Detail Of Free Layer Or Additional Film For Affecting Or Biasing The Free Layer Patents (Class 360/324.12)
  • Patent number: 7359162
    Abstract: There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, if a pinned layer and a free layer have a stacked construction of a magnetic layer and a non-magnetic layer or a stacked construction of a magnetic layer and a magnetic layer, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.
    Type: Grant
    Filed: October 22, 2004
    Date of Patent: April 15, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda
  • Patent number: 7355825
    Abstract: A magnetoresistive film is interposed between domain controlling films in a current-perpendicular-to-the-plane (CPP) structure magnetoresistive element. The domain controlling films are designed to establish a first biasing magnetic field of a first intensity across the magnetoresistive film along the front end of the magnetoresistive film and a second biasing magnetic field of a second intensity larger than the first intensity along the rear end of the magnetoresistive film. The second biasing magnetic field serves to establish a single domain property within the magnetoresistive film along the rear end. Although the first biasing magnetic field acts in the same direction as the current field at a position near the front end of the magnetoresistive film, the magnetization is allowed to reliably rotate near the front end. A sensing current having a larger current value can be supplied to the magnetoresistive film. The magnetoresistive film exhibits a sufficient sensitivity.
    Type: Grant
    Filed: March 4, 2005
    Date of Patent: April 8, 2008
    Assignee: Fujitsu Limited
    Inventor: Hirotaka Oshima
  • Patent number: 7351483
    Abstract: Magnetic tunnel junctions are constructed from a MgO or Mg—ZnO tunnel barrier and amorphous magnetic layers in proximity with, and on respective sides of, the tunnel barrier. The amorphous magnetic layer preferably includes Co and at least one additional element selected to make the layer amorphous, such as boron. Magnetic tunnel junctions formed from the amorphous magnetic layers and the tunnel barrier have tunneling magnetoresistance values of up to 200% or more.
    Type: Grant
    Filed: November 10, 2004
    Date of Patent: April 1, 2008
    Assignee: International Business Machines Corporation
    Inventor: Stuart Stephen Papwoth Parkin
  • Patent number: 7352542
    Abstract: A GMR sensor is disclosed for sensing magnetically recorded information on a data storage medium. The sensor includes a ferromagnetic free layer and a ferromagnetic pinned layer sandwiching an electrically conductive spacer layer. An engineered overlayer is formed on the free layer to decrease free layer magnetic thickness without reducing physical thickness.
    Type: Grant
    Filed: July 26, 2004
    Date of Patent: April 1, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V
    Inventors: Witold Kula, Alexander M. Zeltser
  • Patent number: 7352541
    Abstract: A current perpendicular to plane (CPP) giant magnetoresistive (GMR) sensor having an antiparallel coupled free layer including a first magnetic layer of Fe and a second magnetic layer of FeXN, where X can be Al or Ta. The first and second magnetic layers of the free layer are separated from one another by a Cr coupling layer. The sensor may also include an antiparallel coupling layer including Fe magnetic layers separated by a Cr coupling layer. The pinned and free layers may be separated by a Cr spacer layer.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: April 1, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Publication number: 20080074808
    Abstract: A magnetoresistive element 11 is formed with inclusion of a free layer 12, a pinned layer 13, an antiferromagnetic layer 14 for pinning the pinned layer 13, an intermediate layer 15 provided between the free layer 12 and the pinned layer 13, and a ferromagnetic layer 16 for applying a longitudinal bias magnetic field to the free layer. After initial magnetization, characteristic evaluation is conducted for the magnetoresistive element 11. Intensity of longitudinal bias field is adjusted by magnetizing again in a direction different from that of the initial magnetization, if required, on the basis of the evaluation result.
    Type: Application
    Filed: February 26, 2007
    Publication date: March 27, 2008
    Inventors: Hideyuki Akimoto, Naoki Mukoyama
  • 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: 20080062581
    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: Application
    Filed: July 2, 2004
    Publication date: March 13, 2008
    Inventor: Stuart Stephen Papworth Parkin
  • Patent number: 7341876
    Abstract: A method for fabricating a sensor having anti-parallel tab regions. The method includes forming a free layer having tab areas on opposite sides of an active area, forming a first layer of a carbon composition above the active area of the free layer, the first layer of carbon being substantially absent from tab areas of the free area, forming spacer layers above the tab areas of the free layer, the spacer layers being operable to make magnetic moments of ferromagnetic layers on opposite sides thereof antiparallel, forming bias layers above the spacer layers, the bias layers being operative to substantially pin magnetic moments of the tab areas of the free layer, forming second layers of carbon composition above the tab areas of the free layer, and removing the layers of carbon composition and any portions of the layers overlying the layers of carbon composition.
