With Defined Structural Feature Patents (Class 428/811.5)
  • Patent number: 8057925
    Abstract: A dual spin filter that minimizes spin-transfer magnetization switching current (Jc) while achieving a high dR/R in STT-RAM devices is disclosed. The bottom spin valve has a MgO tunnel barrier layer formed with a natural oxidation process to achieve low RA, a CoFe/Ru/CoFeB—CoFe pinned layer, and a CoFeB/FeSiO/CoFeB composite free layer with a middle nanocurrent channel (NCC) layer to minimize Jc0. The NCC layer may have be a composite wherein conductive M(Si) grains are magnetically coupled with adjacent ferromagnetic layers and are formed in an oxide, nitride, or oxynitride insulator matrix. The upper spin valve has a Cu spacer to lower the free layer damping constant. A high annealing temperature of 360° C. is used to increase the MR ratio above 100%. A Jc0 of less than 1×106 A/cm2 is expected based on quasistatic measurements of a MTJ with a similar MgO tunnel barrier and composite free layer.
    Type: Grant
    Filed: March 27, 2008
    Date of Patent: November 15, 2011
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong
  • Patent number: 8048686
    Abstract: The invention relates to a method for producing a device comprising magnetic blocks magnetized in different directions, comprising steps of: a) forming, in a stack of one or more layers of at least one antiferromagnetic material and one or more layers of at least one ferromagnetic material resting on a substrate, at least one first block and at least one second block, said blocks being longilineal and separate and extending respectively in a first main direction and in a second main direction, the first and the second main direction forming between them a first non-zero angle ?, b) annealing said blocks at a temperature greater than the ordering temperature of said antiferromagnetic material or than the blocking temperature or than the Néel temperature of said antiferromagnetic material.
    Type: Grant
    Filed: December 17, 2010
    Date of Patent: November 1, 2011
    Assignee: Commissariat a l'Energie Atomic
    Inventor: Olivier Redon
  • Patent number: 8043732
    Abstract: Magnetic tunnel junction cells and methods of making magnetic tunnel junction cells that include a radially protective layer extending proximate at least the ferromagnetic free layer of the cell. The radially protective layer can be specifically chosen in thickness, deposition method, material composition, and/or extent along the cell layers to enhance the effective magnetic properties of the free layer, including the effective coercivity, effective magnetic anisotropy, effective dispersion in magnetic moment, or effective spin polarization.
    Type: Grant
    Filed: November 11, 2008
    Date of Patent: October 25, 2011
    Assignee: Seagate Technology LLC
    Inventors: Paul E. Anderson, Song S. Xue
  • Patent number: 8036024
    Abstract: In a ferromagnetic tunnel junction element, a recording layer is in a circular shape, which can suppress an increase in magnetization switching field due to miniaturization of the element. Further, the recording layer includes a first ferromagnetic layer, a first non-magnetic layer, a second ferromagnetic layer, a second non-magnetic layer, and a third ferromagnetic layer successively stacked. The first and second ferromagnetic layers, and the second and third ferromagnetic layers are coupled antiparallel to each other, so that it is possible to control the magnetization distribution of the recording layer in an approximately single direction.
    Type: Grant
    Filed: May 30, 2006
    Date of Patent: October 11, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Takashi Takenaga, Takeharu Kuroiwa, Hiroshi Kobayashi, Sadeh Beysen
  • Patent number: 7939188
    Abstract: A magnetic stack having a free layer having a switchable magnetization orientation, a reference layer having a pinned magnetization orientation, and a barrier layer therebetween. The stack includes an annular antiferromagnetic pinning layer electrically isolated from the free layer and in physical contact with the reference layer. In some embodiments, the reference layer is larger than the free layer.
    Type: Grant
    Filed: July 13, 2009
    Date of Patent: May 10, 2011
    Assignee: Seagate Technology LLC
    Inventors: Haiwen Xi, Antoine Khoueir, Brian Lee, Pat Ryan, Michael Tang, Insik Jin, Paul E. Anderson
  • Patent number: 7935435
    Abstract: A magnetic tunnel junction cell having a free layer, a ferromagnetic pinned layer, and a barrier layer therebetween. The free layer has a central ferromagnetic portion and a stabilizing portion radially proximate the central ferromagnetic portion. The construction can be used for both in-plane magnetic memory cells where the magnetization orientation of the magnetic layer is in the stack film plane and out-of-plane magnetic memory cells where the magnetization orientation of the magnetic layer is out of the stack film plane, e.g., perpendicular to the stack plane.
