Having Tunnel Junction Effect Patents (Class 360/324.2)
  • Patent number: 8217478
    Abstract: A magnetic stack having a ferromagnetic free layer, a metal oxide layer that is antiferromagnetic at a first temperature and non-magnetic at a second temperature higher than the first temperature, a ferromagnetic pinned reference layer, and a non-magnetic spacer layer between the free layer and the reference layer. During a writing process, the metal oxide layer is non-magnetic. For magnetic memory cells, such as magnetic tunnel junction cells, the metal oxide layer provides reduced switching currents.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: July 10, 2012
    Assignee: Seagate Technology LLC
    Inventors: Xiaohua Lou, Yuankai Zheng, Wenzhong Zhu, Wei Tian, Zheng Gao
  • Patent number: 8213132
    Abstract: A narrow track-width magnetoresistive sensor by defining a trench formed between first and second hard bias layers and depositing the sensor into the trench. The sensor can include a sensor stack sandwiched between first and second electrically conductive lead layers. First and second electrically insulating side walls are formed at either side of the sensor stack. First and second hard bias layers extend from the sides of the sensor stack, being separated from the sensor stack by the first and second electrically insulating side walls. First and second physically hard insulation layers are provided over each of the hard bias layers.
    Type: Grant
    Filed: November 12, 2007
    Date of Patent: July 3, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: David Eugene Heim, Kim Y. Lee, Tsann Lin, Jih-Shiuan Luo
  • Patent number: 8208228
    Abstract: A magnetoresistive (MR) sensor or read head for a magnetic recording disk drive has multiple independent current-perpendicular-to-the-plane (CPP) MR sensing elements. The sensing elements are spaced-apart in the cross-track direction and separated by an insulating separation region so as to be capable of reading data from multiple data tracks on the disk. The sensing elements have independent CPP sense currents, each of which is directed to independent data detection electronics, respectively. Each sensing element comprises a stack of layers formed on a common electrically conducting base layer, which may be a bottom magnetic shield layer formed of electrically conducting magnetically permeable material. Each sensing element has a top electrical lead layer. A top magnetic shield layer is located above the sensing elements in contact with the top lead layers.
    Type: Grant
    Filed: September 23, 2009
    Date of Patent: June 26, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Stefan Maat, James Terrence Olson, Hal J. Rosen
  • Patent number: 8208231
    Abstract: A tunneling magnetic sensing element includes a laminate in which a pinned magnetic layer having a magnetization direction pinned, an insulating barrier layer, and a free magnetic layer having a magnetization direction variable with an external magnetic field are laminated in order from below. The insulating barrier layer is made of Mg—O. The free magnetic layer has a soft magnetic layer and an enhanced layer disposed between the soft magnetic layer and the insulating barrier layer to have a spin polarization ratio higher than the soft magnetic layer. An insertion magnetic layer made of one selected from Co—Fe—B, Co—B, Fe—B, and Co—Fe is inserted into the soft magnetic layer in a direction parallel to the interface of each layer constituting the laminate, and the soft magnetic layer is divided into multiple layers in a thickness direction through the insertion magnetic layer.
    Type: Grant
    Filed: November 12, 2009
    Date of Patent: June 26, 2012
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kazumasa Nishimura, Hidekazu Kobayashi, Masamichi Saito, Yosuke Ide, Ryo Nakabayashi, Yoshihiro Nishiyama, Akio Hanada, Naoya Hasegawa
  • Patent number: 8202572
    Abstract: A method of forming a high performance magnetic tunnel junction (MTJ) is disclosed wherein the tunnel barrier includes at least three metal oxide layers. The tunnel barrier stack is partially built by depositing a first metal layer, performing a natural oxidation (NOX) process, depositing a second metal layer, and performing a second NOX process to give a MOX1/MOX2 configuration. An uppermost metal layer on the MOX2 layer is not oxidized until after the MTJ stack is completely formed and an annealing process is performed to drive unreacted oxygen in the MOX1 and MOX2 layers into the uppermost metal layer. In an alternative embodiment, a plurality of metal oxide layers is formed on the MOX1 layer before the uppermost metal layer is deposited. The resulting MTJ stack has an ultralow RA around 1 ohm-?m2 and maintains a high magnetoresistive ratio characteristic of a single metal oxide tunnel barrier layer.
    Type: Grant
    Filed: November 22, 2010
    Date of Patent: June 19, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui-Chuan Wang, Min Li, Kunliang Zhang
  • Patent number: 8198100
    Abstract: A detection device and a detecting method using the detection device are provided in which a magnetic particle is used as a marker particle, and the ratio of a region with reversed magnetization to the whole area of a free layer of a magnetoresistive effect film is increased by a stray magnetic field generated through a biochemical reaction from the magnetic particle remaining on a surface of the magnetoresistive effect film, so that a large detection signal is obtained and obtained detection data can be stored with stability.
