Having One Film Pinned (e.g., Spin Valve) Patents (Class 360/324.1)
  • Patent number: 6828260
    Abstract: A method of treating an electrically non-conductive tunnel barrier layer through an overlayer of a tunnel junction device with ultra-violet light is disclosed. The method includes irradiating a tunnel barrier layer with ultra-violet light through at least one overlayer that covers the tunnel barrier layer to activate oxygen or nitrogen atoms disposed in the barrier layer so that those atoms will react with a target material of the tunnel barrier layer to form a uniformly oxidized or nitridized tunnel barrier layer having minimal or no defects therein and/or a desired breakdown voltage. The ultra violet light can irradiate the tunnel barrier layer during or after the formation of the overlayer. Heat can be applied before, during, or after the irradiation step to increase the activation rate and to further reduce defects. The method is applicable to any tunnel junction device including a magnetic field sensitive memory device such as a MRAM.
    Type: Grant
    Filed: October 29, 2002
    Date of Patent: December 7, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Manish Sharma, Trueman H Denny, III
  • Patent number: 6829121
    Abstract: A magnetoresistive film includes a nonmagnetic film, and a structure in which magnetic films are formed on the two sides of the nonmagnetic film. At least one of the magnetic films is a perpendicular magnetization film. A magnetic film whose easy axis of magnetization is inclined from a direction perpendicular to the film surface is formed at a position where the magnetic film contacts the perpendicular magnetization film but does not contact the nonmagnetic film. A memory, magnetic element, magnetoresistive element, and magnetic element manufacturing method are also disclosed.
    Type: Grant
    Filed: April 2, 2002
    Date of Patent: December 7, 2004
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Ikeda, Akio Koganei, Kazuhisa Okano
  • Publication number: 20040233587
    Abstract: A magnetic sensor using efficient injection of spin polarized electrons at room temperature can be fabricated by forming a semiconductor layer sandwiched between ferromagnets and forming &dgr;-doped layers between the semiconductor layer and the ferromagnets. A sensing method applies a magnetic field to be measured to the semiconductor layer and observes the conductivity of the sensor. The sensing techniques can achieve high magneto-sensitivity and very high operating speed, which in turn provides ultra fast and sensitive magnetic sensors.
    Type: Application
    Filed: June 28, 2004
    Publication date: November 25, 2004
    Inventors: Viatcheslav V. Osipov, Alexandre M. Bratkovski
  • Publication number: 20040233584
    Abstract: Increasing the output signal from CPP GMR devices by increasing the read current has not previously been considered an option because it would make the device run too hot. This problem has been overcome by using, for the upper and lower leads, materials that differ significantly in their thermoelectric powers. Thus, when DC is passed through the device, from − to +TEP leads, hot and cold junctions are formed and heat is transferred from the micro-device into the leads, resulting in a net local cooling of the device which enables it to operate at higher power. For a GMR device, this translates to a larger output voltage, making it easier, more sensitive, and more reliable to use.
    Type: Application
    Filed: May 22, 2003
    Publication date: November 25, 2004
    Applicant: Headway Technologies, Inc.
    Inventors: Yue Liu, Kochan Ju, Jei Wei Chang, Julie Chen
  • Patent number: 6820322
    Abstract: A method makes a spin valve sensor of a magnetic read head which includes the steps of forming a ferromagnetic pinned layer structure that has a magnetic moment, forming a pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure, forming a free layer structure, forming a nonmagnetic electrically conductive spacer layer between the free layer and the pinned layer structure and the forming of the free layer structure including the step of sputter depositing at least a first free layer composed of cobalt iron directly on the spacer layer in a nitrogen atmosphere.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: November 23, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Mustafa Pinarbasi
  • Publication number: 20040228045
    Abstract: A CPP giant magnetoresistive element includes a multilayer film including a lower pinned magnetic layer having a laminated ferrimagnetic structure including a lower first pinned magnetic sublayer, a lower nonmagnetic intermediate sublayer, and a lower second pinned magnetic sublayer; a lower nonmagnetic layer; a free magnetic layer; an upper nonmagnetic layer; and an upper pinned magnetic layer having a laminated ferrimagnetic structure including an upper second pinned magnetic sublayer, an upper nonmagnetic intermediate sublayer, and an upper first pinned magnetic sublayer disposed in that order. Each of the free magnetic layer and the lower and upper second pinned magnetic sublayers is composed of a NiFeX alloy or NiFeCoX alloy, X being an element which decreases the saturation magnetization of a NiFe or NiFeCo base.
    Type: Application
    Filed: May 10, 2004
    Publication date: November 18, 2004
    Applicant: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Publication number: 20040228044
    Abstract: A fixed magnetic layer contains a first magnetic layer formed on a non-magnetic metal layer. The non-magnetic metal layer is composed of an X-Mn alloy (where X is selected from Pt, Pd, Ir, Rh, Ru, Os, Ni, and Fe). While atoms forming the first magnetic layer and atoms forming the non-magnetic metal layer are being aligned with each other, strains are generated in the individual crystal structures. By generating the strain in the crystal structure of the first magnetic layer, the magnetostriction constant &lgr; is increased. As a result, a magnetic sensor having a large magnetoelastic effect can be provided.