    Type: Grant
    Filed: August 30, 2005
    Date of Patent: March 11, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Marie-Claire Cyrille, Hardayal Singh Gill, James Mac Freitag
  • Patent number: 7342753
    Abstract: A magnetoresistive read element with improved biasing of the free layer is disclosed. The read element includes a free layer, a spacer layer, a first pinned bias layer, an APC layer, and a second pinned bias layer antiparallel exchange coupled with the first pinned bias layer. The second pinned bias layer has a width greater than the width of the first pinned bias layer, while the volumes of the first and second pinned bias layers are substantially similar. The width of the first pinned bias layer allows magnetic fields from the first pinned bias layer to longitudinally bias the free layer. The width of the second pinned bias layer avoids magnetic fields of the second pinned bias layer from biasing the free layer.
    Type: Grant
    Filed: January 20, 2005
    Date of Patent: March 11, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7342752
    Abstract: A magnetoresistive read head includes a magnetoresistive sensor and a bias structure adjacent to the magnetoresistive sensor. The bias structure provides a magnetostatic bias field for the magnetoresistive sensor. The bias structure includes an underlayer, a bias layer over the underlayer, and at least one dusting layer directly below at least one of the underlayer or the bias layer.
    Type: Grant
    Filed: January 31, 2004
    Date of Patent: March 11, 2008
    Assignee: Western Digital (Fremont), LLC
    Inventors: Wei Zhang, Yingjian Chen, Satoru Araki, Mohamad T Krounbi
  • Publication number: 20080055794
    Abstract: A magnetoresistive sensor having a pinned layer that extends beyond the free layer in the stripe height direction for improved shape enhanced pinning. The sensor includes hard bias layers and leads that extend in the stripe height direction beyond the stripe height of the free layer, providing increased conductive material for improved conduction of sense current to the sensor. The hard bias layers contact the sensor stack in the region between the ABS and the stripe height of the free layer, but are electrically insulated from the pinned layer in regions beyond the stripe height of the free layer by a layer of conformally deposited non-magnetic, electrically insulating material such as alumina.
    Type: Application
    Filed: August 30, 2006
    Publication date: March 6, 2008
    Inventors: James Mac Freitag, Mustafa Michael Pinarbasi
  • Publication number: 20080052896
    Abstract: A free layer functions such that a magnetization direction changes depending on an external magnetic field, and is made up of a multilayer structure including a first Heusler alloy layer, and a fixed magnetization layer takes a form wherein an inner pin layer and an outer pin layer are stacked one upon another with a nonmagnetic intermediated layer sandwiched between them. The inner pin layer is made up of a multilayer structure including a second Heusler alloy layer. The first and second Heusler alloy layers are each formed by a co-sputtering technique using a split target split into at least two sub-targets in such a way as to constitute a Heusler alloy layer composition. When the Heusler alloy layer is formed, therefore, it is possible to bring up a film-deposition rate, improve productivity, and improve the performance of the device.
    Type: Application
    Filed: June 1, 2007
    Publication date: March 6, 2008
    Applicant: TDK CORPORATION
    Inventors: Yoshihiro TSUCHIYA, Tomohito Mizuno, Koji Shimazawa
  • Patent number: 7336453
    Abstract: A magnetic sensing element using a thin film composed of an adequately crystallized Heusler alloy is provided. At least one of free magnetic layer and pinned magnetic layer includes a Heusler alloy layer. The Heusler alloy layer has a body-centered cubic (bcc) structure, in which equivalent crystal planes represented as [220] planes are preferentially oriented in the direction parallel to the layer surface. The Heusler alloy layer is disposed on a bcc layer having a body-centered cubic (bcc) structure, in which equivalent crystal planes represented as [110] planes are preferentially oriented in the direction parallel to the layer surface.