    Type: Grant
    Filed: September 19, 2008
    Date of Patent: May 3, 2011
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi
  • Patent number: 7931976
    Abstract: A magnetic recording element includes a multilayer having a surface and a pair of electrodes. The multilayer has a first magnetic fixed layer whose magnetization is substantially fixed in a first direction substantially perpendicular to the surface. The multilayer also has a second magnetic fixed layer whose magnetization is substantially fixed in a second direction opposite to the first direction substantially perpendicular to the surface. A third magnetic layer is provided between the first and second magnetic layers. The direction of magnetization of the third ferromagnetic layer is variable. A first intermediate layer is provided between the first and the third magnetic layers. A second intermediate layer is provided between the second and the third magnetic layers. The pair of electrodes is capable of supplying an electric current flowing in a direction substantially perpendicular to the surface to the multilayer.
    Type: Grant
    Filed: October 3, 2008
    Date of Patent: April 26, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuichi Ohsawa, Shiho Nakamura, Hirofumi Morise, Satoshi Yanagi, Daisuke Saida
  • Patent number: 7914915
    Abstract: A highly charged ion modified device is provided that includes a first metal layer or layers deposited on a substrate and an insulator layer, deposited on the first metal layer, including a plurality of holes therein produced by irradiation thereof with highly charged ions. The metal of a further metal layer, deposited on the insulator layer, fills the plurality of holes in the insulator layer.
    Type: Grant
    Filed: February 25, 2008
    Date of Patent: March 29, 2011
    Assignee: The United States of America as represented by the Secretary of the Commerce, The National Institutes of Standards and Technology
    Inventors: Joshua M. Pomeroy, Holger Grube, Andrew Perrella, Fern Slew, legal representative
  • Patent number: 7755929
    Abstract: First and second tunnel junctions having a common electrode composed of a nonmagnetic conductor and each of which has a counterelectrode composed of a ferromagnet are spaced apart from each other by a distance that is shorter than a spin diffusion length of the nonmagnetic conductor. The first tunnel junction injects spin from the ferromagnet into the nonmagnetic conductor and the second tunnel junction detects, between the ferromagnetic metal and the nonmagnetic conductor, a voltage that accompanies spin injection of the first tunnel junction. The nonmagnetic conductor may be a semiconductor or semimetal that is lower in carrier density than a metal. The common electrode alternatively may be composed of a superconductor. A spin injection device thus provided can exhibit a large signal voltage with a low current and under low magnetic field and can be miniaturized in device size.
    Type: Grant
    Filed: November 20, 2003
    Date of Patent: July 13, 2010
    Assignee: Japan Science and Technology Agency
    Inventors: Kouichiro Inomata, Sadamichi Maekawa, Saburo Takahashi
  • Patent number: 7684161
    Abstract: A synthetic antiferromagnet (SAF) structure includes a first ferromagnetic layer, a first insertion layer, a coupling layer, a second insertion layer, and a second ferromagnetic layer. The insertion layers comprise materials selected such that SAF exhibits reduced temperature dependence of antiferromagnetic coupling strength. The insertion layers may include CoFe or CoFeX alloys. The thickness of the insertion layers is selected such that they do not increase the uniaxial anisotropy or deteriorate any other properties.
    Type: Grant
    Filed: April 18, 2006
    Date of Patent: March 23, 2010
    Assignee: Everspin Technologies, Inc.
    Inventors: Srinivas V. Pietambaram, Renu W. Dave, Jon M. Slaughter, JiJun Sun
  • Patent number: 7678475
    Abstract: Spin-torque devices are based on a combination of giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) effects. The basic structure has various applications, including amplifiers, oscillators, and diodes. For example, if the low-magnetoresistance (GMR) contact is biased below a critical value, the device may function as a microwave-frequency selective amplifier. If the GMR contact is biased above the critical value, the device may function as a microwave oscillator. A plurality of low- and high-magnetoresistance contact pairs may be induced to oscillate in a phase-locked regime, thereby multiplying output power. The frequency of operation of these devices will be tunable by the external magnetic field, as well as by the direct bias current, in the frequency range between 10 and 100 GHz. The devices do not use semiconductor materials and are expected to be exceptionally radiation-hard, thereby finding application in military nanoelectronics.
