Detail Of Pinned Film Or Additional Film For Affecting Or Biasing The Pinned Film Patents (Class 360/324.11)
  • Patent number: 7248445
    Abstract: A magnetic sensing element includes a composite film, a lower shield layer, and a lower electrode layer and an upper electrode layer for supplying a current perpendicular to the composite film. The composite film has an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic layer, and a free magnetic layer. The composite film has a top face and two side faces in a track width direction. Each of the two side faces has a bent position. The angle defined by the side face below the bent position and the top face is larger than the angle defined by the side face above the bent position and the top face. The bent portion preferably lies on the lower electrode layer or the lower shield layer.
    Type: Grant
    Filed: September 11, 2002
    Date of Patent: July 24, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventor: Yoshihiro Nishiyama
  • Patent number: 7245462
    Abstract: A method and system for providing a magnetic element is disclosed. The method and system include providing a ferromagnetic pinned layer, providing a free layer, and providing a spacer layer between the pinned layer and the free layer. The pinned layer and free layer are ferromagnetic and have a pinned layer magnetization and a free layer magnetization, respectively. The spacer layer is nonmagnetic. In one aspect, the free layer is configured to have an increased magnetic damping constant. In another aspect, the method and system also include providing a second pinned layer and a second spacer layer between the free layer and the second pinned layer. In this aspect, the first pinned layer and/or the second pinned layer are configured such that a forward torque and a reflected torque due to a current driven through the magnetic element in a current-perpendicular-to-plane configuration are substantially equal and opposite.
    Type: Grant
    Filed: May 5, 2004
    Date of Patent: July 17, 2007
    Assignee: Grandis, Inc.
    Inventors: Yiming Huai, Paul P. Nguyen
  • Patent number: 7237321
    Abstract: A method is described which uses a CMP resistant metal layer to replace the upper dielectric layer in the track width definition phase of a TMR or CPP spin valve magnetic head. The metal which is selected to be resistant to the CMP process can be rhodium (Rh), platinum (Pt), chromium (Cr), vanadium (V), etc. The additional CMP resistance of the refill layer structure provides a much larger processing window which results in higher yields. A CPP head according to the invention has a metal layer according to the invention above the hard bias structures on the sides of the sensor which define the track width.
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: July 3, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Marie-Claire Cyrille, Frederick Hayes Dill, Jui-Lung Li
  • Patent number: 7237322
    Abstract: A method for making a tunnel valve head with a flux guide. The tunnel valve sensor is created by forming a tunnel valve at a first shield layer. The tunnel valve includes a free layer distal to the first shield layer, a first insulation layer deposited over the first shield layer and around the tunnel valve, a flux guide formed over the first insulation layer and coupling to the tunnel valve at the free layer, a second insulation layer formed over the flux guide and a second shield layer formed over the second insulation layer. The flux guide and the free layer are physically isolated by the first and second insulation layers to prevent current shunts therefrom. The structure achieves physical connection between the flux guide and the free layer and insulates the flux guide from the shields.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: July 3, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7234228
    Abstract: A method for forming a bottom spin valve sensor element with a novel seed layer and synthetic antiferromagnetic pinned layer. The novel seed layer comprises an approximately 30 angstrom thick layer of NiCr whose atomic percent of Cr is 31%. On this seed layer there can be formed either a single bottom spin valve read sensor or a symmetric dual spin valve read sensor having synthetic antiferromagnetic pinned layers. An extremely thin (approximately 80 angstroms) MnPt pinning layer can be formed directly on the seed layer and extremely thin pinned and free layers can then subsequently be formed so that the sensors can be used to read recorded media with densities exceeding 60 Gb/in2. Moreover, the high pinning field and optimum magnetostriction produces an extremely robust sensor.
    Type: Grant
    Filed: December 3, 2002
    Date of Patent: June 26, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Cheng T. Horng, Hui-Chuan Wang, Ru-Ying Tong, Chyu-Jiuh Trong
  • Patent number: 7229706
    Abstract: The present invention provides a magnetic detecting element capable of increasing a difference between the ease of a conduction electron flow in a low-resistance state and the ease of a conduction electron flow in a high-resistance state to increase a resistance change ?R. In the magnetic detecting element, a free magnetic layer or a pinned magnetic layer has a synthetic ferromagnetic structure including a first free magnetic sub-layer or a first pinned magnetic sub-layer containing a magnetic material having a positive ? value, and a second magnetic sub-layer or a second pinned magnetic sub-layer containing a magnetic material having a negative ? value. The ? value is characteristics of a magnetic material satisfying the relationship ??/??=(1+?)/(1??)(?1???1)(wherein ?? represents resistivity for minority conduction electrons, and ?? represents resistivity for majority conduction electrons).