    Type: Grant
    Filed: September 29, 2004
    Date of Patent: February 26, 2008
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito, Yosuke Ide
  • Patent number: 7336454
    Abstract: A base film of a hard magnetic film containing Co as a structural element has a crystal metal base film such as a Cr film formed on the main surface of a substrate and a reactive base film (mixing layer) formed between the substrate and the crystal metal base film and having a reactive amorphous layer containing a structural element of the substrate and a structural element of the crystal metal base film. A hard magnetic film containing Co as a structural element is formed on the crystal metal base film. With the crystal metal base film such as the Cr film formed on an amorphous layer, a hard magnetic film with a bi-crystal structure can be obtained with high reproducibility. With the hard magnetic film, magnetic characteristics such as coercive force Hc, residual magnetization Mr, saturated magnetization Ms, and square ratio S can be improved without need to use a thick base film.
    Type: Grant
    Filed: May 4, 2006
    Date of Patent: February 26, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Shin-ichi Nakamura, Yuzo Kamiguchi, Hitoshi Iwasaki, Akio Hori, Susumu Hashimoto
  • Patent number: 7336451
    Abstract: A pinned magnetic layer 20 and a free magnetic layer 26 include a magnetic portion 17 and a magnetic sublayer 22, respectively, each comprising a half-metallic ferromagnetic alloy. Since each of the magnetic portion 17 and magnetic sublayer 22 comprising the half-metallic alloy layer has a larger value ? and a larger resistivity ? compared to the conventional CoFe alloy or the like, the change in resistance (?R) can be increased, and the rate of change in resistance (?R/R) can be appropriately improved.
    Type: Grant
    Filed: January 21, 2003
    Date of Patent: February 26, 2008
    Assignee: Alps Electric Co., Ltd.
    Inventor: Masamichi Saito
  • Patent number: 7333305
    Abstract: A magnetoresistive sensor having an in stack bias structure that extends beyond a stripe height edge defined by the free and pinned layers. The bias structure includes a magnetic bias layer that is magnetostatically coupled with the free layer by a non-magnetic spacer layer. The bias layer is pinned by an AFM layer that is disposed outside of the active area of the sensor beyond the stripe height edge. The AFM layer is exchange coupled with the bias layer on the same side of the bias layer that contacts the spacer layer. This reduces the gap height by moving the AFM layer up within the level of the other sensor layers.
    Type: Grant
    Filed: July 22, 2005
    Date of Patent: February 19, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7333304
    Abstract: A current perpendicular to plane (CPP) having hard magnetic bias layers located at the back of the sensor, opposite the air bearing surface. The bias layer is magnetostatically coupled with the free layer to bias the free layer in a desired direction parallel with the ABS. First and second magnetic shield layers may be provided at either lateral side of the sensor to provide exceptional track width definition. The placement of the bias layer at the back of the sensor makes possible the addition of magnetic shields at the sides of the sensor.
    Type: Grant
    Filed: November 4, 2004
    Date of Patent: February 19, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Kuok San Ho
  • 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: 7330340
    Abstract: A magnetoresistive sensor having a free layer biased by an in stack bias layer that has a magnetic moment canted with respect to the ABS, such that the magnetic moment of the biasing layer has a longitudinal component in a direction parallel with the ABS and a component in a transverse direction that is perpendicular to the ABS. The transverse component of the bias layer moment creates a balancing field in the free layer that counterbalances the coupling field in the free layer generated by the pinned layer. The counterbalance field provided by the canted moment of the biasing layer is especially useful in a tunnel valve sensor, because the very thin barrier layer of the tunnel valve design generates a strong coupling field in the free layer and this coupling field cannot be offset by a field from the sensor current.
    Type: Grant
    Filed: February 7, 2005
    Date of Patent: February 12, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Publication number: 20080030907
    Abstract: A tunneling magnetic sensing element is provided, in which an increase in the magnetostriction of a free magnetic layer is reduced and the rate of change in resistance is high. A laminate T1 constituting the tunneling magnetic sensing element includes a portion in which a pinned magnetic layer, a barrier layer, and a free magnetic layer are disposed in that order from the bottom. An enhancing layer disposed on the barrier layer side of the free magnetic layer includes a first enhancing layer on the barrier layer side and a second enhancing layer on the soft magnetic layer side, and the Fe content of a CoFe alloy constituting the first enhancing layer is specified to be larger than the Fe content of the CoFe alloy of the second enhancing layer.