    Type: Application
    Filed: February 20, 2004
    Publication date: November 18, 2004
    Applicant: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu, Masamichi Saito, Yosuke Ide
  • Publication number: 20040223266
    Abstract: A method for forming an NiCr seed layer based bottom spin valve sensor element having a synthetic antiferromagnet pinned (SyAP) layer and a capping layer comprising either a single specularly reflecting nano-oxide layer (NOL) or a bi-layer comprising a non-metallic layer and a specularly reflecting nano-oxide layer and the sensor element so formed. The method of producing these sensor elements provides elements having higher GMR ratios and lower resistances than elements of the prior art.
    Type: Application
    Filed: May 28, 2004
    Publication date: November 11, 2004
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventor: Min Li
  • Patent number: 6816346
    Abstract: As the dimensions of spin valve heads continue to be reduced, a number of difficulties are being encountered. One such is with the longitudinal bias when an external magnetic field can cause reversal of the hard magnet, thereby causing a hysteric response by the head. This coercivity reduction becomes more severe as the hard magnet becomes thinner. This problem has been overcome by inserting a decoupling layer between the antiferromagnetic layer that is used to stabilize the pinned layer of the spin valve itself and the soft ferromagnetic layer that is used for longitudinal biasing. This soft ferromagnetic layer is pinned by a second antiferromagnetic layer deposited on it on its far side away from the first antiferromagnetic layer. The presence of the decoupling layer ensures that the magnetization of the soft layer is determined only by the second antiferromagnetic layer. The inclusion of said decoupling layer allows more latitude in etch depth control during manufacturing.
    Type: Grant
    Filed: March 2, 2004
    Date of Patent: November 9, 2004
    Assignee: Headway Technologies, Inc.
    Inventors: You Feng Zheng, Kochan Ju, Cheng T. Horng, Simon Liao, Ru Ying Tong
  • Publication number: 20040207959
    Abstract: A CPP giant magnetoresistive head includes lower and upper shield layers; and a giant magnetoresistive element disposed between the upper and lower shield layers and comprising a pinned magnetic layer, a free magnetic layer, and a nonmagnetic layer disposed between the pinned magnetic layer and the free magnetic layer. Large-area nonmagnetic metal films are provided directly above the lower shield layer and below the upper shield layer making direct contact with and having larger areas than the pinned magnetic layer and the free magnetic layer, respectively. An antiferromagnetic layer is provided in the rear of the giant magnetoresistive element in the height direction, for pinning the magnetization direction of the pinned magnetic layer.
    Type: Application
    Filed: April 13, 2004
    Publication date: October 21, 2004
    Applicant: Alps Electric Co., Ltd.
    Inventor: Masamichi Saito
  • Publication number: 20040207960
    Abstract: A CPP giant magnetoresistive head includes lower and upper shield layers, and a giant magnetoresistive element disposed between the upper and lower shield layers and including a pinned magnetic layer, a free magnetic layer and a nonmagnetic layer disposed between the pinned magnetic layer and the free magnetic layer. In the CPP giant magnetoresistive head, the pinned magnetic layer extends to the rear of the nonmagnetic layer and the free magnetic layer in the height direction, and the dimension of the pinned magnetic layer in the height direction is larger than that in the track width direction. Also, the pinned magnetic layer comprises a magnetic material having a positive magnetostriction constant or a magnetic material having high coercive force, and the end of the pinned magnetic layer is exposed at a surface facing a recording medium.
    Type: Application
    Filed: April 13, 2004
    Publication date: October 21, 2004
    Applicant: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Yoshihiro Nishiyama, Yosuke Ide, Eiji Umetsu, Naoya Hasegawa, Yasuo Hayakawa
  • Publication number: 20040201929
    Abstract: A magnetoresistance effect element comprises: a magnetoresistance effect film, a pair of electrodes, and a phase separation layer. The magnetoresistance effect film includes a first ferromagnetic layer whose direction of magnetization is pinned substantially in one direction, a second ferromagnetic layer whose direction of magnetization changes in response to an external magnetic field, and an intermediate layer provided between the first and second ferromagnetic layers. The pair of electrodes are electrically coupled to the magnetoresistance effect film and configured to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film. The phase separation layer is provided between the pair of electrodes. The phase separation layer has a first phase and a second phase formed by a phase separation in a solid phase from an alloy including a plurality of elements.
    Type: Application
    Filed: September 11, 2003
    Publication date: October 14, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Susumu Hashimoto, Katsuhiko Koui, Masashi Sahashi, Hitoshi Iwasaki
  • Publication number: 20040201930
    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 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: Application
    Filed: February 26, 2004
    Publication date: October 14, 2004
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi
  • Publication number: 20040194292
    Abstract: A method of manufacturing a magnetic tunnel junction device, in which a stack (1) comprising two electrode layers (3, 7) and a barrier layer (5) extending in between is formed. One of the electrode layers is structured by means of etching, in which, during etching, a part of this layer is made thinner by removing material until a rest layer (7r) remains. This rest layer is subsequently removed by means of physical etching, in which at least substantially charged particles have a motion energy which is between the sputtering threshold of the magnetic material of the rest layer and the sputtering threshold of the non-magnetic material of the barrier layer. In the relevant method, it is prevented that the electrode layer which is not to be structured is detrimentally influenced during structuring of the other electrode layer.