    Type: Grant
    Filed: January 12, 2004
    Date of Patent: June 12, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7228617
    Abstract: The GMR read head includes a GMR read sensor and a longitudinal bias (LB) stack in a read region, and the GMR read sensor, the LB stack and a first conductor layer in two overlay regions. In its fabrication process, the GMR read sensor, the LB stack and the first conductor layer are sequentially deposited on a bottom gap layer. A monolayer photoresist is deposited, exposed and developed in order to open a read trench region for the definition of a read width, and RIE is then applied to remove the first conductor layer in the read trench region. After liftoff of the monolayer photoresist, bilayer photoresists are deposited, exposed and developed in order to mask the read and overlay regions, and a second conductor layer is deposited in two unmasked side regions. As a result, side reading is eliminated and a read width is sharply defined by RIE.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: June 12, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Tsann Lin, Daniele Mauri
  • Patent number: 7223485
    Abstract: A magnetoresistive device includes a magnetization pinned layer, a magnetization free layer, a nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer, and electrodes allowing a sense current to flow in a direction substantially perpendicular to the plane of the stack including the magnetization pinned layer, the nonmagnetic intermediate layer and the magnetization free layer. At least one of the magnetization pinned layer and the magnetization free layer is substantially formed of a binary or ternary alloy represented by the formula FeaCobNic (where a+b+c=100 at %, and a?75 at %, b?75 at %, and c?63 at %), or formed of an alloy having a body-centered cubic crystal structure.
    Type: Grant
    Filed: March 7, 2005
    Date of Patent: May 29, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiromi Yuasa, Masatoshi Yoshikawa, Yuzo Kamiguchi, Hitoshi Iwasaki, Masashi Sahashi
  • Patent number: 7224556
    Abstract: A charge-perpendicular-to-plane self-pinned magnetic tunnel junction sensor is provided. Additionally, a disk drive using a charge-perpendicular-to-plane self-pinned magnetic tunnel junction sensor as the read element is provided.
    Type: Grant
    Filed: October 24, 2002
    Date of Patent: May 29, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Mustafa Pinarbasi
  • Patent number: 7220499
    Abstract: A CPP giant magnetoresistive head includes lower and upper shield layers with a predetermined distance therebetween, and a giant magnetoresistive element (GMR) including pinned and free magnetic layers disposed between the upper and lower shield layers with a nonmagnetic layer interposed between the pinned and free magnetic layers. A current flows perpendicularly to the film plane of the GMR. The magnetoresistive head further includes an antiferromagnetic layer (an insulating AF of Ni—O or ?-Fe2O3) provided in the rear of the GMR in a height direction to make contact with the upper or lower surface of a rear portion of the pinned magnetic layer which extends in the height direction, and an exchange coupling magnetic field is produced at the interface with the upper or lower surface, so that the magnetization direction of the pinned magnetic layer is pinned by the exchange coupling magnetic field in the height direction.
    Type: Grant
    Filed: April 13, 2004
    Date of Patent: May 22, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Yoshihiro Nishiyama, Yosuke Ide, Eiji Umetsu, Naoya Hasegawa, Yasuo Hayakawa
  • Patent number: 7221546
    Abstract: A longitudinal bias magnetic field control layer applies a counter bias magnetic field to a soft magnetic layer that is antiparallel (in opposite direction) to a longitudinal bias magnetic field. A magnitude of the counter bias magnetic field applied to the soft magnetic layer by the longitudinal bias magnetic field control layer is set smaller than that of the longitudinal bias magnetic field at a track center portion of the soft magnetic layer applied by a pair of bias magnetic field applying layers. A substantial longitudinal bias magnetic field is substantially applied to the soft magnetic layer in the same direction as that of the longitudinal bias magnetic field, and a magnitude of the substantial longitudinal bias magnetic field is maximum at both end portions of the soft magnetic layer and is weakened at the center portion of the soft magnetic layer.