    Type: Grant
    Filed: April 26, 2005
    Date of Patent: June 12, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Ikeda, Norihiko Utsunomiya, Junta Yamamichi
  • Patent number: 8194365
    Abstract: A method and system for providing a magnetic structure in magnetic transducer is described. The magnetic structure includes a pinned layer, a nonmagnetic spacer layer, and a free layer. The nonmagnetic spacer layer is between the pinned layer and the free layer. The free layer includes a first magnetic layer, a second magnetic layer, and a magnetic insertion layer between the first magnetic layer and the second magnetic layer. The first magnetic layer has a first magnetostriction. The second magnetic layer has a second magnetostriction opposite to the first magnetostriction. The magnetic insertion layer provides a growth texture barrier between the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: September 3, 2009
    Date of Patent: June 5, 2012
    Assignee: Western Digital (Fremont), LLC
    Inventors: Qunwen Leng, Chando Park, Yimin Guo, Christian Kaiser, Mahendra Pakala, Sining Mao
  • Patent number: 8194366
    Abstract: A tunneling magnetoresistance (TMR) read head and a method of producing the same are disclosed. A free layer having a free layer stripe height is provided, the free layer having a first side and a second side. A tunneling barrier layer is formed adjacent to the first side of the free layer, the tunneling barrier layer having a first side and a second side, the second side of the tunneling barrier layer facing the first side of the free layer. A pinned stack is formed adjacent to the first side of the tunneling barrier layer. The pinned stack comprises at least one magnetic layer having a current path stripe height that is less than the free layer stripe height.
    Type: Grant
    Filed: October 14, 2009
    Date of Patent: June 5, 2012
    Assignee: Western Digital (Fremont), LLC
    Inventors: Shaoping Li, Yimin Guo, Feng Liu, Wei Zhang, Sining Mao
  • Patent number: 8191235
    Abstract: The method of the present invention provides a magnetoresistance effect element, which is capable of having a high MR ratio, corresponding to high density recording and being suitably applied to a magnetoresistance device even though a barrier layer is thinned to reduce resistance of the magnetoresistance effect element. The method of producing the magnetoresistance effect element, which includes the barrier layer composed of an oxidized metal, a first magnetic layer contacting one of surfaces of the barrier layer and a second magnetic layer contacting the other surface thereof, comprises the steps of: laminating the barrier layer on the first magnetic layer with using a target composed of the oxidized metal; and laminating the second magnetic layer on the barrier layer. The barrier layer is annealed before laminating the second magnetic layer thereon.
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: June 5, 2012
    Assignees: Fujitsu Limited, Tohoku University
    Inventors: Migaku Takahashi, Masakiyo Tsunoda, Koujiro Komagaki, Yuji Uehara, Kazuyuki Sunaga
  • Patent number: 8189304
    Abstract: A magnetoresistive magnetic head according to one embodiment uses a current-perpendicular-to-plane magnetoresistive element having a laminate of a free layer, an intermediate layer, and a pinned layer, the pinned layer being substantially fixed to a magnetic field to be detected, wherein either the pinned layer or the free layer includes a Heusler alloy layer represented by a composition of X—Y—Z, wherein X is between about 45 at. % and about 55 at. % and is Co or Fe, Y accounts for between about 20 at. % and about 30 at. % and is one or more elements selected from V, Cr, Mn, and Fe, and Z is between about 20 at. % and about 35 at.
    Type: Grant
    Filed: December 11, 2009
    Date of Patent: May 29, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Susumu Okamura, Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya, Kenichi Meguro, Keizo Kato
  • Patent number: 8183654
    Abstract: Apparatus and associated method for writing data to a non-volatile memory cell, such as spin-torque transfer random access memory (STRAM). In accordance with some embodiments, a resistive sense element (RSE) has a heat assist region, magnetic tunneling junction (MTJ), and pinned region. When a first logical state is written to the MTJ with a spin polarized current, the pinned and heat assist regions each have a substantially zero net magnetic moment. When a second logical state is written to the MTJ with a static magnetic field, the pinned region has a substantially zero net magnetic moment and the heat assist region has a non-zero net magnetic moment.
    Type: Grant
    Filed: May 27, 2011
    Date of Patent: May 22, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Xiaohua Lou, Haiwen Xi, Michael Xuefei Tang
  • Patent number: 8183653
    Abstract: A magnetic tunnel junction includes an amorphous ferromagnetic reference layer having a first reference layer side and an opposing second reference layer side. The first reference layer side has a greater concentration of boron than the second reference layer side. A magnesium oxide tunnel barrier layer is disposed on the second side of the amorphous ferromagnetic reference layer. The magnesium oxide tunnel barrier layer has a crystal structure. An amorphous ferromagnetic free layer is disposed on the magnesium oxide tunnel barrier layer.