    Type: Application
    Filed: April 20, 2004
    Publication date: October 7, 2004
    Inventor: Joannes Baptist Adrianus Dionisius Van Zon
  • Publication number: 20040190204
    Abstract: A magnetoresistive element includes a magnetoresistive film having a magnetization pinned layer, a magnetization free layer, and a nonmagnetic intermediate layer. A magnetization direction of the magnetization pinned layer is substantially fixed in an external magnetic field, a magnetization direction of the magnetization free layer is configured to change in the external magnetic field, and the nonmagnetic intermediate layer formed between the magnetization pinned layer and the magnetization free layer and has a stacked structure of a first non-metallic intermediate layer/a metal intermediate layer/a second non-metallic intermediate layer. The magnetoresistive element also includes a pair of electrodes coupled to the magnetoresistive film and is configured to provide a current in a direction substantially perpendicular to a surface of the magnetoresistive film.
    Type: Application
    Filed: December 23, 2003
    Publication date: September 30, 2004
    Inventors: Masatoshi Yoshikawa, Masayuki Takagishi, Tomomi Funayama, Kohichi Tateyama, Hitoshi Iwasaki, Hideaki Fukuzawa
  • Publication number: 20040190205
    Abstract: The present invention provides a thin film magnetic head and a method of manufacturing the same in which a magnetic sensitive layer can be excellently formed as a single magnetic domain while adapting the head to higher recording density and, further, which can display a higher resistance change rate. First magnetic domain control parts sandwich an upper layer part including a magnetic sensitive layer having first width W1, and second magnetic domain control parts sandwich a lower layer part having second width W2 which is larger than the first width W1. With such a configuration, while narrowing the magnetic sensitive layer, a vertical bias magnetic field having both sufficient intensity and uniformity can be applied to the magnetic sensitive layer. As a result, it can be promoted to form the magnetic sensitive layer as a single magnetic domain while adapting the head to higher recording density, so that reading operation can be performed more stably.
    Type: Application
    Filed: March 26, 2004
    Publication date: September 30, 2004
    Applicant: TDK CORPORATION
    Inventor: Daisuke Miyauchi
  • Patent number: 6798625
    Abstract: The present invention provides a spin-valve magnetoresistance sensor in which are formed, on top of the substrate, free layers, and pinned layers, enclosing a nonmagnetic spacer layer, and an antiferromagnetic layer adjacent to the pinned layers. The sensor is also equipped with a back layer including at least two nonmagnetic metal layers adjacent to the free layers on the side of the free layers opposite the nonmagnetic spacer layer. The back layer has at least one nonmagnetic metal layer of Cu with high electrical conductivity, preferably formed adjacent to the free layers, as for example in a two-layer structure of Cu and Ru or a three-layer structure Ru/Cu/Ru. In addition to a high read output, fluctuations in Hint with the film thickness of the back layer can be suppressed and sensor characteristics stabilized, and high recording densities can be realized.
    Type: Grant
    Filed: September 26, 2000
    Date of Patent: September 28, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Masaki Ueno, Kiyotaka Tabuchi, Tatsuo Sawasaki, Hiroshi Nishida, Kazuhiro Mizukami, Fuminori Hikami
  • Patent number: 6798624
    Abstract: A magnetization sensor for sensing write field characteristic of a perpendicular or longitudinal recording head such as may be used with a disc drive, and a method of manufacture therefor are disclosed. The sensor can be manufactured concurrently with the write head and incorporated therein. The magnetization sensor comprises a non-magnetic layer separating a hard magnetic layer and a soft magnetic layer, with electrical leads to provide a biasing and sensing current. The magnetization sensor can be either a giant magnetoresistive element or a tunneling magnetoresistive element, depending upon the non-magnetic layer used in the construction of the device.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: September 28, 2004
    Assignee: Seagate Technology LLC
    Inventors: Mark W. Covington, Thomas M. Crawford
  • Publication number: 20040184198
    Abstract: A highly reliable magnetic recording/reproducing apparatus is provided. In the magnetic recording/reproducing apparatus, a spin-valve film is used as a magnetic sensor element for detecting magnetic signals. By defining the corrosion potential of this spin-valve film, and further by specifying the residual magnetization of a magnetic recording medium used as well as the product of the residual magnetization and the thickness of the magnetic layer to a range that is numerically optimal, the occurrence of corrosion on the surface of a magnetoresistive head that contacts the medium is prevented, and the occurrence of electromagnetic discharge is avoided. Further, by numerically specifying the surface resistivity of the metal magnetic thin film of the magnetic recording medium, as well as the roughness of the surface on which the metal magnetic thin film is formed, electrostatic discharge preventing effects and wear resistance are improved.