    Type: Grant
    Filed: May 5, 2006
    Date of Patent: March 16, 2010
    Inventors: Andrei N. Slavin, Ilya N. Krivorotov
  • Patent number: 7652852
    Abstract: A method of production of a magnetoresistance effect device is able to prevent or minimize a drop in the MR ratio and maintain the high performance of the magnetoresistance effect device even if forming an oxide layer as a surface-most layer constituting a protective layer by the oxidation process inevitably included in the process of production of microprocessing by dry etching performed in a vacuum. Two mask layers used for microprocessing are doubly piled up. This method of production of a magnetoresistivity effect device including a magnetic multilayer film including at least two magnetic layers includes a step of providing under a first mask material that is a nonorganic material a second mask material able to react with other atoms to form a conductive substance, and a device made according to the method.
    Type: Grant
    Filed: August 11, 2005
    Date of Patent: January 26, 2010
    Assignee: Canon Anelva Corporation
    Inventors: Hiroki Maehara, Tomoaki Osada, Mihoko Doi, Koji Tsunekawa, Naoki Watanabe
  • Patent number: 7606010
    Abstract: ZnMg oxide tunnel barriers are grown which, when sandwiched between ferri- or ferromagnetic layers, form magnetic tunnel junctions exhibiting high tunneling magnetoresistance (TMR). The TMR may be increased by annealing the magnetic tunnel junctions. The zinc-magnesium oxide tunnel barriers may be incorporated into a variety of other devices, such as magnetic tunneling transistors and spin injector devices. The ZnMg oxide tunnel barriers are grown by first depositing a zinc and/or magnesium layer onto an underlying substrate in oxygen-poor (or oxygen-free) conditions, and subsequently depositing zinc and/or magnesium onto this layer in the presence of reactive oxygen.
    Type: Grant
    Filed: July 12, 2007
    Date of Patent: October 20, 2009
    Assignee: International Business Machines Corporation
    Inventor: Stuart Stephen Papworth Parkin
  • Patent number: 7547480
    Abstract: An integrated circuit device is provided which comprises a substrate, a conductive line configured to experience a pressure, and a magnetic tunnel junction (“MTJ”) core formed between the substrate and the current line. The conductive line is configured to move in response to the pressure, and carries a current which generates a magnetic field. The MTJ core has a resistance value which varies based on the magnetic field. The resistance of the MTJ core therefore varies with respect to changes in the pressure. The MTJ core is configured to produce an electrical output signal which varies as a function of the pressure.
    Type: Grant
    Filed: October 28, 2005
    Date of Patent: June 16, 2009
    Assignee: Everspin Technologies, Inc.
    Inventors: Young Sir Chung, Robert W. Baird, Bradley N. Engel
  • Patent number: 7514160
    Abstract: By varying only the thickness of a known material having superior magnetic characteristics to increase spin polarization without changing the chemical composition, a tunnel magnetoresistive element capable of producing a larger magnetoresistive effect is provided. The tunnel magnetoresistive element includes an underlayer (nonmagnetic or antiferromagnetic metal film); an ultrathin ferromagnetic layer disposed on the underlayer; an insulating layer disposed on the ultrathin ferromagnetic layer; and a ferromagnetic electrode disposed on the insulating layer.
    Type: Grant
    Filed: February 12, 2007
    Date of Patent: April 7, 2009
    Assignees: National Institute of Advanced Industrial Science and Technology, Japan Science and Technology Agency
    Inventors: Taro Nagahama, Shinji Yuasa, Yoshishige Suzuki
  • Patent number: 7494724
    Abstract: A method of manufacturing a magnetoresistance effect element includes forming an insulating layer on a first ferromagnetic layer, forming an aperture reaching the first ferromagnetic layer by thrusting a needle from the top surface of the insulating layer, and depositing a ferromagnetic material to form a second ferromagnetic layer overlying the insulating layer which buries the aperture. The aperture can have an opening width not larger than 20 nm. A current flowing between the first ferromagnetic layer and the needle can be monitored, and thrusting of the needle an be interrupted when the current reaches a predetermined value.