    Type: Grant
    Filed: April 28, 2004
    Date of Patent: May 22, 2007
    Assignee: TDK Corporation
    Inventors: Koichi Terunuma, Koji Shimazawa, Yoshihiro Tsuchiya
  • Patent number: 7221545
    Abstract: A magnetic head having a free layer, an antiparallel (AP) pinned layer structure spaced apart from the free layer, and a high coercivity structure. The high coercivity structure pins a magnetic orientation of the AP pinned layer structure. The high coercivity structure includes a layer of high coercivity material, and an amorphous layer positioned between the high coercivity material and the AP pinned layer structure.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: May 22, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7218486
    Abstract: A magnetoresistive sensor having a self pinned structure formed above a free layer and having a pinning stabilization structure to avoid flipping of the magnetic moment of the pinned layer. The pinned layer stabilization structure includes hard magnetic structures formed over the leads in an area outside of the active area of the sensor, and a magnetic layer extends over the active area of the sensor and over the hard magnetic structures outside of the active area of the sensor.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: May 15, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7218487
    Abstract: An exchange coupling film including an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer so as to generate an exchange coupling magnetic field is provided. A PtMn alloy is used as the material of the antiferromagnetic layer. Crystal planes of the antiferromagnetic layer and the ferromagnetic layer preferentially aligned parallel to the interface are crystallographically identical and crystallographically identical axes lying in these crystal planes are oriented, at least partly, in different directions between the antiferromagnetic layer and the ferromagnetic layer. Thus, a proper order transformation occurs in the antiferromagnetic layer as a result of heat treatment and an increased exchange coupling magnetic field can be obtained.
    Type: Grant
    Filed: April 24, 2006
    Date of Patent: May 15, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7218485
    Abstract: A free magnetic layer contains free magnetic material layers and an intermediate layer interposed therebetween. A fixed magnetic layer contains fixed magnetic material layers and a non-magnetic intermediate layer interposed therebetween. The free magnetic material layer and the fixed magnetic material layers are formed at equivalent film positions. The magnetizations of the fixed magnetic material layers provided in a vertical direction are antiparallel to each other, and the magnetizations of the free magnetic material layers provided in the vertical direction are antiparallel to each other. By an external magnetic field, the magnetizations of the free magnetic material layer are rotated in phase to magnetization directions of the fixed magnetic material layers.
    Type: Grant
    Filed: January 12, 2004
    Date of Patent: May 15, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7215516
    Abstract: A magnetoresistive head includes a first magnetic shield, a first insulating film, a magnetoresistive film, a second insulating film and a second magnetic shield arranged in a track direction. The magnetoresistive film includes a magnetization free layer adjacent to an air-bearing surface, a magnetization pinned layer spaced apart from the magnetization free layer in a head height direction as viewed from the air-bearing surface, and a nonmagnetic intermediate layer connecting the magnetization free layer and the magnetization pinned layer, a magnetization direction of the magnetization free layer being rotatable in an external magnetic field and a magnetization direction of the magnetization pinned layer being substantially pinned under the external magnetic field.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: May 8, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi
  • Patent number: 7209326
    Abstract: A magnetoresistive head in which a pinned layer comprises two films, i.e., a ferromagnetic film A and a ferromagnetic B anti-ferromagnetically coupled to each other and a anti-ferromagnetic coupling film for separating the two ferromagnetic films A and B, where the coercivity of the ferromagnetic film alone is 200 (Oe) or more and the coercivity of the ferromagnetic film alone is 20 (Oe) or less. The compositions for the ferromagnetic film A and the ferromagnetic film B, when expressed by Co100-YFeY (at %) are: ferromagnetic film A: 80?Y?40, and ferromagnetic film B: 20?Y?0, where the material for the film in contact with the ferromagnetic film A is Ru, Ta, NiFeCr, Cu or NiFe.
    Type: Grant
    Filed: March 18, 2004
    Date of Patent: April 24, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Koichi Nishioka, Satoshi Shigematsu
  • Patent number: 7206174
    Abstract: A magnetoresistance effect element is manufactured in the steps in which a first ferromagnetic layer is formed on a substrate, the first ferromagnetic layer is patterned to form a pinned layer, in the shape of a strip, having both end portions to which electrode pads are formed, the pinned layer is etched, for example, through ion milling, so as to form at least one nano-contact portion, an insulating layer is formed by embedding an insulating material into the etched pinned layer around the nano-contact portion, a second ferromagnetic layer is formed so as to contact at least the nano-contact portion, and this second ferromagnetic layer is patterned to form a free layer, in shape of strip, having both end portions to which electrode pads are formed.
    Type: Grant
    Filed: July 2, 2004
    Date of Patent: April 17, 2007
    Assignee: TDK Corporation
    Inventors: Rachid Sbiaa, Isamu Sato
  • Patent number: 7203039
    Abstract: As track density requirements for disk drives have grown more aggressive, GMR devices have been pushed to narrower track widths to match the track pitch of the drive width. Narrower track widths degrade stability, cause amplitude loss, due to the field originating from the hard bias structure, and side reading. This problem has been overcome by adding an additional layer of soft magnetic material above the hard bias layers. The added layer provides flux closure to the hard bias layers thereby preventing flux leakage into the gap region. A non-magnetic layer must be included to prevent exchange coupling to the hard bias layers. In at least one embodiment the conductive leads are used to accomplish this.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: April 10, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Po Kang Wang, Moris Dovek, Jibin Geng, Tai Min
  • Patent number: 7203038
    Abstract: A magnetic head includes a seed layer structure comprising Al2O3, Ta, and NiFeCr seed layers. An antiparallel (AP) pinned layer structure is formed above the NiFeCr seed layer. A free layer is positioned above the AP pinned layer structure.