    Type: Application
    Filed: December 12, 2003
    Publication date: September 23, 2004
    Inventors: Hiroki Tetsukawa, Yutaka Soda
  • Publication number: 20040184197
    Abstract: A current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) sensor stack and its method of fabrication are provided, wherein the parasitic resistance of the high-resistance antiferromagnetic (AFM) pinning layer is effectively reduced by enlarging its surface area and separating it from the remainder of the sensor stack by an equal area, contiguous, thin, highly conductive ferromagnetic layer, the current channeling (CCL) layer. The magnetic properties and increased current carrying capacity of the CCL allows the AFM pinning layer to effectively couple to the pinned layer while eliminating the effect of its high resistance on the sensor sensitivity as measured by the GMR ratio, &Dgr;R/R. In another embodiment, the effects of a CCL are provided by the synthetic pinned layer of a synthetic GMR formation, wherein the spacer and free layers of the GMR are reduced in width relative to the synthetic pinned layer.
    Type: Application
    Filed: March 19, 2003
    Publication date: September 23, 2004
    Applicant: Headway Technologies, Inc.
    Inventors: Youfeng Zheng, Kochan Ju, Otto Voegeli
  • Patent number: 6795279
    Abstract: This invention presents a method and structure for magnetic spin valves. The spin valve structure includes a first ferromagnetic layer separated from a second ferromagnetic layer by a non-magnetic layer. The spin valve structure also includes a first specular scattering layer separated from a second specular scattering layer by the first ferromagnetic layer, the non-magnetic layer, and the second ferromagnetic layer. The first ferromagnetic layer can include a free layer and the non-magnetic layer can include a spacer layer. The second ferromagnetic layer can include a pinned layer or a reference layer. The specular scattering layers can include a material such as Y2O3, HfO2, MgO, Al2O3, NiO, Fe2O3, and Fe3O4. The specular scattering layers can also be used in a SAF structure. In the SAF structure, the antiferromagnetic coupling material can be co-deposited with the second specular scattering layer.
    Type: Grant
    Filed: January 9, 2004
    Date of Patent: September 21, 2004
    Assignee: Seagate Technology LLC
    Inventors: Eric W. Singleton, Kristin Joy Duxstad, Michael B. Hintz
  • Patent number: 6788499
    Abstract: A spin valve sensor with insulating and conductive seed layers is provided. The sensor comprising Al2O3/Ni—Cr—Fe/Ni—Fe/Co—Fe/Cu/Co—Fe/Ru/Co—Fe/Pt—Mn films is formed by depositing an insulating Al2O3 seed layer in a first chamber by reactively pulsed DC magnetron sputtering, depositing a conducting Ni—Cr—Fe seed layer and a ferromagnetic Ni—Fe free layer in a second chamber by ion beam sputtering, and then forming the remainder of the spin valve sensor in a third chamber by DC magnetron sputtering.
    Type: Grant
    Filed: May 19, 2003
    Date of Patent: September 7, 2004
    Assignee: International Business Machines Corporation
    Inventors: Tsann Lin, Daniele Mauri
  • Publication number: 20040169963
    Abstract: A magnetoresistance effect element includes a first ferromagnetic layer (1), insulating layer (3) overlying the first ferromagnetic layer, and second ferromagnetic layer (2) overlying the insulating layer. The insulating layer has formed a through hole (A) having an opening width not larger than 20 nm, and the first and second ferromagnetic layers are connected to each other via the through hole.
    Type: Application
    Filed: March 10, 2004
    Publication date: September 2, 2004
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shiho Okuno, Yuichi Ohsawa, Shigeru Haneda, Yuzo Kamiguchi, Tatsuya Kishi
  • Publication number: 20040169962
    Abstract: As the dimensions of spin valve heads continue to be reduced, a number of difficulties are being encountered. One such is with the longitudinal bias when an external magnetic field can cause reversal of the hard magnet, thereby causing a hysteric response by the head. This coercivity reduction becomes more severe as the hard magnet becomes thinner. This problem has been overcome by inserting a decoupling layer between the antiferromagnetic layer that is used to stabilize the pinned layer of the spin valve itself and the soft ferromagnetic layer that is used for longitudinal biasing. This soft ferromagnetic layer is pinned by a second antiferromagnetic layer deposited on it on its far side away from the first antiferromagnetic layer. The presence of the decoupling layer ensures that the magnetization of the soft layer is determined only by the second antiferromagnetic layer. The inclusion of said decoupling layer allows more latitude in etch depth control during manufacturing.
    Type: Application
    Filed: March 2, 2004
    Publication date: September 2, 2004
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: You Feng Zheng, Kochan Ju, Cheng T. Horng, Simon Liao, Ru Ying Tong
  • Patent number: 6785101
    Abstract: The first and second side surfaces of either a bottom spin valve sensor or a top spin valve sensor are notched so as to enable a reduction in the magnetoresistive coefficient of side portions of the sensor beyond the track width region thereby minimizing side reading by the sensor. The first and second notches of the spin valve sensor are then filled with layers in various embodiments of the invention to complete the spin valve sensor.