    Type: Grant
    Filed: July 3, 2007
    Date of Patent: February 24, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi
  • Patent number: 7446985
    Abstract: A magnetic head and magnetic storage system containing such a head, the head including a free layer and a layer of metal oxide substantially epitaxially formed relative to the free layer. Preferably, the layer of metal oxide is a crystalline structure, and is of ZnO.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: November 4, 2008
    Assignees: Agency for Science Technology and Research, Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Wen-yaung Lee, Jinshan Li, Kebin Li, Yihong Wu
  • Patent number: 7390584
    Abstract: A ferromagnetic thin-film based magnetic device with internal film coupling compensation including a nonmagnetic material intermediate layer with an initial thin-film of an anisotropic ferromagnetic material on one side. A compensation thin-film of an anisotropic ferromagnetic material is provided on the opposite side with an antiparallel coupling layer thereon and a subsequent thin-film of an anisotropic ferromagnetic material on the antiparallel coupling layer with the compensation thin-film being less thick than the subsequent thin-film. A antiferromagnetic layer can be supported by the layers on either side of the intermediate layer.
    Type: Grant
    Filed: March 21, 2003
    Date of Patent: June 24, 2008
    Assignee: NVE Corporation
    Inventors: James M. Daughton, Dexin Wang
  • Patent number: 7381480
    Abstract: A magnetic recording element includes a fixed layer having first and second surfacesm, a recording layer having third and fourth surfaces and being essentially made of a ferromagnetic material having first and second atomic potentials for the majority-spin band electrons and the minority-spin band electrons, a spacer layer being arranged between the fixed and recording layers and being in contact with the second and third surfaces, a cap layer having fifth and sixth surfaces, being essentially made of a nonmagnetic material having a third atomic potential less than an intermediate value between the first and second atomic potentials, and having a thickness of not more than 3 nm, the fifth surface being in contact with the fourth surface, and a reflecting layer being in contact with the sixth surface and being essentially made of a nonmagnetic material having a forth atomic potential different from the third atomic potential.
    Type: Grant
    Filed: April 29, 2005
    Date of Patent: June 3, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Nakamura, Shigeru Haneda, Hirofumi Morise
  • Patent number: 7369373
    Abstract: A current perpendicular to plane magnetorestive sensor having an improved in stack biasing. An amorphous layer breaks the structure allowing a desire crystolographic structure in an in stack bias layer that provides greatly increased coercivity (Hc) in the bias layer.
    Type: Grant
    Filed: April 26, 2004
    Date of Patent: May 6, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7362546
    Abstract: A fixed magnetic layer contains a first magnetic layer formed on a non-magnetic metal layer. The non-magnetic metal layer is composed of an X—Mn alloy (where X is selected from Pt, Pd, Ir, Rh, Ru, Os, Ni, and Fe). While atoms forming the first magnetic layer and atoms forming the non-magnetic metal layer are being aligned with each other, strains are generated in the individual crystal structures. By generating the strain in the crystal structure of the first magnetic layer, the magnetostriction constant ? is increased. As a result, a magnetic sensor having a large magnetoelastic effect can be provided.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: April 22, 2008
    Assignee: Alps Electric Co., Ltd
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide, Masahiro Oshima
  • Patent number: 7300712
    Abstract: In a magnetic sensor (1) including a substrate (10) having a magnetism-sensitive element (11) formed thereon, a hard membrane (14) is formed on the outermost surface, an organic film (13) to relieve the stress caused by the hard membrane (14) is formed under the hard membrane (14), and an inorganic film (12) to relieve the stress caused by the organic film (13) is formed between the organic film (13) and magnetism-sensitive element (11). Also, an intermediate film formed from an element having a large force of bonding to carbon may be formed between the organic film (13) and hard membrane (14). Thus, the magnetic sensor (MR sensor, for example) can be protected against an external shock.