    Type: Grant
    Filed: August 10, 2005
    Date of Patent: April 10, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Mustafa Michael Pinarbasi
  • Patent number: 7203037
    Abstract: A method and apparatus for providing a dual current-perpendicular-to-plane (CPP) GMR sensor with improved top pinning is disclosed. In the passive regions of the sensor, a tri-level biasing layer is formed proximate to the top self-pinned layer. The tri-level biasing layer includes a first metal oxide layer, a layer of alpha-Fe2O3 and a second metal oxide layer. The pinning of the top self-pinned layer is enhanced by the layer of alpha-Fe2O3. The layer of alpha-Fe2O3 pins the top portion of the pinned layer by providing higher coercivity (HC) to the pinned layer.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: April 10, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7200035
    Abstract: A magneto-resistive memory comprising magneto-resistive memory cells is disclosed, comprising two pinned magnetic layers on one side of a free magnetic layer. The pinned magnetic layers are formed with anti-parallel magnetization orientations such that a net magnetic moment of the two layers is substantially zero. The influence of pinned magnetic layers on free magnetic layer magnetization orientations is substantially eliminated, allowing for increased predictability in switching behavior and increased write selectivity of memory cells.
    Type: Grant
    Filed: June 6, 2005
    Date of Patent: April 3, 2007
    Assignee: Micron Technology, Inc.
    Inventors: Theodore Zhu, Yong Lu, Anthony Arrott
  • Patent number: 7199983
    Abstract: A thin-film magnetic head is provided with an antiferromagnetic layer; a pinned layer comprising a first ferromagnetic layer, in contact with the antiferromagnetic layer, a second ferromagnetic layer having a direction of magnetization opposite from that of the first ferromagnetic layer, and a nonmagnetic spacer layer disposed between the first and second ferromagnetic layers; a free layer; and an intermediate layer disposed between the pinned layer and the free layer. The first ferromagnetic layer of the pinned layer is provided with a first layer comprising a ferromagnetic material, and a second layer, disposed between the first layer and the nonmagnetic spacer layer, comprising a ferromagnetic material. The first layer has a bulk scattering coefficient lower than that of the second layer.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: April 3, 2007
    Assignee: TDK Corporation
    Inventors: Sbiaa Rachid, Haruyuki Morita
  • Patent number: 7194796
    Abstract: A magnetic head and method for forming the same. Leads are added to a wafer stack having a free layer, a bias layer, and a spacer layer between the free layer and bias layer. A gap is formed between the leads. A protective layer is added to the wafer stack such that the gap is covered, as well as facing ends of the leads. Material is removed from at least one side area of the wafer stack using the protective layer as a mask. The protective layer is removed. A portion of the bias layer below the gap is processed for reducing a magnetic moment of the bias layer in the portion of the bias layer below the gap for forming a sensor in which magnetic moments of end portions of the free layer are pinned by magnetic moments of end portions of the bias layer, and preferably antiparallel thereto.
    Type: Grant
    Filed: July 10, 2003
    Date of Patent: March 27, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kim Y. Lee, Jih-Shiuan Luo
  • Patent number: 7196878
    Abstract: A spin valve (SV) sensor of the self-pinned type includes one or more compressive stress modification layers for reducing the likelihood that the pinning field will flip its direction. The spin valve sensor includes a capping layer formed over a spin valve structure which includes a free layer, an antiparallel (AP) self-pinned layer structure, and a spacer layer in between the free layer and the AP self-pinned layer structure. A compressive stress modification layer is formed above or below the capping layer, adjacent the AP self-pinned layer structure, or both. Preferably, the compressive stress modification layer is made of ruthenium (Ru) or other suitable material.
    Type: Grant
    Filed: February 27, 2004
    Date of Patent: March 27, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Ciaran Avram Fox, Hardayal Singh Gill, Prakash Kasiraj, Wen-Yaung Lee, Mustafa Michael Pinarbasi
  • Patent number: 7196879
    Abstract: A PtMn alloy film known as an antiferromagnetic material having excellent corrosion resistance is used for an antiferromagnetic layer. However, an exchange coupling magnetic field is decreased depending upon the conditions of crystal grain boundaries. Therefore, in the present invention, the crystal grain boundaries formed in an antiferromagnetic layer (PtMn alloy film) and the crystal grain boundaries formed in a ferromagnetic layer are made discontinuous in at least a portion of the interface between both layers. As a result, the antiferromagnetic layer can be appropriately transformed to an ordered lattice by heat treatment to obtain a larger exchange coupling magnetic field than a conventional element.