    Type: Grant
    Filed: July 13, 2009
    Date of Patent: May 22, 2012
    Assignee: Seagate Technology LLC
    Inventors: Xilin Peng, Konstantin Nikolaev, Taras Pokhil, Victor Sapazhnikov, Yonghua Chen
  • Patent number: 8184408
    Abstract: A magnetoresistive element includes a magnetoresistive film including a magnetization pinned layer, a magnetization free layer, an intermediate layer arranged between the magnetization pinned layer and the magnetization free layer, a cap layer arranged on the magnetization pinned layer or on the magnetization free layer, and a functional layer formed of an oxygen- or nitrogen-containing material and arranged in the magnetization pinned layer, or in the magnetization free layer, and a pair of electrodes which pass a current perpendicularly to a plane of the magnetoresistive film, in which a crystalline orientation plane of the functional layer is different from a crystalline orientation plane of its upper or lower adjacent layer.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: May 22, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shuichi Murakami, Hideaki Fukuzawa, Hiromi Yuasa, Yoshihiko Fuji
  • Patent number: 8184411
    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: Grant
    Filed: October 26, 2009
    Date of Patent: May 22, 2012
    Assignees: Headway Technologies, Inc., MagIC Technologies, Inc.
    Inventors: Kunliang Zhang, Min Li, Pokang Wang, Yuchen Zhou, Cheng T. Horng, Ru-Ying Tong
  • Patent number: 8176622
    Abstract: A process for manufacturing a high performance MTJ it is described: A first cap layer of NiFeHf is deposited on the free layer, followed by a second cap layer of Ru on Ta. The device is then heated so that oxygen trapped in the free layer diffuses into the NiFeHf layer, thereby sharpening the interface between the tunnel barrier layer and the free layer.
    Type: Grant
    Filed: January 27, 2010
    Date of Patent: May 15, 2012
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong, Chyu-Jiuh Torng, Witold Kula
  • Patent number: 8174800
    Abstract: A magnetoresistive element includes an antiferromagnetic layer formed from a layer containing manganese, a layered magnetization fixed layer which includes a first magnetization fixed layer located over a side of the antiferromagnetic layer and formed from a layer containing a ferromagnetic material and a platinum group metal, a second magnetization fixed layer formed from a layer containing a ferromagnetic material, and a first nonmagnetic intermediate layer located between the first magnetization fixed layer and the second magnetization fixed layer, a magnetic free layer formed from a layer containing a ferromagnetic material, and a second nonmagnetic intermediate layer located between the layered magnetization fixed layer and the magnetic free layer.
    Type: Grant
    Filed: May 2, 2008
    Date of Patent: May 8, 2012
    Assignee: Canon Anelva Corporation
    Inventors: Koji Tsunekawa, David Djayaprawira
  • Patent number: 8166630
    Abstract: To provide a manufacturing method which can adjust the lengths of a recording element and a reproducing element for enabling manufacture of high-quality magnetic head sliders. The manufacturing method comprises: a stacked-layer forming step which stacks magnetic heads on a substrate; a lapping step which cuts out a bar block having a plurality of connected magnetic head sliders, and polishes a flying surface; and a slider cutting step which cuts out individual magnetic head sliders from the bar block. The stacked-layer forming step forms a reproducing-element polish amount detecting sensor on a same layer as that of the reproducing element, and forms a recording-element polish amount detecting sensor on a same layer as that of the recording element. The lapping step carries out polishing based on each output value of the reproducing-element polish amount detecting sensor and the recording-element polish amount detecting sensor.
    Type: Grant
    Filed: November 3, 2008
    Date of Patent: May 1, 2012
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Ryuji Fujii, Ikuhito Onodera, Quan Bao Wang, Masahiro Kuribayashi
  • Patent number: 8169753
    Abstract: A current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with ferromagnetic amorphous buffer and polycrystalline seed layers is disclosed for reducing a read gap, in order to perform magnetic recording at higher linear densities. The ferromagnetic amorphous buffer and polycrystalline seed layers couples to a ferromagnetic lower shield, thus acting as part of the ferromagnetic lower shield and defining the upper surface of the ferromagnetic polycrystalline seed layer as the lower bound of the read gap. In addition, a CPP TMR or GMR read sensor with nonmagnetic and ferromagnetic cap layers is also disclosed for reducing the read gap, in order to perform magnetic recording at even higher linear densities. The ferromagnetic cap layer couples to a ferromagnetic upper shield, thus acting as part of the ferromagnetic upper shield and defining the lower surface of the ferromagnetic cap layer as the upper bound of the read gap.
    Type: Grant
    Filed: November 21, 2008
    Date of Patent: May 1, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Tsann Lin
  • Patent number: 8166633
    Abstract: A method for manufacturing an extraordinary magnetoresistive sensor (EMR sensor) having reduced size and increased resolution is described. The sensor includes a plurality of electrically conductive leads contacting a magnetically active layer and also includes an electrically conductive shunt structure. The electrically conductive leads of the sensor and the shunt structure can be formed in a common photolithographic masking and etching process so that they are self aligned with one another. This avoids the need to align multiple photolithographic processing steps, thereby allowing greatly increased resolution and reduced lead spacing. The EMR sensor can be formed with a magnetically active layer that can be close to or at the air bearing surface (ABS) for improved magnetic spacing with an adjacent magnetic medium of a data recording system.