    Type: Grant
    Filed: October 20, 2003
    Date of Patent: November 27, 2007
    Assignee: Sony Manufacturing Systems Corporation
    Inventors: Masaaki Kusumi, Mitsuru Ohno, Michio Okano, Hideki Nakamori, Touru Sumiya, Akitaka Tsunogae, Tomoyuki Nakada, Teruyuki Miura, Yoshihiko Ohkawara
  • Patent number: 7300711
    Abstract: Magnetic material, which is not normally bcc-structured under ambient conditions, is induced into becoming bcc as a result of its proximity to a suitable templating material, such as a bcc-structured underlayer that is in contact with the magnetic material. The magnetic material, in combination with a tunnel barrier and other elements, forms a magnetic tunneling device, such as a magnetic tunnel junction that may have a tunneling magnetoresistance of 100% or more. Suitable tunnel barriers include MgO and Mg—ZnO, and the magnetic material may be Co. The templating material may include such elements as V, Cr, Nb, Mo, and W, or the tunnel barrier MgO may itself serve as the templating material.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: November 27, 2007
    Assignee: International Business Machines Corporation
    Inventor: Stuart Stephen P. Parkin
  • Patent number: 7289303
    Abstract: Magnetoresistive (MR) sensors are disclosed having mechanisms for reducing edge effects such as Barkhausen noise. The sensors include a pinned layer and a free layer with an exchange coupling layer adjoining the free layer, and a ferromagnetic layer having a fixed magnetic moment adjoining the exchange coupling layer. The exchange coupling layer and ferromagnetic layer form a synthetic antiferromagnetic structure with part of the free layer, providing bias that reduces magnetic instabilities at edges of the free layer. Such synthetic antiferromagnetic structures can provide a stronger bias than conventional antiferromagnetic layers, as well as a more exactly defined track width than conventional hard magnetic bias layers. The synthetic antiferromagnetic structures can also provide protection for the free layer during processing, in contrast with the trimming of conventional antiferromagnetic layers that exposes if not removes part of the free layer.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: October 30, 2007
    Assignee: Western Digital (Fremont), LLC
    Inventors: Kyusik Sin, Ningjia Zhu, Yingjian Chen
  • Patent number: 7280320
    Abstract: A lower shield layer is formed by being embedded in a first recess formed in an under layer. Accordingly, the distance between the lower shield layer and a slider can be reduced. Also, a second metal layer is formed from above a gap layer covering an electrode extracting layer over above the under layer hindwards therefrom. Accordingly, the second metal layer can be brought closer to the slider side than an upper shield layer. Consequently, the thermal dissipation effects of the thin-film magnetic head can be improved.
    Type: Grant
    Filed: March 5, 2004
    Date of Patent: October 9, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kiyoshi Sato, Hideki Gochou, Hisayuki Yazawa
  • Patent number: 7265950
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer (1), insulating layer (3) overlying the first ferromagnetic layer, and second ferromagnetic layer (2) overlying the insulating layer. The insulating layer has formed a through hole (A) having an opening width not larger than 20 nm, and the first and second ferromagnetic layers are connected to each other via the through hole.
    Type: Grant
    Filed: September 8, 2004
    Date of Patent: September 4, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi
  • Patent number: 7248445
    Abstract: A magnetic sensing element includes a composite film, a lower shield layer, and a lower electrode layer and an upper electrode layer for supplying a current perpendicular to the composite film. The composite film has an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic layer, and a free magnetic layer. The composite film has a top face and two side faces in a track width direction. Each of the two side faces has a bent position. The angle defined by the side face below the bent position and the top face is larger than the angle defined by the side face above the bent position and the top face. The bent portion preferably lies on the lower electrode layer or the lower shield layer.
    Type: Grant
    Filed: September 11, 2002
    Date of Patent: July 24, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventor: Yoshihiro Nishiyama
  • Patent number: 7241514
    Abstract: A magneto-resistive device is provided for contributing to a higher MR ratio and a reduced cleaning time for cleaning the surface of a cap layer. In the magneto-resistive device, a cap layer which serves as a protection layer is formed on a free layer which is the topmost layer of a magneto-resistive layer constituting a TMR devise. An upper electrode which is additionally used as an upper magnetic shield is electrically connected to the free layer through an upper metal layer. The cap layer comprised of a two-layer film made up of a conductive layer closer to the free layer and a topmost conductive layer. The conductive layer closer to the free layer is made of a material having higher oxygen bond energy than Ru, such as Zr, Hf, or the like. The topmost conductive layer is made of a material having lower oxygen bond energy, such as a noble metal or the like.
    Type: Grant
    Filed: July 1, 2004
    Date of Patent: July 10, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Takumi Uesugi, Satoshi Miura, Norio Takahashi
  • Patent number: 7229706
    Abstract: The present invention provides a magnetic detecting element capable of increasing a difference between the ease of a conduction electron flow in a low-resistance state and the ease of a conduction electron flow in a high-resistance state to increase a resistance change ?R. In the magnetic detecting element, a free magnetic layer or a pinned magnetic layer has a synthetic ferromagnetic structure including a first free magnetic sub-layer or a first pinned magnetic sub-layer containing a magnetic material having a positive ? value, and a second magnetic sub-layer or a second pinned magnetic sub-layer containing a magnetic material having a negative ? value. The ? value is characteristics of a magnetic material satisfying the relationship ??/??=(1+?)/(1??)(?1???1)(wherein ?? represents resistivity for minority conduction electrons, and ?? represents resistivity for majority conduction electrons).