    Type: Application
    Filed: July 24, 2007
    Publication date: February 7, 2008
    Inventors: Ryo Nakabayashi, Naoya Hasegawn, Masamichi Saito, Masahiko Ishizone, Yosuke Ide, Takuya Seino, Kazumasa Nishimura
  • 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: 7324313
    Abstract: Current-perpendicular-to-the-plane (CPP), current-in-to-the-plane (CIP), and tunnel valve type sensors are provided having an antiparallel (AP) coupled free layer structure, an in-stack biasing structure which stabilizes the AP coupled free layer structure and a nonmagnetic spacer layer formed between the in-stack biasing layer and the AP coupled free layer structure. The AP coupled free layer structure has a first AP coupled free layer adjacent to the nonmagnetic spacer layer, a second AP coupled free layer, and an antiparallel coupling (APC) layer formed between the first and the second AP coupled free layers. The net moment of the AP coupled free layer structure has an antiparallel edge magnetostatic coupling with the in-stack biasing structure. At the same time, the first AP coupled free layer has an antiparallel exchange coupling with the second AP coupled free layer.
    Type: Grant
    Filed: September 30, 2004
    Date of Patent: January 29, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Jeffrey Robinson Childress, Robert E. Fontana, Jr., Kuok San Ho, Ching Hwa Tsang
  • Patent number: 7324311
    Abstract: A magnetoresistive sensor having a trackwidth defined by AFM biasing layers disposed beneath a free layer of the sensor. The present invention provides a current in plane magnetoresistive sensor that includes a non-magnetic, electrically conductive layer in a trackwidth region. The non-magnetic, electrically conductive layer can be for example Ta, but could be some other material. This non-magnetic, electrically conductive layer has first and second laterally opposed sides and a planar upper surface. First and second insulating layers are formed at each of the sides of the non-magnetic, electrically conductive layer, and bias layers extend laterally outward from the insulation layers. The bias layers can be constructed of either an antiferromagnetic (AFM) material or could be constructed of a hard magnetic material such as CoPtCr. The bias layers have planar upper surfaces that are coplanar with the upper surface of the non-magnetic, electrically conductive layer.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: January 29, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kim Y. Lee, Tsann Lin
  • Patent number: 7324312
    Abstract: A magnetic head having an in-stack bias structure and a free layer structure. The in-stack bias structure includes an antiferromagnetic layer; a first bias layer positioned towards the antiferromagnetic layer, a magnetic moment of the first bias layer being pinned by the antiferromagnetic layer; a first antiparallel coupling layer positioned adjacent the first bias layer; and a second bias layer positioned between the first and second antiparallel coupling layers and having a magnetic moment pinned antiparallel to the magnetic moment of the first bias layer. A second antiparallel coupling layer is positioned adjacent the second bias layer of the bias structure. The free layer structure, positioned adjacent the antiparallel coupling layer, includes a first free layer having a magnetic moment and a second free layer having a magnetic moment pinned antiparallel to the magnetic moment of the first free layer.
    Type: Grant
    Filed: August 30, 2004
    Date of Patent: January 29, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7324309
    Abstract: A magnetoresistive read/write head includes an integral top and side shields deposited on top of and substantially surrounding the multiple layers of the MR sensor stack. Such a design is particularly advantageous in CPP designs in which the only spacing necessary between the side shields and the bottom shield is due to a gap layer. The integral top and side shields design works both with CPP heads having pile bias stabilization as well as those having permanent magnet abutted junctions or patterned exchange bias stabilization. In addition, the design is also advantageous in CIP heads having permanent magnet abutted junctions or patterned exchange bias stabilization. In this latter embodiment, it may be possible to reduce the profile of the permanent magnet and any conductors to increase the efficacy of the side shields.