    Type: Grant
    Filed: December 17, 2010
    Date of Patent: May 1, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Thomas Dudley Boone, Jr., Liesl Folks, Bruce Alvin Gurney, Jordan Asher Katine, Ernesto E. Marinero, Neil Smith
  • Patent number: 8169754
    Abstract: A disk drive head slider for a magnetic disk drive is provided. The head slider includes a tunnel magnetic resistance device for reading data on a magnetic disk and a dedicated noncorrosive smear detector for measuring resistance wherein the resistance corresponds to a level of smear associated with the head slider.
    Type: Grant
    Filed: December 31, 2007
    Date of Patent: May 1, 2012
    Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.
    Inventors: David P. Druist, David J. Seagle, Jila Tabib
  • Patent number: 8164862
    Abstract: A composite seed layer that reduces the shield to shield distance in a read head while improving Hex (exchange coupling field) and Hex/Hc (Hc=coercivity) is disclosed and has a SM/A/SM/B configuration in which the SM layers are soft magnetic layers, the A (amorphous) layer is made of at least one of Co, Fe, Ni, and includes one or more amorphous elements, and the B layer is a buffer layer that contacts the AFM (anti-ferromagnetic) layer in the spin valve. The SM/A/SM stack together with the S1 (bottom) shield forms an effective shield such that the buffer layer serves as the effective seed layer while maintaining a blocking temperature of 260° C. in the AFM layer. The lower SM layer may be omitted. Examples of the amorphous layer are CoFeB, CoFeZr, CoFeNb, CoFeHf, CoFeNiZr, CoFeNiHf, and CoFeNiNbZr while the buffer layer may be Cu, Ru, Cr, Al, or NiFeCr.
    Type: Grant
    Filed: April 2, 2008
    Date of Patent: April 24, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Tong Zhao, Hui-Chuan Wang, Min Li
  • Patent number: 8164863
    Abstract: The invention provides a current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with multiple ferromagnetic sense layers. In one embodiment of the invention, a CPP TMR read sensor comprises a first sense layer formed by a ferromagnetic polycrystalline Co—Fe film, a second sense layer formed by a ferromagnetic interstitial-type amorphous Co—Fe—B film, a third sense layer formed by a ferromagnetic substitute-type amorphous Co—Fe—X film where X is Hf, Zr or Y, and a fourth sense layer formed by a ferromagnetic Ni—Fe film. The third sense layer acts as a diffusion barrier layer to suppress Ni diffusion, thus allowing the incorporation of the Ni—Fe fourth sense layer for improving ferromagnetic properties of the multiple sense layers. The multiple sense layers induce spin-dependent scattering, thus facilitating the CPP TMR read sensor to exhibit a strong TMR effect.
    Type: Grant
    Filed: March 26, 2008
    Date of Patent: April 24, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Tsann Lin
  • Patent number: 8164864
    Abstract: A method and system for providing a magnetic transducer are disclosed. The method and system include providing a magnetic element that includes a free layer, a pinned layer, and a nonmagnetic spacer layer between the free layer and the pinned layer. The nonmagnetic spacer layer is a tunneling barrier layer. The free layer is configured to be biased in a first direction. The pinned layer has a pinned layer magnetization configured to be pinned in a second direction that is at a first angle from perpendicular to the ABS. The first angle is nonzero and different from ninety degrees. The second direction and the first direction form a second angle that is different from ninety degrees.
    Type: Grant
    Filed: July 16, 2009
    Date of Patent: April 24, 2012
    Assignee: Western Digital (Fremont), LLC
    Inventors: Christian Kaiser, Laurence L. Chen, Qunwen Leng
  • Patent number: 8154829
    Abstract: A tunneling magnetoresistance (TMR) device, like a TMR read head for a magnetic recording hard disk drive, has a magnesium oxide (MgO) tunneling barrier layer and a ferromagnetic underlayer beneath and in direct contact with the MgO tunneling barrier layer. The ferromagnetic underlayer comprises a crystalline material according to the formula (CoxFe(100-x))(100-y)Gey, where the subscripts represent atomic percent, x is between about 45 and 55, and y is between about 26 and 37. The ferromagnetic underlayer may be the CoxFe(100-x))(100-y)Gey portion of a bilayer of two ferromagnetic layers, for example a CoFe/(CoxFe(100-x))(100-y)Gey bilayer. The specific composition of the ferromagnetic underlayer improves the crystallinity of the MgO tunneling barrier after annealing and improves the tunneling magnetoresistance of the TMR device.
    Type: Grant
    Filed: September 3, 2009
    Date of Patent: April 10, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Matthew J. Carey, Jeffrey R. Childress, Stefan Maat
  • Patent number: 8151442
    Abstract: Magnetoresistive (MR) elements having flux guides defined by the free layer. The MR element includes a free layer, a spacer/barrier layer, a pinned layer, and a pinning layer. A back edge of the free layer (opposite the sensing surface of the MR element) extends past a back edge of the spacer/barrier layer. The portion of the free layer extending past the back edge of the spacer/barrier layer defines a continuous flux guide. The flux guide is processed to reduce the conductive characteristics of the flux guide, thereby reducing current shunt loss in the flux guide.
    Type: Grant
    Filed: March 31, 2010
    Date of Patent: April 10, 2012
    Assignee: Hitachi Global Strorage Technologies Netherlands, B.V.