    Type: Grant
    Filed: January 12, 2004
    Date of Patent: June 12, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7223485
    Abstract: A magnetoresistive device includes a magnetization pinned layer, a magnetization free layer, a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer, and electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer. At least one of the magnetization pinned layer and the magnetization free layer is substantially formed of a binary or ternary alloy represented by the formula FeaCobNic (where a+b+c=100 at %, and a?75 at %, b?75 at %, and c?63 at %), or formed of an alloy having a body-centered cubic crystal structure.
    Type: Grant
    Filed: March 7, 2005
    Date of Patent: May 29, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 7220499
    Abstract: A CPP giant magnetoresistive head includes lower and upper shield layers with a predetermined distance therebetween, and a giant magnetoresistive element (GMR) including pinned and free magnetic layers disposed between the upper and lower shield layers with a nonmagnetic layer interposed between the pinned and free magnetic layers. A current flows perpendicularly to the film plane of the GMR. The magnetoresistive head further includes an antiferromagnetic layer (an insulating AF of Ni—O or ?-Fe2O3) provided in the rear of the GMR in a height direction to make contact with the upper or lower surface of a rear portion of the pinned magnetic layer which extends in the height direction, and an exchange coupling magnetic field is produced at the interface with the upper or lower surface, so that the magnetization direction of the pinned magnetic layer is pinned by the exchange coupling magnetic field in the height direction.
    Type: Grant
    Filed: April 13, 2004
    Date of Patent: May 22, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Yoshihiro Nishiyama, Yosuke Ide, Eiji Umetsu, Naoya Hasegawa, Yasuo Hayakawa
  • Patent number: 7218487
    Abstract: An exchange coupling film including an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer so as to generate an exchange coupling magnetic field is provided. A PtMn alloy is used as the material of the antiferromagnetic layer. Crystal planes of the antiferromagnetic layer and the ferromagnetic layer preferentially aligned parallel to the interface are crystallographically identical and crystallographically identical axes lying in these crystal planes are oriented, at least partly, in different directions between the antiferromagnetic layer and the ferromagnetic layer. Thus, a proper order transformation occurs in the antiferromagnetic layer as a result of heat treatment and an increased exchange coupling magnetic field can be obtained.
    Type: Grant
    Filed: April 24, 2006
    Date of Patent: May 15, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7196879
    Abstract: A PtMn alloy film known as an antiferromagnetic material having excellent corrosion resistance is used for an antiferromagnetic layer. However, an exchange coupling magnetic field is decreased depending upon the conditions of crystal grain boundaries. Therefore, in the present invention, the crystal grain boundaries formed in an antiferromagnetic layer (PtMn alloy film) and the crystal grain boundaries formed in a ferromagnetic layer are made discontinuous in at least a portion of the interface between both layers. As a result, the antiferromagnetic layer can be appropriately transformed to an ordered lattice by heat treatment to obtain a larger exchange coupling magnetic field than a conventional element.
    Type: Grant
    Filed: December 16, 2005
    Date of Patent: March 27, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7186470
    Abstract: A magnetic head that uses a thick AP coupling layer in an AP-tab structure. The head includes a free layer having an active area and tab regions on opposite sides of the active area. An antiparallel (AP) coupling layer is formed above the free layer. In one embodiment, the AP coupling layer has a thickness of 15 ? or more. In another embodiment, the AP coupling layer is formed of Ir, and preferably has a thickness of 15 ? or more. A bias layer is formed above each of the tab portions of the free layer, magnetic moments of the tab regions of the free layer being pinned antiparallel to the magnetic moments of the bias layers.
    Type: Grant
    Filed: February 11, 2004
    Date of Patent: March 6, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Stefan Maat
  • Patent number: 7180716
    Abstract: A method for fabricating a stitched CPP synthetic spin-valve sensor with in-stack stabilization of its free layer. The method can also be applied to the formation of a stitched tunneling magnetoresistive sensor. The free layer is strongly stabilized by magnetostatic coupling through the use of a longitudinal biasing formation that includes a ferromagnetic layer, denoted LBL, within the pillar portion of the sensor and a synthetic exchange coupled tri-layer within the stitched portion of the sensor. The tri-layer consists of two ferromagnetic layers, FM1 and FM2 separated by a coupling layer and magnetized longitudinally in antiparallel directions. A criterion for the magnetic thicknesses of the layers: [t(LBL)+t(FM1)]/t(FM2)=70/90 angstroms of CoFe insures a strong exchange coupling. The magnetization of the tri-layer is done in a low field anneal that does not disturb the previous magnetization of the ferromagnetic free layer.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: February 20, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Min Li, Youfeng Zheng, Kunliang Zhang, Simon Liao, Kochan Ju
  • Patent number: 7163755
    Abstract: The present invention provides a vertical current-type magneto-resistive element. The element includes an intermediate layer and a pair of magnetic layers sandwiching the intermediate layer, and at least one of a free magnetic layer and a pinned magnetic layer is a multilayer film including at least one non-magnetic layer and magnetic layers sandwiching the non-magnetic layer. The element area defined by the area of the intermediate layer through which current flows perpendicular to the film is not larger than 1000 ?m2.
