasa
  • Publication number: 20070291420
    Abstract: An optical processing element has a first face and a second face opposite to the first face. A first processing portion is disposed on the first face and a second processing portion is disposed on the second face. The first processing portion and the second processing portion both have continuous arc patterns. The radius of the arc pattern of the first processing portion is not equal to that of the arc pattern of the second procession portion. The optical processing element processes light source in order to produce even light emission, thereby solving the shortcomings of the prior art.
    Type: Application
    Filed: August 28, 2006
    Publication date: December 20, 2007
    Inventor: Hai-Han Chen
  • Patent number: 7304825
    Abstract: Disclosed is a CCP-CPP-GMR head assembly which has: a CCP-CPP-GMR head that includes at least a current control layer having as a microstructure a plurality of truncated cone electric conductors with axes the same as a current direction and an insulator filling between the plurality of truncated cone electric conductors, and in which a surface on which a larger-area basal plane of the plurality of truncated cone electric conductors is greater in number is a first surface of the current control layer and a surface of an opposite side of the first surface is a second surface of the current control layer; and a sense current source providing the CCP-CPP-GMR head with a sense current that flows from the second surface to the first surface, a magnetic recording/reproducing apparatus having such a head, and a specification method of an appropriate sense current direction of the CCP-CPP-GMR head.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: December 4, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Funayama, Kohichi Tateyama, Masayuki Takagishi
  • Patent number: 7301733
    Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film and a pair of electrode. The magnetoresistance effect film having a first magnetic layer whose direction of magnetization is substantially pinned in one direction; a second magnetic layer whose direction of magnetization changes in response to an external magnetic field; a nonmagnetic intermediate layer located between the first and second magnetic layers; and a film provided in the first magnetic layer, in the second magnetic layer, at a interface between the first magnetic layer and the nonmagnetic intermediate layer, and/or at a interface between the second magnetic layer and the nonmagnetic intermediate layer, the film having a thickness not larger than 3 nanometers, and the film has as least one selected from the group consisting of oxide, nitride, oxinitride, phosphide, and fluoride.
    Type: Grant
    Filed: March 28, 2003
    Date of Patent: November 27, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Hiromi Yuasa, Hiromi Fuke, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 7292414
    Abstract: A disk includes a perpendicular recording disk, a head having a read portion to read information recorded on the perpendicular recording disk, a sensor in the read portion, and a coil structure, coupled to the read portion, to provide bias flux to the sensor. The coil structure may include two coils.
    Type: Grant
    Filed: October 11, 2002
    Date of Patent: November 6, 2007
    Assignee: Maxtor Corporation
    Inventor: Michael Mallary
  • Patent number: 7290324
    Abstract: A magnetic head including a media heating device. Following the fabrication of the heating device, a sacrificial layer of material is deposited to protect the heating device during subsequent process steps. Thereafter, write head components, such as write head induction coils and/or a P1 pole pedestal are fabricated above the heating device, and the sacrificial layer is substantially consumed in protecting the heating device during the aggressive etching and milling steps used to create those components. Further components, including a second magnetic pole are thereafter fabricated to complete the fabrication of the write head portion of the magnetic head. The sacrificial layer may be comprised of alumina, or a material such as NiFe that can act as a seed layer for a subsequent head components such as the P1 pole pedestal.
    Type: Grant
    Filed: September 19, 2005
    Date of Patent: November 6, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Robert E. Fontana, Jr., Jeffrey S. Lille
  • Patent number: 7283334
    Abstract: A magnetic head having a spin valve sensor that is fabricated utilizing an Al2O3, NiMnO, NiFeCr seed layer upon which a typical PtMn spin valve sensor layer structure is subsequently fabricated. The preferred embodiment fabrication process of the NiFeCr layer includes the overdeposition of the layer to a first thickness of from 15 ? to 45 ? followed by the etching back of the seed layer of approximately 5 ? to approximately 15 ? to its desired final thickness of approximately 10 ? to 40 ?. The Cr at. % composition in the NiFeCr layer is preferably from approximately 35 at. % to approximately 46 at. %. The crystal structure of the surface of the etched back NiFeCr layer results in an improved crystal structure to the subsequently fabricated spin valve sensor layers, such that the fabricated spin valve exhibits increased ?R/R and reduced coercivity.