    Inventor: Hardayal S. Gill
  • Patent number: 8146237
    Abstract: In a magnetic head manufacturing method, a floated surface of each block having plural magnetic head elements formed and arranged on a substrate is ground and lapped in a grinding/lapping step. The grinding/lapping step contains an angle adjusting step for adjusting the angle of the floated surface of the block with reference to a magnetic-head-element formed surface of a substrate and grinding the floated surface concerned, and a finishing lapping step of lapping the floated surface at an angle adjusted in the angle adjusting step.
    Type: Grant
    Filed: April 28, 2009
    Date of Patent: April 3, 2012
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Yoshiaki Ito, Osamu Fukuroi, Hiroyasu Tuchiya, Kenji Kodaka
  • Patent number: 8149549
    Abstract: A magnetoresistive head is provided with high reliability and produced at a high yield rate. The magnetoresistive head includes a lower magnetic shield layer, an upper magnetic shield layer, a magnetoresistive effect film, and means for causing a current to flow in the direction of the thickness of the magnetoresistive effect film. The magnetoresistive effect film is provided between the lower magnetic shield layer and the upper magnetic shield layer. The magnetoresistive effect film is composed of a fixed layer, a non-magnetic layer, an insulating barrier layer and a free layer. The four layers of the magnetoresistive effect film are formed in this order. The insulating barrier layer is an oxide layer containing at least one of titanium and nickel.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: April 3, 2012
    Assignee: Hitachi, Ltd.
    Inventor: Tomio Iwasaki
  • Patent number: 8139325
    Abstract: A tunnel magnetoresistive thin film has a high MR ratio and improves heat resistance while maintaining a thin film of a Ru layer used as a non-magnetic layer so that the Ru layer expresses a preferable exchange coupling magnetic field even through annealing is performed at a high temperature. In the tunnel magnetoresistive thin film, at least one of a first pinned magnetic layer and a second pinned magnetic layer that are layered having the non-magnetic layer for exchange coupling therebetween has a layered structure of two or more layers made of magnetic materials different from each other.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: March 20, 2012
    Assignee: Canon Anelva Corporation
    Inventors: Koji Tsunekawa, Yoshinori Nagamine
  • Patent number: 8136227
    Abstract: A magnetic head having non-GMR shunt for perpendicular recording and method for making magnetic head having non-GMR shunt for perpendicular recording is disclosed. A shunt is provided for shunting charge from a read sensor. The shunt is formed co-planar with the read sensor and is fabricated using non-GMR materials.
    Type: Grant
    Filed: October 11, 2005
    Date of Patent: March 20, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Michael Feldbaum, Quang Le, Edward H. Lee, Neil L. Robertson, Charles G. Seegel, III
  • Patent number: 8130476
    Abstract: A tunneling magnetic sensing element includes: a pinned magnetic layer whose direction of magnetization is pinned in one direction; an insulating barrier layer; and a free magnetic layer whose direction of magnetization changes in response to an external magnetic field. The pinned magnetic layer, the insulating barrier layer and the free magnetic layer are deposited in the named order. A first protective layer composed of a platinum-group element is disposed on the free magnetic layer, and a second protective layer composed of Ti is disposed on the first protective layer.
    Type: Grant
    Filed: May 9, 2008
    Date of Patent: March 6, 2012
    Assignee: TDK Corporation
    Inventors: Kazumasa Nishimura, Masamichi Saito, Yoshihiro Nishiyama, Hidekazu Kobayashi, Naoya Hasegawa
  • Patent number: 8130477
    Abstract: A magneto-resistance effect element, a magneto-resistance effect head, a magnetic storage and a magnetic memory, in which noise caused by a spin-transfer torque is reduced, are provided. In a fixed magnetization layer or a free magnetization layer of a magneto-resistance effect element including the fixed magnetization layer, a spacer layer and the free magnetization layer; a layer containing one element selected from the group consisting of Ti, Zr, Nb, Mo, Ru, Rh, Pd, Ag, La, Hf, Ta, W, Re, Os, Ir, Pt and Au is disposed.
    Type: Grant
    Filed: September 10, 2010
    Date of Patent: March 6, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hideaki Fukuzawa, Masahiro Takashita, Hiromi Yuasa, Yoshihiko Fuji, Hitoshi Iwasaki
  • Patent number: 8125746
    Abstract: A tunneling magneto-resistive reader includes a sensor stack separating a top magnetic shield from a bottom magnetic shield. The sensor stack includes a reference magnetic element having a reference magnetization orientation direction and a free magnetic element having a free magnetization orientation direction substantially perpendicular to the reference magnetization orientation direction. A non-magnetic spacer layer separates the reference magnetic element from the free magnetic element. A first side magnetic shield and a second side magnetic shield is disposed between the top magnetic shield from a bottom magnetic shield, and the sensor stack is between the first side magnetic shield and the second side magnetic shield. The first side magnetic shield and the second side magnetic shield electrically insulates the top magnetic shield from a bottom magnetic shield.