    Type: Grant
    Filed: July 12, 2001
    Date of Patent: August 31, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Patrick Rush Webb, Mustafa Pinarbasi, Richard Hsiao, Hardayal Singh Gill
  • Publication number: 20040165319
    Abstract: A spin valve GMR sensor configured in a bridge configuration is provided. The bridge includes two spin valve element pairs. The spin valve elements include a free layer, a space layer, a pinning layer, and a bias layer. The bias layer includes a first bias layer and a second bias layer. The first and second spin valve element pairs are formed on separate metal layers and a current pulse is applied to the metal layers, which sets the direction of magnetization in the pinning layer of the first pair of spin valve elements to be antiparallel to the direction of magnetization in the pinning layer of the second pair of spin valve elements. The same effect can be accomplished by making the pinning layer substantially thicker than the second bias layer in the first spin valve element pair and the pinning layer is substantially thinner than the second bias layer in the second spin valve element pair and applying a magnetic field to the first and the second spin valve element pairs.
    Type: Application
    Filed: February 20, 2003
    Publication date: August 26, 2004
    Applicant: Honeywell International Inc.
    Inventors: Hong Wan, Lakshman S. Withanawasam
  • Patent number: 6781801
    Abstract: A tunneling magnetoresistive (TMR) stack configured to operate in a current-perpendicular-to-plane (CPP) mode has a plurality of layers including a spin valve and a barrier layer. The spin valve is used to inject a spin polarized sense current into the barrier layer for increasing a magnetoresistive (MR) ratio of the TMR stack.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: August 24, 2004
    Assignee: Seagate Technology LLC
    Inventors: Olle Gunnar Heinonen, Declan Macken
  • Patent number: 6779248
    Abstract: In bottom spin valves of the lead overlay type the longitudinal bias field that stabilizes the device tends to fall off well before the gap is reached. This problem has been overcome by providing a manufacturing process that includes inserting an additional antiferromagnetic layer between the hard bias plugs and the overlaid leads. This additional antiferromagnetic layer and the lead layer are etched in the same operation to define the read gap, eliminating the possibility of misalignment between them. The extra antiferromagnetic layer is also longitudinally biased so there is no falloff in bias strength before the edge of the gap is reached. A process for manufacturing the device is also described.
    Type: Grant
    Filed: March 7, 2002
    Date of Patent: August 24, 2004
    Assignee: Headway Technologies, Inc.
    Inventors: Moris M. Dovek, Tai Min
  • Publication number: 20040160810
    Abstract: A magnetic random access memory device including a pinned layer having a diffusion barrier, a sense layer, and a tunnel barrier to electrically couple the pinned layer to the sense layer. A method for forming a magnetic random access memory device including forming, on a substrate, a sense layer, forming a tunnel barrier on the sense layer, forming a pinned layer on the tunnel barrier, where the pinned layer includes a diffusion barrier to stop manganese atoms from diffusing to the interface of the tunnel barrier, and annealing the substrate, the sense layer, the tunnel barrier and the pinned layer. The diffusion barrier can include a native oxide having a thickness up to about seven angstroms or an aluminum oxide having a thickness up to about seven angstroms.
    Type: Application
    Filed: February 18, 2003
    Publication date: August 19, 2004
    Applicant: Micron Technology, Inc.
    Inventors: James G. Deak, Maciej M. Kowalewski
  • Publication number: 20040160706
    Abstract: A slider (34) for reading data from a disk surface (80), the slider (80) including a magneto-resistive head (36). The head (36) includes a transducer (58) having a stack of layers (59), each layer (62,66,70,74) having a proximal end (64,68,72,76) proximal to the disk surface, and a pair of electrical leads (82), connected to the transducer (58), each one of the electrical leads (82) also having a proximal end (83) proximal to the disk surface (80). At least one of the proximal ends (83) of the electrical leads (82) and the layers (66) is recessed to provide one or more recessed areas (92). The recessed areas (92) are then filled with protective material (94) to a depth such that when the layer of protective material (48) is worn from the proximal ends (64,68,72,76,83) by burnishing by the disk surface (80), protective material (94) still remains in the recessed areas (92).
    Type: Application
    Filed: February 20, 2004
    Publication date: August 19, 2004
    Inventors: Dallas W. Meyer, Tien-Chih Lin, Michael A. Stacy
  • Patent number: 6773515
    Abstract: A method for forming an NiCr seed layer based bottom spin valve sensor element having a synthetic antiferromagnet pinned (SyAP) layer and a capping layer comprising either a single specularly reflecting nano-oxide layer (NOL) or a bi-layer comprising a non-metallic layer and a specularly reflecting nano-oxide layer and the sensor element so formed. The method of producing these sensor elements provides elements having higher GMR ratios and lower resistances than elements of the prior art.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: August 10, 2004
    Assignee: Headway Technologies, Inc.