    Type: Grant
    Filed: September 24, 2003
    Date of Patent: January 29, 2008
    Assignee: Maxtor Corporation
    Inventors: Kurt Wiesen, William R. Cross
  • Publication number: 20080019060
    Abstract: The invention provides a magneto-resistive effect device having a CPP (current perpendicular to plane) structure comprising a nonmagnetic spacer layer, and a fixed magnetized layer and a free layer stacked one upon another with said nonmagnetic spacer layer sandwiched between them, with a sense current applied in a stacking direction, wherein said free layer functions such that its magnetization direction changes depending on an external magnetic field, and is made up of a multilayer structure including a Heusler alloy layer, wherein an Fe layer is formed on one of both planes of said Heusler alloy layer in the stacking direction, wherein said one plane is near to at least a nonmagnetic spacer layer side, and said fixed magnetization layer is made up of a multilayer structure including a Heusler alloy layer, wherein Fe layers are formed on both plane sides of said Heusler alloy layer in the stacking direction with said Heusler alloy layer sandwiched between them.
    Type: Application
    Filed: June 13, 2007
    Publication date: January 24, 2008
    Applicant: TDK CORPORATION
    Inventors: Tomohito MIZUNO, Yoshihiro Tsuchiya, Koji Shimazawa
  • Publication number: 20080007877
    Abstract: A CPP type magneto-resistance effect element includes a magneto-resistance effect film with a fixed magnetization layer, a free magnetization layer and a non-magnetic intermediate layer; and a perpendicular biasing mechanism configured to apply a perpendicular biasing magnetic field to the free magnetization layer under the condition that the biasing magnetic field is parallel to a main surface of the magneto-resistance effect film and perpendicular to the magnetization of the fixed magnetization layer. Then, the magneto-resistance effect element satisfies the relation of 1.2?MRH/MRT when the width parallel to the perpendicular biasing magnetic field is defined as MRT and the width orthogonal to the perpendicular biasing magnetic field and parallel to a signal magnetic field.
    Type: Application
    Filed: February 23, 2007
    Publication date: January 10, 2008
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masahiro Takashita, Masayuki Takagishi, Hitoshi Iwasaki
  • Patent number: 7313857
    Abstract: A method of manufacturing a magneto-resistive device is provided for reducing a degradation in device characteristics due to annealing. The method includes the steps of depositing constituent layers, which make up a magneto-resistive layer on a base, patterning one or more layers of the constituent layers, forming an insulating layer in a region in which the one or more layers of the constituent layers have been removed by the patterning. For forming the insulating layer, the insulating layer is deposited while irradiating an ion beam of a gas mainly containing a rare gas toward the base after the step of patterning.
    Type: Grant
    Filed: June 8, 2004
    Date of Patent: January 1, 2008
    Assignee: TDK Corporation
    Inventors: Takayasu Kanaya, Takeo Kagami
  • Publication number: 20070297104
    Abstract: A method for manufacturing a magnetic field detecting element having a free layer whose magnetization direction is variable depending on an external magnetic field and a pinned layer whose magnetization direction is fixed with respect to the external magnetic field, said free layer and said pinned layer being stacked with an electrically conductive, nonmagnetic spacer layer sandwiched therebetween, wherein sense current is configured to flow in a direction that is perpendicular to film planes of the magnetic field detecting element is provided. The method has the steps of: forming a spacer adjoining layer that is adjacent to said spacer layer, Heusler alloy layer, and a metal layer successively in this order; and forming either at least a part of said pinned layer or said free layer by heating said spacer adjoining layer, said Heusler alloy layer, and said metal layer. The spacer adjoining layer has a layer that is chiefly made of cobalt and iron.
    Type: Application
    Filed: June 22, 2007
    Publication date: December 27, 2007
    Inventors: Tomohito MIZUNO, Yoshihiro TSUCHIYA, Koji SHIMAZAWA, Kei HIRATA, Keita KAWAMORI
  • Publication number: 20070297103
    Abstract: A spin valve structure is disclosed in which an AP1 layer and/or free layer are made of a laminated Heusler alloy having Al or FeCo insertion layers. The ordering temperature of a Heusler alloy such as Co2MnSi is thereby lowered from about 350° C. to 280° C. which becomes practical for spintronics device applications. The insertion layer is 0.5 to 5 Angstroms thick and may also be Sn, Ge, Ga, Sb, or Cr. The AP1 layer or free layer can contain one or two additional FeCo layers to give a configuration represented by FeCo/[HA/IL]nHA, [HA/IL]nHA/FeCo, or FeCo/[HA/IL]nHA/FeCo where n is an integer?1, HA is a Heusler alloy layer, and IL is an insertion layer. Optionally, a Heusler alloy insertion scheme is possible by doping Al or FeCo in the HA layer. For example, Co2MnSi may be co-sputtered with an Al or FeCo target or with a Co2MnAl or Co2FeSi target.