    Type: Grant
    Filed: December 16, 2005
    Date of Patent: March 27, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Patent number: 7193823
    Abstract: The present invention relates generally to the magnetic information storage technology, and particularly, to magnetic recording disc drives including a sensor having a giant magnetoresistance (GMR) based spin valve structure or a tunneling magnetoresistance(TMR) based tunnel junction magnetoresistance structure or magnetic random access memory device including a magnetic memory element(corresponding to a capacitor of DRAM) having a giant magnetoresistance (GMR) based spin valve structure or a tunneling magnetoresistance(TMR) based tunnel junction magnetoresistance structure. More particularly, the present invention relates to a spin valve magnetoresistive structure employed in the sensor of magnetic recording disc drive or tunnel junction magnetoresistive structure employed in the magnetic storage element of magnetic random access memory device.
    Type: Grant
    Filed: June 2, 2003
    Date of Patent: March 20, 2007
    Assignee: Korea University Foundation
    Inventors: Young Keun Kim, Jeong-Suk Park, Seong-Rae Lee
  • Patent number: 7190560
    Abstract: A magnetic head having a free layer, an antiparallel (AP) pinned layer structure spaced apart from the free layer, and a high coercivity structure positioned towards the AP pinned layer structure on an opposite side thereof relative to the free layer. The high coercivity structure pins a magnetic orientation of the AP pinned layer structure. The AP pinned layer structure includes at least two Fe-containing pinned layers having magnetic moments that are self-pinned antiparallel to each other, the pinned layers being separated by an AP coupling layer of Cr.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: March 13, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7190559
    Abstract: In the thin-film magnetic head of the present invention, the length of each of a pinned layer and an antiferromagnetic layer in their contact area in the depth direction from a surface facing a medium is longer than the length of a free layer in the same direction. When the length of the pinned layer in the depth direction is set longer as such, the direction of magnetization of the pinned layer can be restrained from being tilted by disturbances. Also, the pinned layer and the antiferromagnetic layer have the same length in their contact area in the MR height direction, so that the pinned layer is in contact with the antiferromagnetic layer throughout its length in the MR height direction, thus raising the exchange coupling force, whereby the inclination in the direction of magnetization can be suppressed more effectively.
    Type: Grant
    Filed: September 2, 2003
    Date of Patent: March 13, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Noriaki Kasahara
  • Patent number: 7190558
    Abstract: In a CPP element using a metal intermediate layer excellent in shot noise and response to high frequencies unlike a TMR element, its magnetoresistive effect film includes a magnetic layer mainly made of a half-metal exhibiting ferromagnetism, ferrimagnetism or antiferromagnetism, and largely variable in way of conduction in response to spin direction of electrons.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: March 13, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hitoshi Iwasaki, Katsuhiko Koui, Masatoshi Yoshikawa, Hiromi Yuasa, Hideaki Fukuzawa, Masashi Sahashi
  • Patent number: 7184248
    Abstract: A patterned, synthetic, longitudinally exchange biased GMR sensor is provided which has a narrow effective trackwidth and reduced side reading. The advantageous properties of the sensor are obtained by satisfying a novel relationship between the magnetizations (M) of the ferromagnetic free layer (F1) and the ferromagnetic biasing layer (F2) which enables the optimal thicknesses of those layers to be determined for a wide range of ferromagnetic materials and exchange coupling materials. The relationship to be satisfied is MF2/MF1=(Js+Jex)/Js, where Js is the synthetic coupling energy between F1 and F2 and Jex is the exchange energy between F2 and an overlaying antiferromagnetic pinning layer. An alternative embodiment omits the overlaying antiferromagnetic pinning layer which causes the relationship to become MF2/MF1=1.
    Type: Grant
    Filed: November 1, 2005
    Date of Patent: February 27, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Min Li, You Feng Zheng, Simon Liao, Kochan Ju
  • Patent number: 7178222
    Abstract: Insulating layers are formed on both sides of a multilayer film, and bias layers are formed in contact with at least portions of both end surfaces of a free magnetic layer. The bias layers are formed so as not to extend to the upper surface of the multilayer film. In this construction, a sensing current from electrode layers appropriately flows through the multilayer film, and a bias magnetic field can be supplied to the free magnetic layer from the bias layers through both side surfaces of the free magnetic layer. Furthermore, the magnetic domain structure of the free magnetic layer can be stabilized to permit an attempt to decrease instability of the reproduced waveform and Barkhausen noise.