    Inventors: Min Li, Simon H. Liao, Masashi Sano, Kiyoshi Noguchi, Kochan Ju, Cheng T. Horng
  • Patent number: 6775110
    Abstract: A magnetoresistance effect device has the basic structure of substrate/sublayer/NiFe layer/CoFe layer/non-magnetic layer/fixed magnetic layer/antiferromagnetic layer. The sublayer may be Ta at a film thickness of not less than 0.2 nm but less than 3.0 nm, or Hf at a film thickness of not less than 0.2 nm but not greater than 1.5 nm, or Zr at a film thickness of not less than 0.2 nm but not greater than 2.5 nm. It is permissible to use only an NiFe layer instead of the NiFe layer/CoFe layer.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: August 10, 2004
    Assignee: TDK Corporation
    Inventors: Kazuhiko Hayashi, Shigeru Mori, Masafumi Nakada
  • Publication number: 20040150921
    Abstract: A magnetic head has a base, and a magneto-resistive device supported by the base. The magneto-resistive device includes a magneto-resistive layer formed on one surface side of the base, and a first film. The first film is formed to be in contact with an effective region effectively involved in detection of magnetism in the magneto-resistive layer on both sides or one side of the effective region in a track width direction without overlapping with the effective region. The track width direction is substantially parallel to a film surface of the magneto-resistive layer. The first film is a single-layer film or a multiple-layer film. The first film includes a soft magnetic layer which does not form part of a layer for applying a biasing magnetic field to the free layer. The soft magnetic layer contributes to a reduction in side reading.
    Type: Application
    Filed: December 29, 2003
    Publication date: August 5, 2004
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Tetsuya Kuwashima
  • Patent number: 6770382
    Abstract: A Spin Valve GMR and Spin Filter SVGMR configuration where in the first embodiment an important buffer layer is composed of an metal oxide having a crystal lattice constant that is close the 1st FM free layer's crystal lattice constant and has the same crystal structure (e.g., FCC, BCC, etc.). The metal oxide buffer layer enhances the specular scattering. The spin valve giant magnetoresistance (SVGMR) sensor comprises: a seed layer over the substrate. An important metal oxide buffer layer (buffer layer) over the seed layer. The metal oxide layer preferably is comprised of NiO or alpha-Fe2O3. A free ferromagnetic layer over the metal oxide layer. A non-magnetic conductor spacer layer over the free ferromagnetic layer. A pinned ferromagnetic layer (2nd FM pinned) over the non-magnetic conductor spacer layer and a pinning material layer over the pinned ferromagnetic layer. In the second embodiment, a high conductivity layer (HCL) is formed over the buffer layer to create a spin filter -SVGMR.
    Type: Grant
    Filed: November 22, 1999
    Date of Patent: August 3, 2004
    Assignee: Headway Technologies, Inc.
    Inventors: Jei-Wei Chang, Bernard Dieny, Mao-Min Chen, Cheng Horng, Kochan Ju, Simon Liao
  • Patent number: 6767655
    Abstract: The present invention provides a vertical current-type magneto-resistive element. The element includes an intermediate layer and a pair of magnetic layers sandwiching the intermediate layer, and at least one of a free magnetic layer and a pinned magnetic layer is a multilayer film including at least one non-magnetic layer and magnetic layers sandwiching the non-magnetic layer. The element area defined by the area of the intermediate layer through which current flows perpendicular to the film is not larger than 1000 &mgr;m2.
    Type: Grant
    Filed: August 16, 2001
    Date of Patent: July 27, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masayoshi Hiramoto, Nozomu Matukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
  • Publication number: 20040141258
    Abstract: This invention presents a method and structure for magnetic spin valves. The spin valve structure includes a first ferromagnetic layer separated from a second ferromagnetic layer by a non-magnetic layer. The spin valve structure also includes a first specular scattering layer separated from a second specular scattering layer by the first ferromagnetic layer, the non-magnetic layer, and the second ferromagnetic layer. The first ferromagnetic layer can include a free layer and the non-magnetic layer can include a spacer layer. The second ferromagnetic layer can include a pinned layer or a reference layer. The specular scattering layers can include a material such as Y2O3, HfO2, MgO, Al2O3, NiO, Fe2O3, and Fe3O4. The specular scattering layers can also be used in a SAF structure. In the SAF structure, the antiferromagnetic coupling material can be co-deposited with the second specular scattering layer.