    Type: Grant
    Filed: July 13, 2009
    Date of Patent: February 28, 2012
    Assignee: Seagate Technology LLC
    Inventors: Dimitar V. Dimitrov, Zheng Gao, Wonjoon Jung, Paul Edward Anderson, Olle Gunnar Heinonen
  • Patent number: 8124253
    Abstract: A tunneling magnetic sensing element includes a laminate in which an underlayer, a seed layer, an antiferromagnetic layer, a pinned magnetic layer, an insulating barrier layer, and a free magnetic layer are laminated in order from below. The insulating barrier layer is made of Mg—O. The underlayer is made of Ti, and the seed layer is made of one selected from a group consisting of Ni—Fe—Cr and Ru.
    Type: Grant
    Filed: November 10, 2009
    Date of Patent: February 28, 2012
    Assignee: ALPS Electric Co., Ltd.
    Inventors: Kazumasa Nishimura, Masamichi Saito, Yosuke Ide, Ryo Nakabayashi, Yoshihiro Nishiyama, Hidekazu Kobayashi, Naoya Hasegawa
  • Patent number: 8125040
    Abstract: A method for forming a magnetic tunnel junction (MTJ) for magnetic random access memory (MRAM) using two masks includes depositing over an interlevel dielectric layer containing an exposed first interconnect metallization, a first electrode, a fixed magnetization layer, a tunneling barrier layer, a free magnetization layer and a second electrode. An MTJ structure including the tunnel barrier layer, free layer and second electrode is defined above the first interconnect metallization by a first mask. A first passivation layer encapsulates the MTJ structure, leaving the second electrode exposed. A third electrode is deposited in contact with the second electrode. A second mask is used to pattern a larger structure including the third electrode, the first passivation layer, the fixed magnetization layer and the first electrode. A second dielectric passivation layer covers the etched plurality of layers, the first interlevel dielectric layer and the first interconnect metallization.
    Type: Grant
    Filed: March 17, 2009
    Date of Patent: February 28, 2012
    Assignee: QUALCOMM Incorporated
    Inventors: Seung H. Kang, Xia Li, Shiqun Gu, Matthew Nowak
  • Patent number: 8120126
    Abstract: A magnetic tunneling junction device and fabrication method is disclosed. In a particular embodiment, the method includes depositing a capping material on a free layer of a magnetic tunneling junction structure to form the capping layer and oxidizing a portion of the capping material to form a layer of oxidized material.
    Type: Grant
    Filed: March 2, 2009
    Date of Patent: February 21, 2012
    Assignee: QUALCOMM Incorporated
    Inventors: Kangho Lee, Xiaochun Zhu, Xia Li, Seung H. Kang
  • Patent number: 8116043
    Abstract: A method and system for providing a magnetic structure in magnetic transducer is described. The method and system include providing a pinning layer, a synthetic antiferromagnetic (SAF) adjacent to the pinning layer, a nonmagnetic layer, and a sensor layer. The SAF resides between the nonmagnetic and pinning layers. The nonmagnetic layer is between the SAF and the sensor layer. The SAF includes a pinned layer, a reference layer, and a nonmagnetic spacer layer between the pinned and reference layers. The pinned layer is magnetically coupled with the reference layer and includes sublayers. A first sublayer has a first blocking temperature distribution (TBD) and a first exchange energy. A second sublayer has a second TBD and a second exchange energy. The first sublayer is between the pinning layer and second sublayer. The first TBD is greater than the second TBD. The first exchange energy is less than the second exchange energy.
    Type: Grant
    Filed: December 9, 2009
    Date of Patent: February 14, 2012
    Assignee: Western Digital (Fremont), LLC
    Inventors: Qunwen Leng, Jian X. Shen, Feng Liu, Geoffrey W. Anderson
  • Patent number: 8107202
    Abstract: A magnetoresistive sensor having an antiparallel coupled pinned layer structure including an AP1 layer and an AP2 layer. The AP2 layer includes two ferromagnetic layers AP2(a) and AP2(b), and a separation layer sandwiched therebetween. The AP2(a) layer is significantly larger than the AP2(b) layer, which results in strong pinning, while the separation layer provides increased TMR and reduced RA.
    Type: Grant
    Filed: December 30, 2008
    Date of Patent: January 31, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Wen-yaung Lee, Chang Man Park, Brian R. York, Alexander M. Zeltser
  • Patent number: 8102172
    Abstract: A circular top surface of a magnet is magnetized to the N-pole, and a back surface thereof is magnetized to the S-pole. A detector moves within the X-Y plane at positions located away from the top surface of the magnet. A pair of X-direction detecting elements and a pair of the Y-direction detecting elements are provided in the detector. In the X-direction detecting elements, the directions of a bias magnetic field provided to free magnetic layers are opposite to each other. When the detector moves in the Y direction, a decrease in the sensitivity of one of the X-direction detecting elements is compensated for by an improvement in the sensitivity of the other element. This also applies to the Y-direction detecting elements. Accordingly, position detection outputs of the X direction and the Y direction can be accurately obtained from the detector.
    Type: Grant
    Filed: October 23, 2008
    Date of Patent: January 24, 2012
    Assignee: Alps Electric Co., Ltd.
    Inventors: Tsutomu Takeya, Takafumi Noguchi
  • Patent number: 8098464
    Abstract: A magnetic field detecting element includes: first and second free layers; a spacer layer; a first exchange coupling transmitting layer; a first pinned layer; a second exchange coupling transmitting layer; and a second pinned layer. The first and second pinned layers are magnetized in directions which are perpendicular to an air bearing surface and which are anti-parallel with each other, respectively. The first exchange coupling transmitting layer or second exchange coupling transmitting layer has a positive exchange coupling strength, while the other has a negative exchange coupling strength. The first or second pinned layer that is located adjacent to the first or second exchange coupling transmitting layer having the negative exchange coupling strength has a larger magnetic film thickness than the first or second free layer that is located adjacent to the first or second exchange coupling transmitting layer having the negative exchange coupling strength.
    Type: Grant
    Filed: February 19, 2008
    Date of Patent: January 17, 2012
    Assignee: TDK Corporation
    Inventor: Koji Shimazawa
  • Patent number: 8094421
    Abstract: A current-to-perpendicular-to-plane (CPP) read sensor with multiple reference layers and associated fabrication methods are disclosed. According to one embodiment of the invention, the multiple reference layers of a CPP tunneling magnetoresistance (TMR) read sensor includes a first reference layer formed by a ferromagnetic polycrystalline Co—Fe film, a second reference layer formed by a ferromagnetic substitute-type amorphous Co—Fe—X film where X is Hf, Zr or Y, and a third reference layer formed by a ferromagnetic interstitial-type amorphous Co—Fe—B film. The first reference layer facilitates the CPP TMR read sensor to exhibit high exchange and antiparallel-coupling fields. The second reference layer provides a thermally stable flat surface, thus facilitating the CPP TMR read sensor to exhibit a low ferromagnetic-coupling field. The multiple reference layers may induce spin-dependent scattering, thus facilitating the CPP TMR sensor to exhibit a high TMR coefficient.
    Type: Grant
    Filed: December 26, 2007
    Date of Patent: January 10, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventor: Tsann Lin
  • Patent number: 8094420
    Abstract: The invention provides a magnetoresistive device of the CCP (current perpendicular to plane) structure comprising a magnetoresistive unit sandwiched between soft magnetic shield layers with a current applied in the stacking direction. The magnetoresistive unit comprises a nonmagnetic intermediate layer sandwiched between ferromagnetic layers. A planar framework positions the soft magnetic shield layers and comprises a combination of a nonmagnetic gap layer with a bias magnetic field-applying layer constructed by repeating the stacking of a multilayer unit comprising a nonmagnetic underlay layer and a high coercive material layer. The nonmagnetic gap layer is designed and located such that a magnetic flux given out of the bias magnetic field-applying layer is efficiently directed along a closed magnetic path around the framework to form a single domain of magnetization.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: January 10, 2012
    Assignee: TDK Corporation
    Inventors: Toshiyuki Ayukawa, Takahiko Machita, Daisuke Miyauchi, Tsutomu Chou, Koji Shimazawa, Shinji Hara, Tomohito Mizuno, Yoshihiro Tsuchiya
  • Patent number: 8089265
    Abstract: By subdividing the free layer of a GMR/TMR device into multiple sub-elements that share common top and bottom electrodes, a magnetic detector is produced that is domain stable in the presence of large stray fields, thereby eliminating the need for longitudinal bias magnets. Said detector may be used to measure electric currents without being affected by local temperature fluctuations and/or stray fields.
    Type: Grant
    Filed: January 26, 2009
    Date of Patent: January 3, 2012
    Assignee: MagIC Technologies, Inc.
    Inventors: Yimin Guo, Po-Kang Wang
  • Patent number: 8087157
    Abstract: Using a beam of xenon ions together with a suitable mask, a MTJ stack is ion milled until a part of it, no more than about 0.1 microns thick, has been removed so that a pedestal, having sidewalls comprising a vertical section that includes all of the free layer, has been formed. This is followed by formation of the longitudinal bias and conductive lead layers in the usual way. Using xenon as the sputtering gas enables the point at which milling is terminated to be more precisely controlled.
    Type: Grant
    Filed: October 18, 2007
    Date of Patent: January 3, 2012
    Assignees: Headway Technologies, Inc., TDK Corporation
    Inventors: Stuart Kao, Chunping Luo, Chaopeng Chen, Takahiko Machita, Daisuke Miyauchi, Jeiwei Chang
  • Patent number: 8085511
    Abstract: A magnetoresistance effect element includes a magnetoresistance effect film including a magnetically pinned layer having a magnetic material film whose direction of magnetization is pinned substantially in one direction, a magnetically free layer having a magnetic material film whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic metal intermediate layer located between said pinned layer and said free layer. The element also includes a pair of electrodes electrically connected to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film. At least one of the pinned layer and the free layer may include a thin-film insertion layer.