    Type: Grant
    Filed: September 5, 2003
    Date of Patent: February 20, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventor: Naoya Hasegawa
  • Patent number: 7180715
    Abstract: A magnetic head having a free layer and an antiparallel (AP) pinned layer structure spaced apart from the free layer, the AP pinned layer structure including at least two AP-pinned layers having magnetic moments that are self-pinned antiparallel to each other, the AP-pinned layers being separated by an AP coupling layer. An easy axis of a first or both of the AP-pinned layers is oriented at an angle of at least 5° from the ABS along a plane of the first AP-pinned layer.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: February 20, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7180716
    Abstract: A method for fabricating a stitched CPP synthetic spin-valve sensor with in-stack stabilization of its free layer. The method can also be applied to the formation of a stitched tunneling magnetoresistive sensor. The free layer is strongly stabilized by magnetostatic coupling through the use of a longitudinal biasing formation that includes a ferromagnetic layer, denoted LBL, within the pillar portion of the sensor and a synthetic exchange coupled tri-layer within the stitched portion of the sensor. The tri-layer consists of two ferromagnetic layers, FM1 and FM2 separated by a coupling layer and magnetized longitudinally in antiparallel directions. A criterion for the magnetic thicknesses of the layers: [t(LBL)+t(FM1)]/t(FM2)=70/90 angstroms of CoFe insures a strong exchange coupling. The magnetization of the tri-layer is done in a low field anneal that does not disturb the previous magnetization of the ferromagnetic free layer.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: February 20, 2007
    Assignee: Headway Technologies, Inc.
    Inventors: Min Li, Youfeng Zheng, Kunliang Zhang, Simon Liao, Kochan Ju
  • Patent number: 7177120
    Abstract: A magnetic head assembly has a read head that includes a sensor wherein the sensor includes a self-pinned antiparallel (AP) pinned layer structure, a ferromagnetic free layer structure that has a magnetic moment that is free to rotate in response to signal fields and a spacer layer which is located between the free layer and AP pinned layer structures. The self-pinned AP pinned layer structure includes first and second antiparallel (AP) pinned layers, an antiparallel coupling (APC) layer located between and interfacing the first and second AP pinned layers wherein the second AP pinned layer is located between the first AP pinned layer and the spacer layer. The first AP pinned layer is composed of cobalt platinum chromium (CoPtCr).
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: February 13, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Mustafa Michael Pinarbasi
  • Patent number: 7171741
    Abstract: A Giant Magneto-Resistive (GMR) sensor (900) having Current Perpendicular to Plane (CPP) structure is formed providing an extended first pinned layer (914) as compared to second pinned layer (912) and free layer (910). Increased magnetoresistance changes, increased pinning strength, increased thermal stability, and decreased susceptibility to Electro-Static Discharge (ESD) events is realized by maintaining equivalent current densities through free layer (910) and second pinned layer (912), while decreasing the relative current density through first pinned layer (914).
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: February 6, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Hardayal Singh Gill
  • Patent number: 7173797
    Abstract: The thin-film magnetic head of the present invention is a CPP type head and comprises an anti-ferromagnetic layer, a pinned layer, a free layer, and a nonmagnetic layer disposed between the pinned layer and the free layer. The pinned layer is provided with a multilayer part comprising a first layer formed from Cu; a second layer formed from Cu and disposed closer to the free layer than is the first layer; and an intermediate layer. The intermediate layer is disposed between the first and second layers while in contact therewith, and is formed with a partly oxidized ferromagnetic layer.
    Type: Grant
    Filed: January 21, 2004
    Date of Patent: February 6, 2007
    Assignee: TDK Corporation
    Inventor: Rachid Sbiaa
  • Patent number: 7170725
    Abstract: A magnetic sensor is disclosed that is disposed between top and bottom magnetic shield layers, the sensor comprising: a nonferromagnetic layer disposed beneath the top shield layer; a magnetically soft layer disposed beneath the nonferromagnetic layer, the magnetically soft layer having a magnetization that rotates in response to an applied magnetic field; a ferromagnetic pinned layer disposed beneath the magnetically soft layer; an antiferromagnetic layer disposed beneath the ferromagnetic layer; and an aluminum-nitride seed layer disposed between the antiferromagnetic layer and the bottom shield layer. The aluminum-nitride seed layer decreases sense current shunting, increases pinning strength, increases magnetoresistance and/or increases yield.