    Type: Application
    Filed: January 9, 2004
    Publication date: July 22, 2004
    Applicant: Seagate Technology LLC
    Inventors: Eric W. Singleton, Kristin Joy Duxstad, Michael B. Hintz
  • Patent number: 6762915
    Abstract: A magnetoresistive stack for use in a magnetic read head has a plurality of layers including a ferromagnetic free layer, a ferromagnetic pinned layer, and an antiferromagnetic pinning layer. The pinned layer and pinning layer each have a greater number of structural grains than the free layer, which decreases a fluctuation of magnetization in the magnetoresistive stack without decreasing a spatial resolution of the magnetoresistive stack.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: July 13, 2004
    Assignee: Seagate Technology LLC
    Inventors: Taras Grigoryevich Pokhil, Olle Gunnar Heinonen, Chunhong Hou
  • Patent number: 6759120
    Abstract: There is disclosed a magnetoresistive film in which increase of a coupling field accompanying thickness reduction of a middle layer is inhibited. The magnetoresistive film is a multilayered film including a pinned layer 3 having magnetization whose direction is fixed, a nonmagnetic middle layer 4 formed on the pinned layer, and a free layer 5 formed on the middle layer and provided with magnetization whose direction changes in accordance with an external magnetic field, the magnetoresistive film indicates a magnitude of resistance in accordance with an angle formed by the magnetization direction of the pinned layer and the magnetization direction of the free layer, and a copper oxide layer 7 of an oxide including a copper element is formed directly on the free layer, or on the free layer via an oxide layer 6 of a material fabricated by oxidizing a material constituting the free layer.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: July 6, 2004
    Assignee: Fujitsu Limited
    Inventors: Hong Jongill, Kenichi Aoshima, Kenji Noma, Junichi Kane, Hitoshi Kanai
  • Patent number: 6756128
    Abstract: A low resistance magnetic tunnel junction device, such as a memory cell in a nonvolatile magnetic random access memory (MRAM) array or a magnetoresistive read head in a magnetic recording disk drive, has a titanium oxynitride (TiOxNy) layer as the single-layer tunnel barrier or as one of the layers in a bilayer tunnel barrier. In a bilayer barrier the other barrier layer is an oxide or nitride of Al, Si, Mg, Ta, [[Si]] and Y, such as Al2O3, AlN, Si3N4, MgO, Ta2O5, TiO2, or Y2O3. The Ti barrier material can be alloyed with other known metals, such as Al and Mg, to produce barriers with TiAlOxNy and TiMgOxNy compositions.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: June 29, 2004
    Assignee: International Business Machines Corporation
    Inventors: Matthew J. Carey, Bruce A. Gurney, Yongho Ju
  • Patent number: 6757143
    Abstract: In a magnetoresistive effect element, at least one of electrodes for supplying a current perpendicularly to the film plane of a magnetoresistive effect film is narrower than the distance between bias-applying films. The sensitivity of the magnetoresistive effect film is lower in regions thereof near the bias-applying films due to an intensive bias magnetic field from the bias-applying films. However, the electrodes are disposed in an inner region having a high sensitivity avoiding those regions with a lower sensitivity to ensure a high sensitivity. The electrodes disposed on and under the magnetoresistive effect film are pillar-shaped to concentrate the sense current such that the sense current can be concentrically supplied exclusively to the region with the high sensitivity.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: June 29, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomomi Tunayama, Masayuki Takagishi, Kohichi Tateyama, Yuichi Ohsawa, Susumu Hashimoto, Michiko Hara, Akio Hori
  • Patent number: 6757142
    Abstract: A MR element with a magnetic sensing region and outside regions thereof which locate outside the magnetic sensing region along a track width direction, includes a multi-layered structure with an anti-ferromagnetic thin-film layer, a first ferromagnetic thin-film layer constituted by a single layer of ferromagnetic material or by multi layers of ferromagnetic material, a non-magnetic metal thin-film layer and a second ferromagnetic thin-film layer constituted by a single layer of ferromagnetic material or by multi layers of ferromagnetic material which are sequentially formed on a substrate. The all layers in the multi-layered structure exist in the magnetic sensing region, and at least the anti-ferromagnetic thin-film layer with its initial thickness exists in the outside regions.
    Type: Grant
    Filed: July 8, 1999
    Date of Patent: June 29, 2004
    Assignee: TDK Corporation
    Inventor: Koichi Terunuma
  • Patent number: 6756135
    Abstract: A spin valve thin-film magnetic element has an improved rate of change in resistance (&Dgr;R/R) that can be used for a narrower magnetic track. The spin valve thin-film magnetic element has a laminate that include an antiferromagnetic layer, a pinned magnetic layer, a non-magnetic conductive layer, a free magnetic layer, a back layer, specular-reflection layers and a pair of electrode layers formed at the two sides of the laminate. Preferably the specular reflection layer includes an oxide, such as &agr;-Fe2O3 or NiO, or a half-metal Heusler alloy, such as NiMnSb or PtMnSb.
    Type: Grant
    Filed: June 12, 2001
    Date of Patent: June 29, 2004
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Kenji Honda, Yoshihiko Kakihara
  • Patent number: 6754053
    Abstract: A magnetoresistance effect film including a magnetically pinned layer, a non-magnetic intermediate layer and a magnetically free layer has sidewall layers covering at least side surfaces of the magnetically pinned layer and the non-magnetic intermediate layer. The sidewall layers are made of a high-resistance oxide, nitride, fluoride, boride, sulfide or carbide having a specular reflection effect against conduction electrons, thereby to prevent non-elastic scattering of electrons and missing of spin information on side surfaces of the magnetoresistance effect film.
    Type: Grant
    Filed: March 29, 2002
    Date of Patent: June 22, 2004
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Yoshikawa, Masashi Sahashi, Katsuhiko Koi, Hitoshi Iwasaki, Hiromi Yuasa, Hideaki Fukuzawa
  • Publication number: 20040105192
    Abstract: The possibility of shorting between a spin valve and its underlying magnetic shield layer can be largely eliminated by choosing the bottom spin valve structure. However, doing so causes the hard longitudinal bias that is standard for all such devices to degrade. The present invention overcomes this problem by inserting a thin NiCr, Ni, Fe, or Cr layer between the antiferromagnetic layer and the longitudinal bias layers. This provides a smoother surface for the bias layers to be deposited onto, thereby removing structural distortions to the longitudinal bias layer that would otherwise be present. A process for manufacturing the structure is also described.