    Type: Application
    Filed: June 21, 2006
    Publication date: December 27, 2007
    Inventors: Kunliang Zhang, Min Li, Yu-Hsia Chen, Hui-Chuan Wang, Tong Zhao
  • Patent number: 7312961
    Abstract: A magnetic head has less variations in the resistance of a magneto-resistive device before and after the magnetic head is left in a high temperature environment so as to have higher stability of the characteristics of the magnetic head against a high temperature environment. A TMR device includes a tunnel barrier layer made of an oxide layer. A DLC film serving as a protection film and an underlying layer therefor are formed on an end face of the TMR device on an air bearing surface side. A layer made of an oxide of a metal or an oxide of a semiconductor is formed between the underlying layer and the end face of the tunnel barrier layer on the air bearing surface side to be in contact with the end face of the tunnel barrier layer.
    Type: Grant
    Filed: September 21, 2004
    Date of Patent: December 25, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Kentaro Nagai
  • Patent number: 7312959
    Abstract: At two sides of a multilayer film including a free magnetic layer, a first non-magnetic material layer, and a fixed magnetic layer, extension portions extending from the fixed magnetic layer are formed. At lower sides of the extension portions, a pair of first antiferromagnetic layers is formed with a space therebetween in a track width direction, and in addition, at upper sides of the extension portions, a pair of second antiferromagnetic layers is formed with a space therebetween in the track width direction.
    Type: Grant
    Filed: September 21, 2004
    Date of Patent: December 25, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Ryou Nakabayashi, Eiji Umetsu, Naoya Hasegawa
  • Patent number: 7310210
    Abstract: A magnetoresistive sensor comprises a pinned layer having a magnetization direction fixed with respect to an external magnetic field, a free layer, having a magnetization direction variable in accordance with the external magnetic field, and a spacer layer mainly containing copper, sandwiched between the pinned layer and the free layer. A sense current flows through the pinned layer, the spacer layer, and the free layer substantially in a direction in which the layers are stacked.
    Type: Grant
    Filed: January 27, 2005
    Date of Patent: December 18, 2007
    Assignee: TDK Corporation
    Inventors: Daisuke Miyauchi, Tomohito Mizuno
  • Patent number: 7310209
    Abstract: A magnetoresistive sensor having hard bias layers constructed of CoPtCrB, which high coercivity when deposited over crystalline materials such as an AFM layer or other sensor material. The bias layer material exhibits high coercivity and high moment even when deposited over a crystalline structure such as that of an underlying sensor material by not assuming the crystalline structure of the underlying crystalline layer. The bias layer material is especially beneficial for use in a partial mill sensor design wherein a portion of the sensor layers extends beyond the active area of the sensor and the bias layer must be deposited on the extended portion of sensor material.
    Type: Grant
    Filed: September 29, 2004
    Date of Patent: December 18, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Mustafa Michael Pinarbasi
  • Patent number: 7310207
    Abstract: A magnetic sensing element using a Heusler alloy is provided. In the magnetic sensing element, a free magnetic layer composed of a Heusler alloy layer is disposed on a nonmagnetic layer that corresponds to an fcc layer having the face-centered cubic (fcc) structure. Equivalent crystal planes represented as [111] planes in the fcc structure, which are the closest packed planes, are exposed on the surface of the nonmagnetic layer.
    Type: Grant
    Filed: September 29, 2004
    Date of Patent: December 18, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito, Yosuke Ide
  • Publication number: 20070285849
    Abstract: A magnetic read head of either CIP or CPP configuration is disclosed having a read sensor having oxidized non-conductive regions. The read sensor has a front edge, a rear edge, a left-side edge and a right-side edge. For a CIP configuration, the front edge and the rear edge are oxidized to form non-conductive regions. For a CPP configuration, the left-side edge, the right-side edge, the front edge and the rear edge are oxidized to form non-conductive regions. Also disclosed are a disk drive including a read sensor having oxidized non-conductive regions, and a method of fabrication for a read sensor having oxidized non-conductive regions.