    Type: Grant
    Filed: June 15, 2006
    Date of Patent: October 16, 2007
    Assignee: International Business Machines Corporation
    Inventor: Mustafa Pinarbasi
  • Patent number: 7283328
    Abstract: A thin-film magnetic head includes at least one inductive write head element and at least one read magnetic head element, capable of controlling a spacing between a magnetic recording medium and the at least one magnetic read head element by heating. A gain SG (nm/° C.) of the spacing is greater than a spacing gain threshold SGTHLD (nm/° C.) defined by the following expression: SGLIMT=A*dPTP+B A=1.4642E?02*exp(?6.6769E?05*LRDMF) B=4.9602E?01*exp(?2.0423E?03*LRDMF) where dPTP represents an amount of change in protrusion (nm) of a top end of the at least one inductive write head element and/or the at least one read magnetic head element by heating, and LRDMF represents a line recording density (kFCI) at a frequency half of the maximum recording frequency.
    Type: Grant
    Filed: April 26, 2005
    Date of Patent: October 16, 2007
    Assignee: TDK Corporation
    Inventors: Norikazu Ota, Kenji Inage, Taro Oike
  • Patent number: 7279269
    Abstract: The series resistance of a CPP GMR stack can be reduced by shaping it into a small upper, on a somewhat larger, lower part. Because of the sub-micron dimensions involved, good alignment between these is normally difficult to achieve. The present invention discloses a self-alignment process based on first laying down a mask that will determine the shape of the top part. Ion beam etching is then initiated, the ion beam being initially applied from one side only at an angle to the surface normal. During etching, all material on the near side of the mask gets etched but, on the far side, only material that is outside the mask's shadow gets removed so, depending on the beam's angle, the size of the lower part is controlled and the upper part is precisely centrally aligned above it.
    Type: Grant
    Filed: December 12, 2003
    Date of Patent: October 9, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Jeiwei Chang, Stuart Kao, Chao Peng Chen, Chunping Luo, Kochan Ju, Min Li
  • Patent number: 7274542
    Abstract: A magnetic sensor includes a spacer having at least a nonmagnetic metal layer inserted between the upper shield layer and the longitudinal bias layers or between the upper shield layer and the longitudinal bias layers plus the magnetoresistive film, the shortest distance between the longitudinal bias layers and the free layer of the magnetoresistive film is set smaller than the shortest distance between the longitudinal bias layers and the upper shield layer, and this arrangement ensures that the amount of magnetic flux entering the magnetoresistive film from the longitudinal bias layers is larger than that absorbed by the upper shield layer, thus realizing a magnetic sensor whose Barkhausen noise is suppressed.
    Type: Grant
    Filed: February 5, 2003
    Date of Patent: September 25, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Taku Shintani, Katsuro Watanabe, Masahiko Hatatani, Kikuo Kusukawa
  • Publication number: 20070217077
    Abstract: A manufacturing method of a thin-film magnetic head in which a magneto-sensitive portion is formed in a position where the width along the track-width direction is sufficiently small and a bias field from a bias means can be sufficiently received, and the influence of reattachments on reading output is avoided. The manufacturing method comprises steps of: forming an MR multilayer film comprising a foundation layer; a magneto-sensitive portion; and a cap layer of a material having an ion beam etching rate lower than that of a material of a free layer of the magneto-sensitive portion; and forming an MR effect multilayer by applying ion beam etching to the MR effect multilayer film by using a resist pattern as a mask in such a manner that an end point of the ion beam etching is below an upper surface of the lower electrode layer.
    Type: Application
    Filed: March 9, 2007
    Publication date: September 20, 2007
    Applicant: TDK Corporation
    Inventors: Takayasu Kanaya, Kazuki Sato, Daisuke Miyauchi
  • Patent number: 7253995
    Abstract: A magnetic head includes a first electrode layer, a first ferromagnetic electrode pair that is electrically connected to the first electrode layer, and a second ferromagnetic electrode pair that intersects with a current which flows between the first ferromagnetic electrode pairs and is electrically connected with the first electrode layer. The current is allowed to flow between the first ferromagnetic electrode pair through the first electrode layer to accumulate spin electrons in the first electrode layer. A direction of magnetization of the fourth ferromagnetic electrode layer changes upon application of an external magnetic field. The second ferromagnetic electrode pair is so arranged as to intersect with the current that flows between the first ferromagnetic electrode pair, to increase a rate of change in the output signal of the in-plane spin accumulation effect.
    Type: Grant
    Filed: September 1, 2004
    Date of Patent: August 7, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Hiromasa Takahashi, Kenchi Ito
  • Patent number: 7246427
    Abstract: Biasing schemes used for CIP GMR devices were previously thought to be impractical for CPP devices due to current shunting by the abutted hard magnets. In the present invention the CPP stripe is a narrow conductor directly above the free layer. The resistivity of the latter is made to be relatively high so the sensing current diverges very little as it passes through it. This makes it possible to use abutted hard magnets for longitudinal bias with virtually no loss of sensing current due to shunting by the magnets.
    Type: Grant
    Filed: February 3, 2004
    Date of Patent: July 24, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Yimin Guo, Li-Yan Zhu