    Type: Grant
    Filed: September 1, 2004
    Date of Patent: January 30, 2007
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Min Zhou, Chang-Man Park
  • Patent number: 7170724
    Abstract: A magnetic sensor comprises magnetoresistive elements and permanent magnet films, which are combined together to form GMR elements formed on a quartz substrate having a square shape, wherein the permanent magnet films are paired and connected to both ends of the magnetoresistive elements, so that an X-axis magnetic sensor and a Y-axis magnetic sensor are realized by adequately arranging the GMR elements relative to the four sides of the quartz substrate. Herein, the magnetization direction of the pinned layer of the magnetoresistive element forms a prescribed angle of 45° relative to the longitudinal direction of the magnetoresistive element or relative to the magnetization direction of the permanent magnet film. Thus, it is possible to reliably suppress offset variations of bridge connections of the GMR elements even when an intense magnetic field is applied; and it is therefore possible to noticeably improve the resistant characteristics to an intense magnetic field.
    Type: Grant
    Filed: October 16, 2003
    Date of Patent: January 30, 2007
    Assignee: Yamaha Corporation
    Inventors: Hideki Sato, Kokichi Aiso, Yukio Wakui
  • Patent number: 7167345
    Abstract: A magnetic sensor provided with a magnetoresistive effect element capable of stably maintaining a direction of magnetization in a magnetic domain of a free layer. The magnetic sensor includes a magnetoresistive effect element provided with narrow zonal portions including a pinned layer and a free layer. Disposed below both ends of the free layer are bias magnet films composed of a permanent magnet that applies to the free layer a bias magnetic field in a predetermined direction and an initializing coil that is disposed in the vicinity of the free layer and applies to the free layer a magnetic field having the direction same as that of the bias magnetic field by being energized under a predetermined condition.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: January 23, 2007
    Assignee: Yamaha Corporation
    Inventors: Toshiyuki Oohashi, Yukio Wakui
  • Patent number: 7164560
    Abstract: A spin-valve magnetoresistive thin film element comprises an antiferromagnetic layer and a pinned magnetic film. The pinned magnetic film contacts the antiferromagnetic layer, wherein a magnetizing direction is pinned by an exchange coupling magnetic field between the pinned magnetic layer and the antiferromagnetic layer. The spin-valve magnetoresistive thin film element further comprises a free magnetic layer and a nonmagnetic electrically conductive layer. The nonmagnetic electrically conductive layer is formed between the free magnetic layer and the pinned magnetic layer, wherein a magnetizing direction of said free magnetic layer is aligned so as to intersect with said magnetizing direction of said pinned magnetic film.
    Type: Grant
    Filed: July 22, 2003
    Date of Patent: January 16, 2007
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Naoya Hasegawa
  • Patent number: 7159304
    Abstract: Multiple thin films of spin-valve GMR sensor are formed in a trapezoidal cross-sectional shape by laminating an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer and a nonmagnetic protective layer on a lower insulated gap layer. The amount of etching of the lower insulated gap layer produced in the process of patterning the spin-valve giant magnetoresistive layers into the multiple thin films of spin-valve GMR sensor is 10 nm or less. Further, the angle ? which the tangent line of each side face of the multiple thin films to the middle line of the free magnetic layer in its thickness direction forms with respect to the middle line of the free magnetic layer becomes 45 degrees or more. This structure makes it possible to provide such a spin-valve giant magnetoresistive head that it meets the requirements for securing constant breakdown voltage and preventing instability of MR output voltage waveform.
    Type: Grant
    Filed: February 17, 2004
    Date of Patent: January 9, 2007
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Masatoshi Arasawa, Haruko Tanaka, Makoto Morijiri, Koichi Nishioka, Shuichi Kojima, Masayasu Kagawa
  • Patent number: 7155810
    Abstract: A GMR read head for a magnetic head, in which the hard bias layers are fabricated immediately next to the side edges of the free magnetic layer, and such that the midplane of the hard bias layer and the midplane of the free magnetic layer are approximately coplanar. The positioning of the hard bias layer is achieved by depositing a thick hard bias seed layer, followed by an ion milling step is to remove seed layer sidewall deposits. Thereafter, the hard bias layer is deposited on top of the thick seed layer. Alternatively, a first portion of the hard bias seed layer is deposited, followed by an ion milling step to remove sidewall deposits. A thin second portion of the seed layer is next deposited, and the hard bias layer is then deposited.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: January 2, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventor: Mustafa Michael Pinarbasi
  • Patent number: 7152304
    Abstract: Patterned, longitudinally and transversely antiferromagnetically exchange biased GMR sensors are provided which have narrow effective trackwidths and reduced side reading. The exchange biasing significantly reduces signals produced by the portion of the ferromagnetic free layer that is underneath the conducting leads while still providing a strong pinning field to maintain sensor stability. In the case of the transversely biased sensor, the magnetization of the free and biasing layers in the same direction as the pinned layer simplifies the fabrication process and permits the formation of thinner leads by eliminating the necessity for current shunting.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: December 26, 2006
    Assignee: Headway Technologies, Inc.