    Type: Application
    Filed: June 9, 2006
    Publication date: December 13, 2007
    Inventor: Wipul Pemsiri Jayasekara
  • Patent number: 7307818
    Abstract: A method and system for providing a spin filter is disclosed. The method and system include providing a pinned layer, a free layer, and a conductive nonmagnetic spacer layer between the pinned layer and the free layer. The method and system also include providing a spin filter layer and a capping layer on the spin filter layer. The spin filter layer is adjacent to the free layer. The spin filter layer is on an opposite side of the free layer as the nonmagnetic spacer layer and includes at least Pt and/or Rh. The capping layer has a specular reflection layer therein. In one aspect, the specular reflection layer allows specular reflection of current carriers traveling from the spin filter layer to the specular reflection layer. In another aspect, the specular reflection layer includes at least Ta, Ti, Zr, Hf, Nb, Al, Mo, W, Si, Cr, V, Ni, Co, and Fe.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: December 11, 2007
    Assignee: Western Digital (Fremont), LLC
    Inventors: Chang-Man Park, Shin Funada, Amritpal S. Rana, Lena Miloslavsky
  • Publication number: 20070274010
    Abstract: An MR element incorporates a nonmagnetic conductive layer, and a pinned layer and a free layer that are disposed to sandwich the nonmagnetic conductive layer. Each of the pinned layer and the free layer includes a Heusler alloy layer. The Heusler alloy layer contains a Heusler alloy in which atoms of a magnetic metallic element are placed at body-centered positions of unit cells, and an additive element that is a nonmagnetic metallic element that does not constitute the Heusler alloy. At least one of the pinned layer and the free layer includes a region in which the concentration of the additive element increases as the distance from the nonmagnetic conductive layer decreases, the region being adjacent to the nonmagnetic conductive layer.
    Type: Application
    Filed: March 20, 2007
    Publication date: November 29, 2007
    Applicant: TDK CORPORATION
    Inventors: Kei Hirata, Yoshihiro Tsuchiya, Tomohito Mizuno, Koji Shimazawa
  • Patent number: 7301735
    Abstract: A magnetoresistive sensor having an in stack bias layer extending beyond the track width of the sensor for improved free layer stability and resistance against amplitude flipping.
    Type: Grant
    Filed: March 15, 2004
    Date of Patent: November 27, 2007
    Assignee: Hitachi Global Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • 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: 7301734
    Abstract: A GMR sensor having improved longitudinal biasing is provided as is a method of forming it. The improved biasing is provided by longitudinal biasing structures in which a soft magnetic layer is interposed between a hard magnetic biasing layer and the lateral edge of the GMR sensor element. The soft magnetic layer eliminates the need for a seed layer directly between the hard magnetic layer and the GMR element and provides improved coupling to the free layer of the GMR element and a substantial reduction in random domain variations.
    Type: Grant
    Filed: August 24, 2005
    Date of Patent: November 27, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Yimin Guo, Li-Yan Zhu
  • Patent number: 7298596
    Abstract: A magneto-resistance effect head is provided with a lower conductive layer which is provided with a recessed portion, and a vertical bias layer is provided in the recessed portion. A free layer is provided on the lower conductive layer. On the free layer, layered in the following order are the non-magnetic layer, the fixed layer, the fixing layer, and the upper layer so as not to be placed immediately above the vertical bias layer. The non-magnetic layer, the fixed layer, the fixing layer, and the upper layer are buried in an insulation layer. Furthermore, an upper conductive layer is provided on the upper layer and the insulation layer. In the direction of the magnetic field applied by the vertical bias layer, the free layer is made greater in length than the fixed layer and the free layer is disposed in proximity to the vertical bias layer with the distance between the fixed layer and the vertical bias layer remaining unchanged.