    Type: Grant
    Filed: May 17, 2004
    Date of Patent: January 16, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Patent number: 7141314
    Abstract: A current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) sensor of the synthetic spin valve type and its method of formation are disclosed, the sensor including a novel laminated free layer having ultra-thin (less than 3 angstroms thickness) laminas of Fe50 Co50 (or any iron rich alloy of the form CoxFe1?x with x between 0.25 and 0.75) interspersed with thicker layers of Co90Fe10 and Cu spacer layers to produce a free layer with good coercivity, a coefficient of magnetostriction that can be varied between positive and negative values and a high GMR ratio, due to enhancement of the bulk scattering coefficient by the laminas. The configuration of the lamina and layers in periodic groupings allow the coefficient of magnetostriction to be finely adjusted and the coercivity and GMR ratio to be optimized. The sensor performance can be further improved by including layers of Cu and Fe50Co50 in the synthetic antiferromagnetic pinned layer.
    Type: Grant
    Filed: February 25, 2004
    Date of Patent: November 28, 2006
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Min Li, Rachid Sbiaa, Simon Liao, Yue Liu
  • Patent number: 7118814
    Abstract: An apparatus and method for step-stabilization of giant magnetoresistive (GMR) based read heads are provided. With the apparatus and method, gratings or periodic structures are generated in the underlayer of the magnetoresistive (MR) sensor stack and the edges, or “steps”, in these structures are the magnetically active features. These “steps” are oriented approximately parallel to the desired bias direction and provide a restoring force towards the bias direction for any perturbations, whether intrinsic or extrinsic. In the case of a GMR sensor, where the easy axis is parallel to the permanent magnet set direction, these stabilizer steps are oriented parallel to the magnetization direction of the permanent magnets.
    Type: Grant
    Filed: March 2, 2004
    Date of Patent: October 10, 2006
    Assignee: Storage Technology Corporation
    Inventors: Carl Stephen Arnold, Edward Virgil Denison, John P. Nibarger, Carl A. Helms
  • Patent number: 7094480
    Abstract: The invention relates to magnetic field sensors in which magnetoresistance is used as the physical phenomenon for detecting and measuring the magnetic field. It consists in producing a stack comprising a first ferromagnetic layer (101), an insulating layer (103), a second ferromagnetic layer (102) and an antiferromagnetic layer (104). The two ferromagnetic layers exhibit crossed magnetic anisotropies and form with the insulating layer a tunnel junction. The anisotropy of the first layer is obtained from the shape energy of the substrate on which this first layer rests and which is slightly misoriented with respect thereto. The anisotropy of the second layer is obtained by the action of the antiferromagnetic layer.