    Type: Application
    Filed: November 21, 2003
    Publication date: June 3, 2004
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Chen-Jung Chien, Chyu-Jiuh Torng, Cherng-Chyi Han, Moris Dovek, Po-Kang Wang, Mao-Min Chen
  • Publication number: 20040105191
    Abstract: A spin valve device comprises a free layer, a spacer layer, a pinned layer, an antiferromagnetic layer, and a patterned underlayer that includes a magnetic material for providing trackwidth and longitudinal bias. The patterned underlayer can comprise a buffer layer, an antiferromagnetic layer and a ferromagnetic layer. Alternatively, the patterned underlayer can comprises a buffer layer, a chromium layer and a hard biasing, permanent magnetic layer which provides trackwidth and longitudinal bias. A lower conductor can be located on the underlayer.
    Type: Application
    Filed: July 10, 2003
    Publication date: June 3, 2004
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Tai Min, Po-Kang Wang, Moris Musa Dovek
  • Publication number: 20040100737
    Abstract: A magnetic recording head includes an upper shield layer, a lower shield layer, a magnetoresistive film interposed between the upper shield layer and the lower shield layer, and a pair of leads electrically coupled to the magnetoresistive film, in which a pair of side shield layers constituted by portions of the upper shield layer is formed on both sides of the magnetoresistive film, and a spacing between each side shield layer and the magnetoresistive film is formed to be narrower than twice of a spacing between the upper shield layer and the lower shield layer, thereby a side reading amount can be made smaller than a conventional side reading value determined from the spacing between the upper and lower shield layers and a magnetic spacing between the head and a medium.
    Type: Application
    Filed: June 4, 2003
    Publication date: May 27, 2004
    Applicant: Hitachi, Ltd.
    Inventors: Kazuhiro Nakamoto, Hiroyuki Hoshiya, Chiaki Ishikawa
  • Publication number: 20040095691
    Abstract: An antiferromagnetic stabilization scheme is employed in a magnetic head for magnetically stabilizing a free layer of a spin valve. This is accomplished by utilizing an antiferromagnetic oxide film below a spin valve sensor in a read region and first and second lead layers in end regions and a ferromagnetic film in each of the lead layers that exchange couples to the antiferromagnetic oxide film in the end regions. The ferromagnetic films are pinned with their magnetic moments oriented parallel to an air bearing surface (ABS) of the magnetic head. The ferromagnetic film magnetostatically couples to the free layer which causes the free layer to be in a single magnetic domain state. Accordingly, when the free layer is subjected to magnetic incursions from a rotating disk in a disk drive, the free layer maintains a stable magnetic condition so that resistance changes of the free layer are not altered by differing magnetic conditions of the free layer.
    Type: Application
    Filed: November 7, 2003
    Publication date: May 20, 2004
    Inventors: Tsann Lin, Daniele Mauri
  • Publication number: 20040095690
    Abstract: Magnetic tunnel junction (MTJ) and charge perpendicular-to-plane (CPP) magnetic sensors are disclosed which have a first antiferromagnetic layer for pinning the magnetization direction in a pinned layer and a second antiferromagnetic layer for providing bias stabilization of a free layer. The two antiferromagnetic layers may be formed from the same material and using a spin-flop effect may be initialized simulataneously. A disk drive using these sensors is disclosed.
    Type: Application
    Filed: October 24, 2003
    Publication date: May 20, 2004
    Inventor: Robert S. Beach
  • Patent number: 6735060
    Abstract: A cap layer structure is provided with a first layer composed of a metal and a second cap layer composed of a metal oxide. The first cap layer reflects conduction electrons back into the mean free path of conduction electrons and the second cap layer protects the first cap layer from subsequent processing steps without degrading the performance of the first cap layer.
    Type: Grant
    Filed: June 20, 2001
    Date of Patent: May 11, 2004
    Assignee: International Business Machines Corporation
    Inventor: Hardayal Singh Gill
  • Patent number: 6735056
    Abstract: An electron device includes a first layer formed of a metal or metal alloy and a second layer adjoining the first layer and formed of a metal or metal alloy different from that of the first layer. In the region adjacent the first layer and the second layer, there is provided a concentration gradient layer formed of a mixture containing a metal or metal alloy contained in the first layer and a metal or metal alloy contained in the second layer. A covering film covers end faces of the first and second layers. With this arrangement, when a cleaning as by etching is carried out on the end faces of the multilayered film structure of the electron device, the end faces are etched in relatively smoothly connected surfaces because of the etched end face of the concentration gradient layer in a gentle slope, so that coverage of the covering film on the end faces of the multilayered film structure can be improved to increase the adherence strength of the covering film.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: May 11, 2004
    Assignee: TDK Corporation
    Inventors: Katsuaki Yanagiuchi, Wakako Shiramura