    Type: Grant
    Filed: June 30, 2006
    Date of Patent: November 20, 2007
    Assignee: NEC Corporation
    Inventors: Kazuhiko Hayashi, Junichi Fujikata, Tsutomu Ishi, Shigeru Mori, Keishi Ohashi, Masafumi Nakada, Kiyokazu Nagahara, Kunihiko Ishihara, Nobuyuki Ishiwata
  • Patent number: 7298595
    Abstract: A method for providing a self-pinned differential GMR sensor and self-pinned differential GMR sensor. The differential GMR head includes two self-pinned GMR sensors separated by a gap layer. The gap layer may act as a bias structure to provide antiparallel magnetizations for the first and second free layers without using an antiferromagnetic layer. The gap layer may include four NiFe ferromagnetic layers separated with three interlayers. The gap may also be formed to include a structure defined by Ta/Al2O3/NiFeCr/CuOx. One of the pinned layer may include three ferromagnetic layers so that the top ferromagnetic layer of the bottom pinned layer and the bottom ferromagnetic layer of the bottom pinned layer have a magnetization 180° out of phase. The self-pinned GMR sensors may include synthetic free layers that includes a first free sublayer, an interlayer and a second free sublayer that are biased 180° out of phase.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: November 20, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7295409
    Abstract: A CPP giant magnetoresistive element includes a multilayer film including a lower pinned magnetic layer having a laminated ferrimagnetic structure including a lower first pinned magnetic sublayer, a lower nonmagnetic intermediate sublayer, and a lower second pinned magnetic sublayer; a lower nonmagnetic layer; a free magnetic layer; an upper nonmagnetic layer; and an upper pinned magnetic layer having a laminated ferrimagnetic structure including an upper second pinned magnetic sublayer, an upper nonmagnetic intermediate sublayer, and an upper first pinned magnetic sublayer disposed in that order. Each of the free magnetic layer and the lower and upper second pinned magnetic sublayers is composed of a NiFeX alloy or NiFeCoX alloy, X being an element which decreases the saturation magnetization of a NiFe or NiFeCo base.
    Type: Grant
    Filed: May 10, 2004
    Date of Patent: November 13, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7292416
    Abstract: A magnetoresistive head comprises a free magnetic layer that has first and second free magnetic films sandwiching a non-magnetic intermediate film therebetween, the respective magnetizing directions of the first and the second free magnetic films are antiparallel. The length of the free magnetic layer in the direction of the track width is 200 nm or less, and a difference between a product of saturation magnetic flux density and a film thickness of the first free magnetic film, and that of the second free magnetic film is within a range from 1 to 3 nmT. By this structure, the variation of output and the variation of asymmetry is greatly decreased at a track width of 200 nm or less.
    Type: Grant
    Filed: March 8, 2006
    Date of Patent: November 6, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Takayoshi Ohtsu, Satoshi Shigematsu, Kouji Nishioka, Takao Imagawa, Kouji Kataoka, Masatoshi Arasawa, Norifumi Miyamoto
  • Patent number: 7292415
    Abstract: A magnetoresistive film includes a pinned ferromagnetic layer, a free ferromagnetic layer, an intermediate layer interposed between the pinned and free ferromagnetic layers, and a pinning layer contacting the pinned ferromagnetic layer. The free ferromagnetic layer is made of a ferromagnetic layered material including a cobalt nickel iron alloy layer, and a cobalt iron alloy layer laid over the cobalt nickel iron alloy layer. It has been demonstrated that the cobalt nickel iron alloy layer serves to reliably establish the uniaxial magnetic anisotropy in the cobalt iron alloy layer. Moreover, even if the thickness of the cobalt nickel iron alloy layer as well as the cobalt iron alloy layer is reduced, the uniaxial magnetic anisotropy can surely be maintained in the ferromagnetic layered material.
    Type: Grant
    Filed: December 23, 2002
    Date of Patent: November 6, 2007
    Assignee: Fujitsu Limited
    Inventor: Kenji Noma
  • Patent number: 7289305
    Abstract: A magnetoresistive element has a magnetization pinned layer, a nonmagnetic spacer layer including a stack of a nonmagnetic metal layer, a resistance increasing layer and another nonmagnetic metal layer, a magnetization free layer having an fcc crystal structure, a cap layer having an fcc, an hcp, or a bcc crystal structure and having an interatomic distance between nearest neighbors greater than that of the magnetization free layer, and a pair of electrodes configured to provide a sense current in a direction substantially perpendicular to planes of the magnetization pinned layer, the nonmagnetic spacer layer, and the magnetization free layer.
    Type: Grant
    Filed: March 9, 2005
    Date of Patent: October 30, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Fuke, Hideaki Fukuzawa, Hiromi Yuasa, Susumu Hashimoto, Hitoshi Iwasaki