    Type: Grant
    Filed: September 23, 2008
    Date of Patent: December 27, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
  • Patent number: 8085513
    Abstract: An object is to provide a magnetic sensor permitting an increase in potential output. The magnetic sensor has a channel layer, a magnetization free layer provided on a first portion of the channel layer and configured to detect an external magnetic field, and a magnetization fixed layer provided on a second portion different from the first portion of the channel layer, and a cross-sectional area of the magnetization fixed layer in a surface opposed to the channel layer is larger than a cross-sectional area of the magnetization free layer in a surface opposed to the channel layer.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: December 27, 2011
    Assignee: TDK Corporation
    Inventor: Tomoyuki Sasaki
  • Patent number: 8081405
    Abstract: A current-to-perpendicular-to-plane (CPP) read sensor with multiple reference layers and associated fabrication methods are disclosed. According to one embodiment, the multiple reference layers of a CPP read sensor include a first reference layer (e.g., Co—Fe) formed by a ferromagnetic polycrystalline film, a second reference layer (e.g., Co—Fe—Hf) formed by a ferromagnetic amorphous film, a third reference layer (e.g., Co—Fe—B) formed by a ferromagnetic amorphous film, and a fourth reference layer (e.g., Co—Fe) formed by a ferromagnetic polycrystalline film. A plasma treatment is applied to the fourth reference layer for surface smoothening, and no replenishment is needed as long as the fourth reference layer is not completely removed after the plasma treatment. The fourth reference layer protects the surface of the third reference layer from spin polarization deterioration caused by the plasma treatment, thereby maintaining a strong TMR or GMR effect.
    Type: Grant
    Filed: May 29, 2008
    Date of Patent: December 20, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventor: Tsann Lin
  • Patent number: 8081403
    Abstract: A magnetic element includes a pinned layer, a nonferromagnetic spacer layer, and a free layer. The nonferromagnetic spacer layer resides between the pinned layer and the free layer. The free layer has a track width of not more than 0.08 micron.
    Type: Grant
    Filed: July 10, 2008
    Date of Patent: December 20, 2011
    Assignee: Western Digital (Fremont), LLC
    Inventors: Benjamin Chen, Hongping Yuan, Danning Yang, Wei Zhang, Hugh C. Hiner, Lei Wang, Yingjian Chen, Brant Nease
  • Patent number: 8081404
    Abstract: A magnetoresistive element includes: a free layer made of a ferromagnetic material, the free layer configured to change the direction of magnetization under the influence of an external magnetic field; an insulating layer overlaid on the free layer, the insulating layer made of an insulating material; an amorphous reference layer overlaid on the insulating layer, the amorphous reference layer made of a ferromagnetic material, the amorphous reference layer configured to fix the magnetization in a predetermined direction; a crystal layer overlaid on the amorphous reference layer, the crystal layer containing crystal grains; a non-magnetic layer overlaid on the crystal layer, the non-magnetic layer containing crystal grains having grown from the crystal grains in the crystal layer; and a pinned layer overlaid on the non-magnetic layer, the pinned layer configured to fix the magnetization in a predetermined direction.
    Type: Grant
    Filed: August 27, 2009
    Date of Patent: December 20, 2011
    Assignee: Fujitsu Limited
    Inventors: Takahiro Ibusuki, Shinjiro Umehara, Masashige Sato
  • Patent number: 8072714
    Abstract: A barrier layer is disposed over a pinned layer made of ferromagnetic material having a fixed magnetization direction, the barrier layer having a thickness allowing electrons to transmit therethrough by a tunneling phenomenon. A first free layer is disposed over the barrier layer, the first free layer being made of amorphous or fine crystalline soft magnetic material which changes a magnetization direction under an external magnetic field. A second free layer is disposed over the first free layer, the second free layer being made of crystalline soft magnetic material which changes a magnetization direction under an external magnetic field and being exchange-coupled to the first free layer. A tunneling magnetoresistance device is provided which has good magnetic characteristics and can suppress a tunnel resistance change rate from being lowered.
    Type: Grant
    Filed: March 11, 2011
    Date of Patent: December 6, 2011
    Assignee: Fujitsu Limited
    Inventors: Masashige Sato, Shinjiro Umehara, Takahiro Ibusuki
  • Patent number: 8072713
    Abstract: To provide a magnetic reading head that features high resolution and low noise, and that can support a hard disk with terabit-level surface recording density. A current is caused to flow from a pinned layer with its magnetization direction fixed by an antiferro magnetic material, to a non-magnetic thin wire having a portion affected by an external magnetic field and a portion not affected by the external magnetic field, so that spin polarized electrons are accumulated in the non-magnetic thin wire. A distance between voltage terminals of a voltmeter is set to less than the spin diffusion length of the non-magnetic thin wire. A change in the external magnetic field modulates some of the accumulated spin polarized electron, but does not others. Accordingly, an electrical potential difference depending on the external magnetic field is generated between the both end surfaces of the non-magnetic thin wire, and measured with the voltmeter.
    Type: Grant
    Filed: May 29, 2008
    Date of Patent: December 6, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Masaki Yamada, Hiromasa Takahashi