    Type: Grant
    Filed: April 27, 2001
    Date of Patent: August 22, 2006
    Assignee: Thales
    Inventors: Frederic Nguyen Van Dau, Henri Jaffres, Daniel Lacour
  • Patent number: 7045224
    Abstract: The present invention provides a magnetic detecting element including a pinned magnetic layer and a first antiferromagnetic layer which constitutes an exchange coupling film and the structures of which are optimized for properly pinning magnetization of the pinned magnetic layer, improving reproduction output and properly complying with a narrower gap, and a method of manufacturing the magnetic detecting element. The pinned magnetic layer has a synthetic ferrimagnetic structure, and the first antiferromagnetic layer has a predetermined space C formed at the center in the track width direction to produce exchange coupling magnetic fields only between the first antiferromagnetic layer and both side portions of a first magnetic layer of the pinned magnetic layer. Therefore, the magnetization of the pinned magnetic layer can be pinned, and an improvement in reproduction output and gap narrowing can be realized.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: May 16, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide
  • Patent number: 7029771
    Abstract: An intermediate region is formed at a central portion of an element in a track width direction, and an antiferromagnetic layer is not provided at the intermediate region. Accordingly, a sense current can be prevented from being shunted to the intermediate region, and as a result, improvement in reproduction output and strength against magnetic electrostatic damage can be realized. In addition, since the thickness of the central portion of the element is decreased, trend toward narrower gap can be realized. Furthermore, since the direction of magnetization of a free magnetic layer is oriented in the track width direction by shape anisotropy, means for orienting the magnetization is not necessary, and hence the structure and manufacturing method of the element can be simplified.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: April 18, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide
  • Patent number: 7029770
    Abstract: An exchange-coupled film has a ferromagnetic layer sandwich comprising a first ferromagnetic layer containing a ferromagnetic material of the body-centered cubic structure and a pair of second ferromagnetic layers containing a ferromagnetic material of the face-centered cubic structure and formed on respective sides of the first ferromagnetic layer; and an antiferromagnetic layer containing a disordered alloy and formed on one of the second ferromagnetic layers. It yields sufficient exchange coupling energy even in smaller thickness of the antiferromagnetic layer than before, whereby it becomes feasible to decrease the thickness of the exchange-coupled film.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: April 18, 2006
    Assignee: TDK Corporation
    Inventors: Koji Shimazawa, Yoshihiro Tsuchiya, Koichi Terunuma
  • Patent number: 7008702
    Abstract: A magnetoresistance effect element includes a nonmagnetic spacer layer, first and second ferromagnetic layer separated by the nonmagnetic spacer layer, and a nonmagnetic conductivity layer. The first ferromagnetic layer has a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field. The second ferromagnetic layer has first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films. The magnetization of the first ferromagnetic layer freely rotates in a magnetic field signal. The nonmagnetic conductivity layer is disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic high-conductivity layer and the nonmagnetic spacer layer. The first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: March 7, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
  • Patent number: 7008703
    Abstract: A magnetic detecting element has a multilayer laminate including a first free magnetic layer. A second antiferromagnetic layer is disposed on each side surface of the multilayer laminate in the track width direction. A second free magnetic layer is disposed from the upper surface of the second antiferromagnetic layer to the upper surface of the first free magnetic layer. Thus, the shield distance in the central portion of the element can be prevented from increasing, and the insulation between a shield layer and an electrode layer is enhanced.
    Type: Grant
    Filed: July 1, 2003
    Date of Patent: March 7, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Patent number: 7005201
    Abstract: In a magnetic detecting element, second ferromagnetic layers are deposited on respective second antiferromagnetic layers. The magnetization direction of the second ferromagnetic layers is antiparallel to that of first ferromagnetic layers. A static magnetic field generated by a surface magnetic charge at the internal side surfaces of the first ferromagnetic layers is absorbed by the second ferromagnetic layers. Thus, it becomes hard that the static magnetic field from the first ferromagnetic layers enters the central portion of a free magnetic layer. Consequently, the central portion of the free magnetic layer can maintain its single magnetic domain state, and, thus, the hysteresis can be reduced and the Barkhausen noise is suppressed.
    Type: Grant
    Filed: September 5, 2003
    Date of Patent: February 28, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Patent number: 7001680
    Abstract: The present disclosure describes magnetic tunnel junction (MTJ) devices and systems involving the use of diffusion components selected to alter the device properties. The diffusion components migrate from one layer of the MTJ structure to the tunneling barrier layer. Incorporation of the migrated components at the barrier layer adjusts the properties of the MTJ device.
    Type: Grant
    Filed: July 29, 2003
    Date of Patent: February 21, 2006
    Inventor: Hardayal Singh Gill
  • Patent number: 6979500
    Abstract: A magnetic sensing element is provided, in which magnetization of a free magnetic layer is likely to fluctuate when the track width is further reduced, and thereby, the magnetic field detection sensitivity can be improved. A second free magnetic layer having a dimension W2 in the track-width direction is laminated on a first free magnetic layer having a dimension W1 in the track-width direction while the dimension W2 is larger than the dimension W1. The film thickness ta of the free magnetic layer in the track-width region A is made larger than the film thickness tb of the free magnetic layer in both side regions B and B. Consequently, the magnetic flux density in the track-width region A of the free magnetic layer resulting from the static magnetic fields generated from both the side regions B and B of the free magnetic layer can be reduced, a dead zone which occurs in the track-width region A of the free magnetic layer can be reduced, and therefore, the magnetic field detection sensitivity is improved.
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: December 27, 2005
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu