Magnetoresistive Patents (Class 428/811)
  • Patent number: 11133459
    Abstract: According to one embodiment, a magnetic element includes a first layer and a second layer. The first layer includes a first element and a second element. The first element includes at least one selected from the group consisting of Fe, Co, and Ni. The second element includes at least one selected from the group consisting of Ir and Os. The second layer is nonmagnetic.
    Type: Grant
    Filed: February 15, 2018
    Date of Patent: September 28, 2021
    Assignees: National Institute of Advanced Industrial Science and Technology, TOHOKU UNIVERSITY, NATIONAL INSTITUTE FOR MATERIALS SCIENCE
    Inventors: Takayuki Nozaki, Shinji Yuasa, Rachwal Anna Koziol, Masahito Tsujikawa, Masafumi Shirai, Kazuhiro Hono, Tadakatsu Ohkubo, Xiandong Xu
  • Patent number: 11072842
    Abstract: Provided is a rare earth thin film magnet having Nd, Fe and B as essential components, which is characterized in that a Nd—Fe—B base film is formed on a Si substrate having an oxide film formed on a surface thereof and has a composition in which the Nd content is higher than that of a stoichiometric composition and that a film (nano composite film) is formed on the base film and has a texture in which an ?-Fe phase and Nd2Fe14B are alternately arranged and three-dimensionally dispersed. The rare earth thin film magnet provided is less susceptible to the occurrence of film separation and substrate breakage and exhibits favorable magnetic properties.
    Type: Grant
    Filed: March 29, 2017
    Date of Patent: July 27, 2021
    Assignee: JX NIPPON MINING & METALS CORPORATION
    Inventors: Masaki Nakano, Hirotoshi Fukunaga, Takeshi Yanai, Hironobu Sawatari
  • Patent number: 11005029
    Abstract: A device is disclosed. The device includes a first magnetic layer and a tunnel barrier. The first magnetic layer has a volume uniaxial magnetic crystalline anisotropy. The magnetic moment of the first layer is substantially perpendicular to the first layer. The tunnel barrier is in proximity to the first magnetic layer. The orientation of the magnetic moment of the first magnetic layer is reversed by spin transfer torque induced by current passing between and through the first magnetic layer and the tunnel barrier.
    Type: Grant
    Filed: September 28, 2018
    Date of Patent: May 11, 2021
    Assignees: Samsung Electronics Co., Ltd.
    Inventors: Jaewoo Jeong, Mahesh G. Samant, Stuart S. P. Parkin, Yari Ferrante
  • Patent number: 10971360
    Abstract: A transistor comprises channel material having first and second opposing sides. A gate is on the first side of the channel material and a gate insulator is between the gate and the channel material. A first insulating material has first and second opposing sides, with the first side being adjacent the second side of the channel material. A second insulating material of different composition from that of the first insulating material is adjacent the second side of the first insulating material. The second insulating material has at least one of (a), (b), and (c), where, (a): lower oxygen diffusivity than the first material, (b): net positive charge, and (c): at least two times greater shear strength than the first material. In some embodiments, an array of elevationally-extending strings of memory cells comprises such transistors. Other embodiments, including method, are disclosed.
    Type: Grant
    Filed: September 25, 2019
    Date of Patent: April 6, 2021
    Assignee: Micron Technology, Inc.
    Inventors: David H. Wells, Anish A. Khandekar, Kunal Shrotri, Jie Li
  • Patent number: 10923150
    Abstract: The purpose of the present invention is to provide a magnetic recording medium having a stacked structure of a seed layer including (Mg1-xTix)O and a magnetic recording layer including an L10 ordered alloy, and having improved properties. The method for producing a magnetic recording layer according to the present invention includes the steps of: (1) preparing a substrate; (2) forming a seed layer including (Mg1-xTix)O onto the substrate; (3) plasma etching the seed layer in an atmosphere including inert gas; and (4) forming a magnetic recording layer including an ordered alloy onto the seed layer which has been subjected to the step (3).
    Type: Grant
    Filed: October 2, 2017
    Date of Patent: February 16, 2021
    Assignee: FUJI ELECTRIC CO., LTD.
    Inventors: Tomohiro Moriya, Hitoshi Nakata, Takehito Shimatsu
  • Patent number: 10317480
    Abstract: A magneto resistive device having a plurality of magneto resistive sensing elements. Each of the plurality of magneto resistive sensing elements has a free layer and a reference layer. The free layer has a rounded convex contour with an aspect ratio of 2 or greater. There may be one hundred or more magneto resistive sensing elements.
    Type: Grant
    Filed: October 13, 2015
    Date of Patent: June 11, 2019
    Assignee: Infineon Technologies AG
    Inventors: Wolfgang Raberg, Andreas Strasser
  • Patent number: 10249817
    Abstract: A magnetic device includes a free layer; a pinned layer; a tunnel barrier disposed between the free layer and the pinned layer; a polarization enhancement layer disposed between the tunnel barrier and the pinned layer; and a blocking layer disposed between the polarization enhancement layer and the pinned layer, wherein the blocking layer includes a first diffusion trap layer and a second diffusion trap layer disposed on the first diffusion trap layer.
    Type: Grant
    Filed: August 15, 2017
    Date of Patent: April 2, 2019
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Ki-woong Kim, Kee-won Kim, Se-chung Oh, Yong-sung Park, Ju-hyun Kim
  • Patent number: 9966529
    Abstract: A magnetic tunnel junction (MTJ) is disclosed wherein first and second interfaces of a free layer (FL) with a first metal oxide (Hk enhancing layer) and second metal oxide (tunnel barrier), respectively, produce perpendicular magnetic anisotropy (PMA) to increase thermal stability. In some embodiments, metal clusters are formed in the FL and are subsequently partially or fully oxidized by scavenging oxygen to generate additional FL/oxide interfaces that enhance PMA, provide an acceptable resistance x area (RA) value, and preserve the magnetoresistive ratio. In other embodiments, a continuous or discontinuous metal (M) or MQ alloy layer within the FL reacts with scavenged oxygen to form a partially oxidized metal or alloy layer that enhances PMA and maintains acceptable RA. M is one of Mg, Al, B, Ca, Ba, Sr, Ta, Si, Mn, Ti, Zr, or Hf, and Q is a transition metal, B, C, or Al.
    Type: Grant
    Filed: March 17, 2017
    Date of Patent: May 8, 2018
    Assignee: Headway Technologies, Inc.
    Inventors: Jodi Mari Iwata, Guenole Jan, Ru-Ying Tong, Po-Kang Wang
  • Patent number: 9865801
    Abstract: Integrated circuits and methods of producing the same are provided. In an exemplary embodiment, a method of producing an integrated circuit includes forming a fixed layer that includes a magnetic material overlying a substrate. A non-magnetic first tunnel barrier layer is formed overlying the fixed layer. A total free layer is formed overlying the first tunnel barrier layer, where the total free layer includes a first spacer layer between first and second free layers. The first free layer includes one or more of cobalt, iron, and boron. The first spacer layer is non-magnetic and includes a first spacer layer boron sink material that has a boride formation enthalpy lower than the boride formation enthalpy of cobalt.
    Type: Grant
    Filed: January 19, 2017
    Date of Patent: January 9, 2018
    Assignee: GLOBALFOUNDRIES SINGAPORE PTE. LTD.
    Inventors: Kazutaka Yamane, Vinayak Bharat Naik, Kangho Lee
  • Patent number: 9799822
    Abstract: A disclosed magnetic memory element includes: a magnetization free layer formed of a ferromagnetic substance having perpendicular magnetic anisotropy; a response layer provided so as to be opposed to the magnetization free layer and formed of a ferromagnetic substance having perpendicular magnetic anisotropy; a non-magnetic layer provided so as to be opposed to the response layer on a side opposite to the magnetization free layer and formed of a non-magnetic substance; and a reference layer provided so as to be opposed to the non-magnetic layer on a side opposite to the response layer and formed of a ferromagnetic substance having perpendicular magnetic anisotropy. The magnetization free layer includes a first magnetization fixed region and a second magnetization fixed region which have magnetization fixed in directions antiparallel to each other, and a magnetization free region in which a magnetization direction is variable.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: October 24, 2017
    Assignees: NEC CORPORATION, TOHOKU UNIVERSITY
    Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tadahiko Sugibayashi, Hideo Ohno, Shoji Ikeda, Michihiko Yamanouchi
  • Patent number: 9490422
    Abstract: Magnetoresistive random access memory (MRAM) devices and methods for making the same include growing a tunnel barrier layer on a first magnetic layer. A thin layer of non-wetting material is formed on the tunnel barrier layer, such that the non-wetting material forms distinct regions on the tunnel barrier layer. A second magnetic layer is grown on the tunnel barrier layer.
    Type: Grant
    Filed: July 30, 2015
    Date of Patent: November 8, 2016
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Guohan Hu, Daniel C. Worledge
  • Patent number: 9466785
    Abstract: Magnetoresistive random access memory (MRAM) devices and methods for making the same include growing a tunnel barrier layer on a first magnetic layer. A thin layer of non-wetting material is formed on the tunnel barrier layer, such that the non-wetting material forms distinct regions on the tunnel barrier layer. A second magnetic layer is grown on the tunnel barrier layer.
    Type: Grant
    Filed: July 30, 2015
    Date of Patent: October 11, 2016
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Guohan Hu, Daniel C. Worledge
  • Patent number: 9379317
    Abstract: Method of filtering electrons to obtain spin-polarization of a current conducting at least 75% of electrons at the Fermi level, used with a spin-polarized current source comprising: a polarized spin injection device comprising an electrically conducting substrate of which a first face has magnetic properties and an organic layer in contact with the first face of the substrate; an electrically conducting material called the ground, the organic layer being arranged between the ground and the substrate; a current source electrically connected to the first face of the substrate and the ground; the method comprising circulation of the electron conduction current by means of the current source, between the first face of the substrate and the ground, at a temperature higher than ?220° C.
    Type: Grant
    Filed: April 15, 2013
    Date of Patent: June 28, 2016
    Assignees: Centre National de la Recherche Scientifique, Universite de Strasbourg
    Inventors: Martin Bowen, Wolfgang Weber, Loïc Joly, Eric Beaurepaire, Fabrice Scheurer, Samy Boukari, Mébarek Alouani
  • Patent number: 9087977
    Abstract: A semiconductor device is provided having a free layer and a pinned layer spaced apart from each other. A tunnel barrier layer is formed between the free layer and the pinned layer. The pinned layer may include a lower pinned layer, and an upper pinned layer spaced apart from the lower pinned layer. A spacer may be formed between the lower pinned layer and the upper pinned layer. A non-magnetic junction layer may be disposed adjacent to the spacer or between layers in the upper or lower pinned layer.
    Type: Grant
    Filed: April 16, 2014
    Date of Patent: July 21, 2015
    Assignee: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Jeong-Heon Park, Ki-Woong Kim, Hee-Ju Shin, Joon-Myoung Lee, Woo-Jin Kim, Jae-Hoon Kim, Se-Chung Oh, Yun-Jae Lee
  • Patent number: 9028910
    Abstract: The present invention is directed to a method for manufacturing spin transfer torque magnetic random access memory (STTMRAM) devices. The method, which utilizes in-situ annealing and etch-back of the magnetic tunnel junction (MTJ) film stack, comprises the steps of depositing a barrier layer on top of a bottom magnetic layer and then depositing an interface magnetic layer on top of the barrier layer to form an MTJ film stack; annealing the MTJ film stack at a first temperature and then cool the MTJ film stack to a second temperature lower than the first temperature; etching away a top portion of the interface magnetic layer; and depositing at least one top layer on top of the etched interface magnetic layer. The method may further include the step of annealing the MTJ film stack at a third temperature between the first and second temperature after the step of depositing at least one top layer.
    Type: Grant
    Filed: May 8, 2014
    Date of Patent: May 12, 2015
    Assignee: Avalanche Technology, Inc.
    Inventors: Yuchen Zhou, Yiming Huai
  • Patent number: 9017832
    Abstract: Various embodiments may be generally directed to a magnetic element capable of optimized magnetoresistive data reading. Such a magnetic element may be configured at least with a magnetoresistive stack that has an electrode lamination having at least a transition metal layer disposed between a magnetically free layer of the magnetoresistive stack and an electrode layer of the electrode lamination.
    Type: Grant
    Filed: January 31, 2013
    Date of Patent: April 28, 2015
    Assignee: Seagate Technology LLC
    Inventors: Eric Walter Singleton, Liwen Tan, Jae-Young Yi
  • Patent number: 9017831
    Abstract: A thin-film magnetic oscillation element includes a pinned magnetic layer, a free magnetic layer, a nonmagnetic spacer layer provided between the pinned magnetic layer and the free magnetic layer, and a pair of electrodes, in which the easy axis of magnetization of the pinned magnetic layer lies in an in-plane direction of the plane of the pinned magnetic layer, and the easy axis of magnetization of the free magnetic layer lies in a direction normal to the plane of the free magnetic layer. Preferably, the relationship between the saturation magnetization Ms and the magnetic anisotropy field Ha of the free magnetic layer satisfies 1.257 Ms<Ha<12.57 Ms. More preferably, the free magnetic layer is composed of an alloy or a stacked film containing at least one element selected from Co, Ni, Fe, and B.
    Type: Grant
    Filed: February 27, 2013
    Date of Patent: April 28, 2015
    Assignee: TDK Corporation
    Inventors: Katsuyuki Nakada, Takahiro Suwa, Kuniyasu Ito, Yuji Kakinuma, Masato Takahashi
  • Publication number: 20140374860
    Abstract: Provided is a magnetic shield having improved shielding properties from an external magnetic field. A magnetic shield MS1 has in-plane magnetization as remanent magnetization, and is adapted to generate a perpendicular component in the magnetization direction by applying a magnetic field in the perpendicular direction to the magnetic shield.
    Type: Application
    Filed: June 5, 2014
    Publication date: December 25, 2014
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventor: Tetsuhiro SUZUKI
  • Patent number: 8917581
    Abstract: Articles of manufacture and methods of manufacturing such articles of manufacture are disclosed. The articles of manufacture may include a heat assisted magnetic recording (HAMR) transducer having a near field transducer (NFT) and a chimney thermally coupled to the NFT. The articles of manufacture may also include an electrical conductor having section with a reduced width that is thermally coupled to the chimney. The methods include applying an electrical current to the electrical conductor to generate heat in the section and annealing the chimney and the NFT from the heat generated.
    Type: Grant
    Filed: January 17, 2014
    Date of Patent: December 23, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventor: Michael L. Mallary
  • Patent number: 8911888
    Abstract: Magnetic memories and methods are disclosed. A magnetic memory as described herein includes a plurality of stacked data storage layers to form a three-dimensional magnetic memory. The data storage layers are each formed from a multi-layer structure. At ambient temperatures, the multi-layer structures exhibit an antiparallel coupling state with a near zero net magnetic moment. At higher transition temperatures, the multi-layer structures transition from the antiparallel coupling state to a parallel coupling state with a net magnetic moment. At yet higher temperatures, the multi-layer structure transitions from the antiparallel coupling state to a receiving state where the coercivity of the multi-layer structures drops below a particular level so that magnetic fields from write elements or neighboring data storage layers may imprint data into the data storage layer.
    Type: Grant
    Filed: December 16, 2007
    Date of Patent: December 16, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Olav Hellwig, Bruce D. Terris, Jan-Ulrich Thiele
  • Patent number: 8895161
    Abstract: A ferromagnetic graphene includes at least one antidot such that the ferromagnetic graphene has ferromagnetic characteristics. A spin valve device includes a ferromagnetic graphene. The ferromagnetic graphene includes a first region, a second region, and a third region. At least one antidot is formed in each of the first region and the third region. The first region and the third region are ferromagnetic regions, whereas the second region is a non-ferromagnetic region.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: November 25, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Sung-Hoon Lee
  • Patent number: 8871365
    Abstract: Enhanced Hc and Hk in addition to higher thermal stability to 400° C. are achieved in magnetic devices by adding dusting layers on top and bottom surfaces of a spacer in a synthetic antiferromagnetic (SAF) structure to give a RL1/DL1/spacer/DL2/RL2 reference layer configuration where RL1 and RL2 layers exhibit perpendicular magnetic anisotropy (PMA), the spacer induces antiferromagnetic coupling between RL1 and RL2, and DL1 and DL2 are dusting layers that enhance PMA. RL1 and RL2 layers are selected from laminates such as (Ni/Co)n, L10 alloys, or rare earth-transition metal alloys. The reference layer may be incorporated in STT-MRAM memory elements or in spintronic devices including a spin transfer oscillator. Dusting layers and a similar SAF design may be employed in a free layer for Ku enhancement and to increase the retention time of a memory cell.
    Type: Grant
    Filed: February 28, 2012
    Date of Patent: October 28, 2014
    Assignee: Headway Technologies, Inc.
    Inventors: Yu-Jen Wang, Witold Kula, Ru Ying Tong, Guenole Jan
  • Patent number: 8852676
    Abstract: A spin toque transfer magnetic random access memory (STTMRAM) element and a method of manufacturing the same is disclosed having a free sub-layer structure with enhanced internal stiffness. A first free sub-layer is deposited, the first free sub-layer being made partially of boron (B), annealing is performed of the STTMRAM element at a first temperature after depositing the first free sub-layer to reduce the B content at an interface between the first free sub-layer and the barrier layer, the annealing causing a second free sub-layer to be formed on top of the first free sub-layer and being made partially of B, the amount of B of the second free sub-layer being greater than the amount of B in the first free sub-layer.
    Type: Grant
    Filed: October 11, 2013
    Date of Patent: October 7, 2014
    Assignee: Avalanche Technology, Inc.
    Inventor: Yuchen Zhou
  • Patent number: 8829901
    Abstract: A method to measure a magnetic field is provided. The method includes applying an alternating drive current to a drive strap overlaying a magnetoresistive sensor to shift an operating point of the magnetoresistive sensor to a low noise region. An alternating magnetic drive field is generated in the magnetoresistive sensor by the alternating drive current. When the magnetic field to be measured is superimposed on the alternating magnetic drive field in the magnetoresistive sensor, the method further comprises extracting a second harmonic component of an output of the magnetoresistive sensor. The magnetic field to be measured is proportional to a signed amplitude of the extracted second harmonic component.
    Type: Grant
    Filed: November 4, 2011
    Date of Patent: September 9, 2014
    Assignee: Honeywell International Inc.
    Inventor: Bharat B. Pant
  • Patent number: 8755152
    Abstract: A method and system for providing a magnetic transducer is described. The method and system include providing a magnetic shield, an insertion layer on the magnetic shield, an antiferromagnetic (AFM) layer, a pinned layer magnetically coupled with the AFM layer, a nonmagnetic spacer layer, and a free layer. The magnetic shield has a texture and a grain size. The insertion layer has a thickness that is sufficiently large that the AFM layer is magnetically decoupled from the magnetic shield and sufficiently small that the AFM layer is structurally coupled with the magnetic shield. The pinned layer resides between the AFM layer and the nonmagnetic spacer layer. The nonmagnetic spacer layer resides between the free layer and the pinned layer.
    Type: Grant
    Filed: September 24, 2008
    Date of Patent: June 17, 2014
    Assignee: Western Digital (Fremont), LLC
    Inventors: Chando Park, Qunwen Leng, Min Zhou, Sangmun Oh, Mahendra Pakala
  • Patent number: 8709617
    Abstract: In accordance with one aspect of the invention, a magnetic memory element records information in a spin valve structure having a free layer, a pinning layer, and a nonmagnetic layer sandwiched therebetween. The magnetic memory element further has, on the free layer, a separate nonmagnetic layer and a magnetic change layer having magnetic characteristics which change according to temperature. Multiple cutouts, including one cutout with a different shape, are provided in a peripheral portion of the spin valve structure. A method of driving the magnetic memory element is characterized in that information is recorded by applying unipolar electric pulses.
    Type: Grant
    Filed: September 5, 2008
    Date of Patent: April 29, 2014
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Yasushi Ogimoto, Haruo Kawakami
  • Patent number: 8679653
    Abstract: A spin-valve element has a pair of ferromagnetic layers having mutually different coercive forces, sandwiching an insulating layer or a nonmagnetic layer therebetween. The in-plane shape of the spin-valve element is substantially circular in shape but is provided, in the peripheral portion, with a plurality of cutouts NS, NW, NE, NN. Preferably, the shape of at least one cutout be made different from that of others. Moreover, a storage device that employs such a spin-valve element is provided.
    Type: Grant
    Filed: September 5, 2008
    Date of Patent: March 25, 2014
    Assignee: Fuji Electric Co., Ltd.
    Inventors: Haruo Kawakami, Yasushi Ogimoto
  • Patent number: 8637170
    Abstract: A magnetic sensor comprises a support; a nonmagnetic conductive layer disposed on the support; a fixed magnetization layer disposed on a first part of the nonmagnetic conductive layer and on the support; a free magnetization layer disposed on a second part of the nonmagnetic conductive layer different from the first part and on the support; and a nonmagnetic low resistance layer, disposed on a part overlapping the nonmagnetic conductive layer in at least one of the fixed magnetization layer and free magnetization layer, having an electrical resistivity lower than that of the one layer.
    Type: Grant
    Filed: May 26, 2009
    Date of Patent: January 28, 2014
    Assignee: TDK Corporation
    Inventor: Tomoyuki Sasaki
  • Patent number: 8582249
    Abstract: A magnetic element has a magnetically responsive lamination with a ferromagnetic free layer separated from a synthetic antiferromagnetic (SAF) layer by a spacer layer and from a sensed data bit stored in an adjacent medium by an air bearing surface (ABS). The lamination is coupled to at least one antiferromagnetic (AFM) tab a predetermined offset distance from the ABS.
    Type: Grant
    Filed: April 26, 2011
    Date of Patent: November 12, 2013
    Assignee: Seagate Technology LLC
    Inventors: Victor Boris Sapozhnikov, Eric Walter Singleton, Mark William Covington
  • Patent number: 8558623
    Abstract: An oscillator including two groups of elementary junctions having giant magnetoresistance effect traversed by electric currents, the junctions of each of the two groups being in series and energized by respective main currents and the voltages across the terminals of the groups being added together to provide a voltage on an output of the oscillating circuit. The voltage across the terminals of one or more junctions of a first group is applied to a first input of a phase comparator and the voltage across the terminals of one or more junctions of the other group is applied to another input of the phase comparator, the phase comparator providing on two outputs secondary currents of the same amplitude and of opposite signs, which are dependent on the mean phase difference between the voltages applied to the inputs, the secondary currents each being added to a respective main current.
    Type: Grant
    Filed: December 15, 2011
    Date of Patent: October 15, 2013
    Assignee: Commissariat a l'Energie Atomique et aux Energies Alternatives
    Inventors: Mykhailo Zarudniev, Eric Colinet, Patrick Villard
  • Patent number: 8507113
    Abstract: The present invention is directed to align crystal c-axes in magnetic layers near two opposed junction wall surfaces of a magnetoresistive element so as to be almost perpendicular to the junction wall surfaces. A magnetic sensor stack body has, on sides of opposed junction wall surfaces of a magnetoresistive element, field regions for applying a bias magnetic field to the element. The field region has first and second magnetic layers having magnetic particles having crystal c-axes, the first magnetic layer is disposed adjacent to the junction wall surface in the field region, the crystal c-axes in the first magnetic layer are aligned and oriented along an ABS in a film plane, the second magnetic layer is disposed adjacent to the first magnetic layer in the field region, and the crystal c-axis directions in the second magnetic layer are distributed at random in a plane.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: August 13, 2013
    Assignee: Canon Anelva Corporation
    Inventors: Einstein Noel Abarra, Tetsuya Endo
  • Patent number: 8490279
    Abstract: A method of forming a hard bias (HB) structure for longitudinally biasing a free layer in a MR sensor is disclosed. A HB layer is formed with easy axis growth perpendicular to an underlying seed layer which is formed above a substrate and along two sidewalls of the sensor. In one embodiment, a conformal soft magnetic layer that may be a top shield is deposited on the HB layer to provide direct exchange coupling that compensates HB surface charges. Optionally, a thin capping layer on the HB layer enables magneto-static shield-HB coupling. After HB initialization, HB regions along the sensor sidewalls have magnetizations that are perpendicular to the sidewalls as a result of surface charges near the seed layer. Sidewalls may be extended into the substrate (bottom shield) to give enhanced protection against side reading.
    Type: Grant
    Filed: September 24, 2010
    Date of Patent: July 23, 2013
    Assignee: Headway Technologies, Inc.
    Inventors: Yuchen Zhou, Kenichi Takano, Kunliang Zhang
  • Publication number: 20130170068
    Abstract: A head for magnetic data recording that includes an embedded contact sensor. The embedded contact sensor detects head disk contact by detecting changes in temperature as a result of contact between the head and the disk. The embedded contact sensor includes a thermoresistive layer and a structure for pinning the magnetic domains of the thermoresistive layer. This pinning of the magnetic domains prevents the thermoresistive layer from changing resistance in response to magnetic fields (rather than temperature) so as to avoid unwanted signal noise as a result of a magnetic signal from the magnetic media.
    Type: Application
    Filed: December 28, 2011
    Publication date: July 4, 2013
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Shoji Natori
  • Patent number: 8435652
    Abstract: A magnetic stack structure is disclosed. The magnetic stack structure includes two metal layers and a free layer sandwiched by the two metal layers. The thickness of the free layer is 1-30 nm. The thickness of the metal layers are 0.1-20 nm respectively.
    Type: Grant
    Filed: July 9, 2009
    Date of Patent: May 7, 2013
    Assignee: National Yunlin University of Science and Technology
    Inventors: Te-Ho Wu, Lin-Hsiu Ye, Ching-Ming Lee
  • Patent number: 8404367
    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: October 19, 2011
    Date of Patent: March 26, 2013
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong
  • Patent number: 8361541
    Abstract: The subject matter disclosed herein provides methods for manufacturing an electronic lapping guide and a magnetic read head assembly. The magnetoresistive head assembly includes a sensing element that has a front edge and a front flux guide that has a back edge, such that the sensing element front edge and the front flux guide back edge share a common interface that defines an interface plane normal to the surface of a wafer substrate. The electronic lapping guide comprises a conductive material adapted to attach to two electrical leads for measuring a resistance through the conductive material. The conductive material may include a conductive material back edge aligned with the interface plane. The resistance of the conductive material may be inversely proportional to a conductive material length normal to the interface plane.
    Type: Grant
    Filed: July 28, 2009
    Date of Patent: January 29, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Edward Hin Pong Lee, David John Seagle
  • Patent number: 8295006
    Abstract: A magnetic sensor reduces thermal fluctuation and realizes high-sensitive signal detection using a spin Hall device of a simple structure configured with only one magnetic layer. The magnetic sensor includes a stacked film in which a nonmagnetic spin Hall layer, a nonmagnetic insulator layer, and a magnetic layer are stacked, an electrode nonmagnetic terminal pair connected to a side surface of the nonmagnetic spin Hall layer, and a unit applying a current in a film thickness direction of the stacked film. A thickness of the nonmagnetic spin Hall layer is thinner than twice a spin diffusion length of a material constituting the nonmagnetic spin Hall layer. A magnetization direction of the magnetic layer magnetized by an external magnetic field is detected due to the polarity of a voltage across both ends of the electrode nonmagnetic terminal pair.
    Type: Grant
    Filed: December 16, 2008
    Date of Patent: October 23, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Ryoko Sugano, Masahiko Ichimura, Hiromasa Takahashi
  • Patent number: 8274811
    Abstract: A spin transfer oscillator (STO) structure is disclosed that includes two assist layers with perpendicular magnetic anisotropy (PMA) to enable a field generation layer (FGL) to achieve an oscillation state at lower current density for MAMR applications. In one embodiment, the STO is formed between a main pole and write shield and the FGL has a synthetic anti-ferromagnetic structure. The STO configuration may be represented by seed layer/spin injection layer (SIL)/spacer/PMA layer 1/FGL/spacer/PMA layer 2/capping layer. The spacer may be Cu for giant magnetoresistive (GMR) devices or a metal oxide for tunneling magnetoresistive (TMR) devices. Alternatively, the FGL is a single ferromagnetic layer and the second PMA assist layer has a synthetic structure including two PMA layers with magnetic moment in opposite directions in a seed layer/SIL/spacer/PMA assist 1/FGL/spacer/PMA assist 2/capping layer configuration. SIL and PMA assist layers are laminates of (CoFe/Ni)x or the like.
    Type: Grant
    Filed: November 22, 2010
    Date of Patent: September 25, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Min Li, Yuchen Zhou
  • Patent number: 8242776
    Abstract: A semiconductor process and apparatus provide a high-performance magnetic field sensor from two differential sensor configurations (201, 211) which require only two distinct pinning axes (206, 216), where each differential sensor (e.g., 201) is formed from a Wheatstone bridge structure with four unshielded MTJ sensors (202-205), each of which includes a magnetic field pulse generator (e.g., 414) for selectively applying a field pulse to stabilize or restore the easy axis magnetization of the sense layers (e.g., 411) to eliminate micromagnetic domain switches during measurements of small magnetic fields.
    Type: Grant
    Filed: March 26, 2008
    Date of Patent: August 14, 2012
    Assignee: Everspin Technologies, Inc.
    Inventors: Phillip G. Mather, Young Sir Chung, Bradley N. Engel
  • Publication number: 20120182647
    Abstract: According to one embodiment, a magnetoresistive element includes a first ferromagnetic layer a magnetization direction of which is pinned, a second ferromagnetic layer a magnetization direction of which is changed depending on an external magnetic field, an intermediate layer arranged between the first ferromagnetic layer and the second ferromagnetic layer and including an insulating layer and a magnetic conductive column, an alloy layer formed between the magnetic conductive column in the intermediate layer and the second ferromagnetic layer and including at least one of FeCoAl and FeCoAlCu, and a pair of electrodes configured to supply a current perpendicularly to a film plane of a stacked film including the first ferromagnetic layer, the intermediate layer, the alloy layer and the second ferromagnetic layer.
    Type: Application
    Filed: January 30, 2012
    Publication date: July 19, 2012
    Inventors: Hiromi Fuke, Susumu Hashimoto, Masayuki Takagishi, Hitoshi Iwasaki
  • Patent number: 8158190
    Abstract: Techniques for attaining high performance magnetic memory devices are provided. In one aspect, a magnetic memory device comprising one or more free magnetic layers is provided. The one or more free magnetic layers comprise a low magnetization material adapted to have a saturation magnetization of less than or equal to about 600 electromagnetic units per cubic centimeter. The device may be configured such that a ratio of mean switching field associated with an array of non-interacting magnetic memory devices and a standard deviation of the switching field is greater than or equal to about 20. The magnetic memory device may comprise a magnetic random access memory (MRAM) device. A method of producing a magnetic memory device is also provided.
    Type: Grant
    Filed: May 30, 2008
    Date of Patent: April 17, 2012
    Assignee: International Business Machines Corporation
    Inventor: David W. Abraham
  • Patent number: 8105703
    Abstract: The conventional free layer in a CPP GMR or TMR read head has been replaced by a tri-layer laminate comprising Co rich CoFe, moderately Fe rich NiFe, and heavily Fe rich NiFe. The result is an improved device that has a higher MR ratio than prior art devices, while still maintaining free layer softness and acceptable magnetostriction. A process for manufacturing the device is described.
    Type: Grant
    Filed: June 19, 2008
    Date of Patent: January 31, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Hui-Chuan Wang, Min Li, Tong Zhao, Kunliang Zhang, Chyu-Jiuh Torng
  • 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: 8049567
    Abstract: A circuit comprising a DC current source and at least two spin torque oscillators, the at least two spin torque oscillators being electrically coupled to each other and to the DC current source. A circuit comprising phase shifting means is connected in such a way as to cause a phase shift between current and voltage through the spin torque oscillators. An advantage is that the controlled phase shift significantly increases the tolerance for deviating anisotropy fields, which makes manufacturing of spin torque oscillator devices much more feasible in practice.
    Type: Grant
    Filed: October 31, 2008
    Date of Patent: November 1, 2011
    Inventors: Johan Persson, Yan Zhou, Johan Åkerman
  • Patent number: 7951415
    Abstract: A pole layer has an end located in a medium facing surface, the end having: a first side close to a substrate; a second side located opposite to the first side; a third side connecting an end of the first side to an end of the second side; and a fourth side connecting the other end of the first side to the other end of the second side. The second side defines a track width. The end of the pole layer located in the medium facing surface has a width that decreases toward the first side. The pole layer is disposed in a groove of a pole-layer-encasing layer made of a nonmagnetic insulating material, with a nonmagnetic conductive film provided between the encasing layer and the pole layer. The pole layer incorporates: a first layer located closer to the surface of the groove; and a second layer located farther from the surface of the groove.
    Type: Grant
    Filed: August 15, 2008
    Date of Patent: May 31, 2011
    Assignee: Headway Technologies, Inc.
    Inventors: Yoshitaka Sasaki, Dong-Hong Li, Shigeki Tanemura, Hiroyuki Itoh
  • Patent number: 7948717
    Abstract: A magneto-resistance effect element includes a first magnetic layer of which a magnetization direction is fixed; a second magnetic layer of which a magnetization direction is fixed; an intermediate layer which is provided between the first magnetic layer and the second magnetic layer; and a pair of electrodes for flowing a current perpendicular to a film surface of the resultant laminated body comprised of the first magnetic layer, the second magnetic layer and the intermediate layer. The intermediate layer includes insulating portions and metallic portions containing at least one selected from the group consisting of Fe, Co, Ni, Cr and the metallic portions are contacted with the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: September 7, 2007
    Date of Patent: May 24, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Hideaki Fukuzawa, Yoshihiko Fuji
  • Publication number: 20110096443
    Abstract: A MTJ for a spintronic device is disclosed and includes a thin composite seed layer made of at least Ta and a metal layer having fcc(111) or hcp(001) texture as in Ta/Ti/Cu to enhance perpendicular magnetic anisotropy (PMA) in an overlying laminated layer with a (CoFe/Ni)X, (Co/NiFe)X, (Co/NiCo)X, (CoFe/NiFe)X, or (CoFe/NiCo)X composition where x is from 5 to 30. In one embodiment, a CPP-TMR spin valve has one or both of a laminated free layer and laminated reference layer with the aforementioned compositions. The MTJ includes an interfacial layer made of CoFeB, CoFeB/CoFe, or CoFe/CoFeB between each laminated structure and the tunnel barrier. The laminated layers are deposited by a low power and high Ar pressure process to avoid damaging interfaces between adjoining layers. Annealing occurs at 220° C. to 400° C. A laminated layer with high PMA may also be included in one or more layers of a spin transfer oscillator.
    Type: Application
    Filed: October 26, 2009
    Publication date: April 28, 2011
    Inventors: Kunliang Zhang, Min Li, Pokang Wang, Yuchen Zhou, Cheng T. Horng, Ru-Ying Tong
  • Patent number: 7906231
    Abstract: Magnetic tunneling devices are formed from a first body centered cubic (bcc) magnetic layer and a second bcc magnetic layer. At least one spacer layer of bcc material between these magnetic layers exchange couples the first and second bcc magnetic layers. A tunnel barrier in proximity with the second magnetic layer permits spin-polarized current to pass between the tunnel barrier and the second layer; the tunnel barrier may be either MgO and Mg—ZnO. The first magnetic layer, the spacer layer, the second magnetic layer, and the tunnel barrier are all preferably (100) oriented. The MgO and Mg—ZnO tunnel barriers are prepared by first depositing a metallic layer on the second magnetic layer (e.g., a Mg layer), thereby substantially reducing the oxygen content in this magnetic layer, which improves the performance of the tunnel barriers.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: March 15, 2011
    Assignee: International Business Machines Corporation
    Inventor: Stuart Stephen Papworth Parkin
  • Patent number: 7897200
    Abstract: The present invention provides a ferromagnetic/antiferromagnetic coupling film structure and a fabrication method thereof. The structure includes an antiferromagnetic layer of cobalt oxide having a thickness of 2 to 15 monolayers and formed on a substrate at a temperature ranging from 700K to 900K; and a ferromagnetic layer of cobalt having a thickness of at least one monolayer for being formed on the antiferromagnetic layer of cobalt oxide.
    Type: Grant
    Filed: July 31, 2008
    Date of Patent: March 1, 2011
    Assignee: National Chung Cheng University
    Inventors: Jyh-Shen Tsay, Chi-Wei Lee, Gung Chern
  • Patent number: 7870659
    Abstract: A method for defining a perpendicular magnetic head is provided. The method includes forming a portion of the read and write head including depositing a sensor film on a surface only over a region of the read head to form a sensor; depositing a full-film shaping pole layer over the write head; defining a track width of the sensor; patterning a photoresist to define a pole tip of the write head including write track width and flare position, and at the same time to define a back edge of the sensor; removing material of the sensor and pole tip from the areas not covered by the photoresist; completing the fabrication of the write and read head layers; and lapping the write pole concurrently with the sensor to define the flare position of the pole tip and to define a sensor height with accurate positioning of write head flare.
    Type: Grant
    Filed: September 7, 2007
    Date of Patent: January 18, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Vladimir Nikitin, Samuel Wei-san Yuan