    Inventors: Cheng T. Horng, Min Li, Ru-Ying Tong, Yun-Fei Li, You Fong Zheng, Simon Liao, Kochan Ju, Cherng Chyi Han
  • Patent number: 7151653
    Abstract: The pinned layer structure in a self-pinned spin valve is deposited using a DC aligning field. The deposition of each of the Reference and Keeper layer in the pinned layer occurs within two different polarity DC aligning fields. Thus, a first portion of the Reference layer is deposited with a DC alignment field of a first polarity, i.e., either positive or negative, and a second portion of the Reference layer is deposited in a DC alignment field of opposite polarity. The Keeper layer is similarly deposited, with a first portion of the Keeper layer deposited in a first polarity DC alignment field and the second portion deposited in the opposite polarity DC alignment field. By splitting the deposition of the Reference and Keeper layers into portions using DC aligning fields the pinned layer structure is highly repeatable while providing a good thickness uniformity of the structure.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: December 19, 2006
    Assignee: Hitachi Global Technologies Netherlands B.V.
    Inventors: Daniele Mauri, Alexander M. Zeltser
  • Patent number: 7151652
    Abstract: A top-pinned magnetoresistive device includes a free ferromagnetic layer; a spacer layer on the free layer; and a pinned ferromagnetic layer on the spacer layer. At least one interface property at an upper surface of the pinned layer is adjusted during fabrication of the magnetoresistive device.
    Type: Grant
    Filed: June 18, 2003
    Date of Patent: December 19, 2006
    Assignee: Hewett-Packard Development Company, L.P.
    Inventors: Janice H. Nickel, Manish Sharma
  • Patent number: 7150093
    Abstract: A method of initializing a magnetic sensor and storage system implementing such a magnetic sensor. The method includes heating and cooling dual antiferromagnetic layers in the presence of a magnetic field.
    Type: Grant
    Filed: December 22, 2003
    Date of Patent: December 19, 2006
    Assignee: International Business Machines Corporation
    Inventor: Robert S. Beach
  • Patent number: 7149062
    Abstract: A magnetic head having a spin valve sensor that is fabricated utilizing an Al2O3, NiMn0, Si seed layer upon which a PtMn spin valve sensor layer structure is subsequently fabricated. In the preferred embodiment, the Si layer has a thickness of approximately 20 ? and the PtMn layer has a thickness of approximately 120 ?. An alternative fabrication process of the Si layer includes the overdeposition of the layer to a first thickness of from 15 ? to 45 ? followed by the etching back of the seed layer of approximately 5 ? to approximately 15 ? to its desired final thickness of approximately 20 ?. The Si layer results in an improved crystal structure to the subsequently fabricated PtMn and other spin valve sensor layers, such that the fabricated spin valve is thinner and exhibits increased ?R/R and reduced coercivity.
    Type: Grant
    Filed: February 26, 2002
    Date of Patent: December 12, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Mustafa Pinarbasi, Patrick Rush Webb
  • Patent number: 7145755
    Abstract: In one illustrative example of the invention, a spin valve sensor includes a free layer structure; an antiparallel (AP) pinned layer structure; and a non-magnetic electrically conductive spacer layer in between the free layer structure and the AP pinned layer structure. The AP pinned layer structure includes a first AP pinned layer; a second AP pinned layer; and an antiparallel coupling (APC) layer formed between the first and the second AP pinned layer. One of the first and the second AP pinned layers consists of cobalt and the other one includes cobalt-iron. The pure cobalt may be provided in the first AP pinned layer or the second AP pinned layer. Advantageously, the use of cobalt in one of the AP pinned layers increases the ?r/R of the spin valve sensor.
    Type: Grant
    Filed: September 30, 2003
    Date of Patent: December 5, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Mustafa Michael Pinarbasi
  • Patent number: 7142399
    Abstract: An exchange coupling film including an antiferromagnetic layer and a ferromagnetic layer in contact with the antiferromagnetic layer so as to generate an exchange coupling magnetic field is provided. A PtMn alloy is used as the material of the antiferromagnetic layer. Crystal planes of the antiferromagnetic layer and the ferromagnetic layer preferentially aligned parallel to the interface are crystallographically identical and crystallographically identical axes lying in these crystal planes are oriented, at least partly, in different directions between the antiferromagnetic layer and the ferromagnetic layer. Thus, a proper order transformation occurs in the antiferromagnetic layer as a result of heat treatment and an increased exchange coupling magnetic field can be obtained.
    Type: Grant
    Filed: July 9, 2001
    Date of Patent: November 28, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito