Patents by Inventor Naoya Hasegawa

Naoya Hasegawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Exchange coupling film and magnetoresistive element using the same
    Patent number: 7119996
    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: July 9, 2001
    Date of Patent: October 10, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Exchange coupling film and magnetoresistive element using the same
    Patent number: 7119998
    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: August 17, 2005
    Date of Patent: October 10, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Magnetic sensing element containing quaternary Heusler alloy Co2Mn (Ge1-xSnx) which constitutes a free magnetic layer or pinned magnetic layer
    Publication number: 20060215330
    Abstract: A magnetic sensing element is described, including a multilayer film including a pinned magnetic layer, a free magnetic layer disposed on the pinned magnetic layer with a nonmagnetic layer therebetween, wherein a current flows perpendicular to the surfaces of the individual layers of the multilayer film. The nonmagnetic layer is composed of Cu and has a face-centered cubic lattice crystal structure in which the {111} planes are preferentially oriented in a direction parallel to the surfaces of the layer. At least one of the pinned magnetic layer and the free magnetic layer includes a Co2Mn(Ge1-xSnx) alloy layer, the subscript x satisfying the range of 0.2?x?0.8; and the Co2Mn(Ge1-xSnx) alloy layer has a body-centered cubic lattice crystal structure in which the {110} planes are preferentially oriented in a direction parallel to the surfaces of the layer.
    Type: Application
    Filed: March 22, 2006
    Publication date: September 28, 2006
    Inventors: Yosuke Ide, Masamichi Saito, Masahiko Ishizone, Naoya Hasegawa
  • Angle sensor having low waveform distortion
    Publication number: 20060214656
    Abstract: A magnetoresistive element includes a meandering X-axis array that is constituted by X-axis segments alternately connected, and a meandering Y-axis array that is constituted by Y-axis segments alternately connected. When rotated 90°, the Y-axis array has the same layout as the X-axis array. Such a structure cancels the electrical resistance change due to the AMR effect, thus reducing the waveform distortion of output voltage.
    Type: Application
    Filed: May 31, 2006
    Publication date: September 28, 2006
    Inventors: Yoshihiro Sudo, Ichiro Tokunaga, Yoshikazu Shimizu, Naoya Hasegawa, Fumihito Koike
  • Exchange coupling film and magnetoresistive element using the same
    Publication number: 20060215331
    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: Application
    Filed: April 24, 2006
    Publication date: September 28, 2006
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Magnetic detective head comprising free layer
    Publication number: 20060203398
    Abstract: A free magnetic layer is a laminated body of a CO2MnZ alloy layer (Z is one or more elements selected from a group consisting of Al, Sn, In, Sb, Ga, Si, Ge, Pb, and Zn) and a CoaFe100-a alloy layer. The CoaFe100-a alloy layer has a composition ratio 76?a?100 or a face-centered cubic (fcc) structure, in which an equivalent crystal face expressed as a {111} plane is preferentially oriented in a direction parallel to a film surface, and the CoaFe100-a alloy layer is in contact with the nonmagnetic material layer.
    Type: Application
    Filed: March 10, 2006
    Publication date: September 14, 2006
    Inventors: Masahiko Ishizone, Masamichi Saito, Yosuke Ide, Naoya Hasegawa
  • Magnetic detecting device having free layer or pinned layer formed by lamination of magnetic alloy and Cu layer and method of manufacturing magnetic detecting device
    Publication number: 20060203396
    Abstract: A magnetic detecting device and a method of manufacturing the magnetic detecting device are provided. Non-magnetic material layer-side magnetic layers of second fixed magnetic layers form a fixed magnetic layer. Each of the non-magnetic material layer-side magnetic layers and a free magnetic layer is formed of a layer, for example, a CoMnGeCu layer. In the CoMnGeCu layer, a bulk scattering coefficient may become larger, as compared with a CoMnGe layer. As a result, it is possible to increase the product between a magnetoresistance variation and a device area. Further, the ferromagnetic coupling magnetic field can be decreased. The Cu is added by a range which is larger than 0 at. % and not more than 17.5 at. % (average composition ratio).
    Type: Application
    Filed: February 28, 2006
    Publication date: September 14, 2006
    Inventors: Yosuke Ide, Masamichi Saito, Masahiko Ishizone, Naoya Hasegawa, Kazumasa Nishimura
  • Magnetic sensor with second antiferromagnetic layer having smaller depth in height direction than free layer
    Patent number: 7106560
    Abstract: An end portion of a backfill gap layer is provided on two side portions of a free magnetic layer in a back region, and second antiferromagnetic layers are formed on the two side portions of the free magnetic layer from a face opposing a recording medium to the end portion of the backfill gap layer. Accordingly, in the free magnetic layer in the back region, a bias magnetic field in the magnetic layer is decreased as compared to that in the front region. Hence, a magnetic sensor can be manufactured which can improve the reproduction sensitivity of a central portion of the free magnetic layer to an external magnetic field as compared to that in the past without decreasing the exchange stiffness constant and which can suppress the generation of side reading.
    Type: Grant
    Filed: July 14, 2003
    Date of Patent: September 12, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Exchange coupling film and magnetoresistive element using the same
    Patent number: 7106559
    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: August 17, 2005
    Date of Patent: September 12, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Magnetic detecting element having free layer formed of NiFe alloy and method of manufacturing the same
    Publication number: 20060198060
    Abstract: There are provided a magnetic detecting element capable of maintaining large ?RA and of reducing magnetostriction by improving a material forming a free magnetic layer, and a method of manufacturing the same. An NiFeX alloy layer is formed in a free magnetic layer. For example, the element X is Cu. The NiFeX alloy layer formed in the free magnetic layer makes it possible to maintain large ?RA and to more reduce the magnetostriction of the free magnetic layer, compared with a structure in which an NiFe alloy layer is formed in the free magnetic layer.
    Type: Application
    Filed: February 21, 2006
    Publication date: September 7, 2006
    Inventors: Masahiko Ishizone, Yosuke Ide, Masamichi Saito, Naoya Hasegawa
  • Magnetic detectible head comprising free layer
    Publication number: 20060198061
    Abstract: There is provided a magnetic detecting element having a large ?RA. A free magnetic layer has a three layer structure in which a CoFe layer, an NiaFeb alloy layer (where a and b are represented by at %, 0?a?25, and a+b=100), and a CoFe layer are laminated from the bottom. If the at % of Ni in an NiFe alloy that exists in the free magnetic layer is in this range, a spin-dependent bulk scattering coefficient ? increases, and the product ?RA of the resistance variation of the magnetic detecting element and the area of the element can be made increased.
    Type: Application
    Filed: February 27, 2006
    Publication date: September 7, 2006
    Inventors: Yosuke Ide, Masamichi Saito, Masahiko Ishizone, Naoya Hasegawa
  • Magnetic sensor using NiFe alloy for pinned layer
    Publication number: 20060198058
    Abstract: A magnetic layer 14c of a pinned magnetic layer 14 has a three-layered structure formed of a CoFe layer 14c1, a NiaFeb alloy layer 14c2 (where a and b each indicate atomic percent, and 0<a?25 and a+b=100 are satisfied), and a CoFe layer 14c3 laminated in that order from the bottom. The content of Ni in the NiaFeb alloy layer 14c2 is set in the range of more than 0 to 25 atomic percent, which is smaller than that in the past. Accordingly, a product ?R·A can be increased as compared to that in the past, ?R being the change in resistance and A being an element area of a magnetic sensor.
    Type: Application
    Filed: February 28, 2006
    Publication date: September 7, 2006
    Inventors: Yosuke Ide, Masamichi Saito, Masahiko Ishizone, Naoya Hasegawa
  • CPP magnetic detectig device containing NiFe alloy on free layer thereof
    Publication number: 20060198062
    Abstract: A magnetic detecting device having a large ?RA value is provided. A free magnetic layer has a three layer structure in which a CoFe layer, a NiaFeb alloy layer (here, a and b are represented by at %, and satisfy the relationship of 47?a?77 and a+b=100), and a CoFe layer are laminated. In addition, pinned magnetic layers have heusler alloy layers, which are made of a heusler alloy such as a Co2MnGe alloy. Accordingly, the product ?RA of a magnetic resistance variation ?R of the magnetic detecting device and an area A of the device can have a value of 5 m??m2 or more.
    Type: Application
    Filed: February 28, 2006
    Publication date: September 7, 2006
    Inventors: Yosuke Ide, Masamichi Saito, Masahiko Ishizone, Naoya Hasegawa
  • Magnetic sensing element including free layer having gradient composition and method for manufacturing the same
    Publication number: 20060188750
    Abstract: A magnetic sensing element which allows a high reproduction output and reduction in asymmetry of reproduction waveform to become mutually compatible, as well as a method for manufacturing the same, is provided. In the inside of a second pinned magnetic layer and a free magnetic layer, the atomic percentage of an element Z is decreased in a region close to a non-magnetic material layer. Consequently, the ferromagnetic coupling magnetic field due to magnetostatic coupling (topological coupling) between the pinned magnetic layer and the free magnetic layer can be reduced. At the same time, in a region at a distance from the non-magnetic material layer, the atomic percentage of an element Z is increased, a spin-dependent bulk scattering coefficient is increased, and a product of the amount of change in magnetic resistance and the element area of the magnetic sensing element can be maintained at a high level.
    Type: Application
    Filed: February 13, 2006
    Publication date: August 24, 2006
    Inventors: Yosuke Ide, Masamichi Saito, Masahiko Ishizone, Naoya Hasegawa
  • Exchange coupled film having improved current-carrying reliability and improved rate of change in resistance and magnetic sensing element using same
    Patent number: 7092222
    Abstract: A seed layer having a chromium content in the range of 35 to 60 atomic percent and a thickness of 10 to 200 ? is deposited to have a single phase of the face-centered cubic structure by optimizing the sputtering conditions, etc. The surface of the seed layer maintaining the face-centered cubic structure exhibits improved wettability, and the rate of change in resistance ?R/R can thereby be improved.
    Type: Grant
    Filed: February 7, 2005
    Date of Patent: August 15, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Masamichi Saito
  • Magnetic head comprising magnetic domain control layer formed on ABS-side of magnetic flux guide for GMR element and method of manufacturing the magnetic head
    Patent number: 7092218
    Abstract: The present invention provides a magnetic head including a magnetic flux guide layer for effectively inducing an external magnetic field in a free magnetic layer. A magnetic domain control layer is formed in a space below the magnetic flux guide layer and in front of a multilayer film near a surface facing a recording medium. Therefore, the shape of the magnetic flux guide layer can be made substantially flat to improve flux transmission efficiency. Also, the magnetization of the magnetic flux guide layer is controlled by laminating the magnetic flux guide layer on the magnetic domain control layer. Therefore, the magnetic domain control layer can be formed in a substantially flat thin film to stabilize a bias magnetic field to be supplied to the magnetic flux guide layer. Furthermore, the gap length of the magnetic head can be kept short.
    Type: Grant
    Filed: June 17, 2003
    Date of Patent: August 15, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Giant magnetoresistive element
    Patent number: 7079362
    Abstract: A giant magnetoresistive (GMR) element includes a first antiferromagnetic layer, a pinned magnetic layer having a magnetization direction pinned by the first antiferromagnetic layer, a nonmagnetic material layer, a free magnetic layer having a magnetization direction with a central portion changing with an external magnetic field, a nonmagnetic layer, ferromagnetic layers formed on both sides of the nonmagnetic layer, and second antiferromagnetic layers for aligning the magnetization direction of the ferromagnetic layers perpendicular to that of the pinned magnetic layer. The magnetization directions of the free magnetic and ferromagnetic layers are antiparallel to each other. At least the free magnetic layer, the nonmagnetic layers and the ferromagnetic layers have continuous surfaces ? at both end surfaces in the track width direction.
    Type: Grant
    Filed: August 6, 2003
    Date of Patent: July 18, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventor: Naoya Hasegawa
  • Method of producing exchange coupling film and method of producing magnetoresistive sensor by using exchange coupling film
    Patent number: 7077936
    Abstract: A laminate structure includes an antiferromagnetic layer, a pinned magnetic layer, and a seed layer contacting the antiferromagnetic layer on a side opposite to pinned magnetic layer. The seed layer is constituted mainly by face-centered cubic crystals with (111) planes preferentially oriented. The seed layer is preferably non-magnetic. Layers including the antiferromagnetic layer, a free magnetic layer, and layers therebetween, have (111) planes preferentially oriented.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: July 18, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Naoya Hasegawa, Yosuke Ide, Kenichi Tanaka
  • Magnetic sensing element with free layer biasing using varying thickness nonmagnetic coupling layer
    Patent number: 7075759
    Abstract: A nonmagnetic layer comprising Ru formed on a free magnetic layer, wherein a ferromagnetic layer and a second antiferromagnetic layer are formed on each outer side of the nonmagnetic layer. A ferromagnetic coupling is effectively generated between the ferromagnetic layer and each outer side of the free magnetic layer. Magnetization of the free magnetic layer is adequately controlled by the ferromagnetic coupling without damaging each outer side of the free magnetic layer to allow manufacture of a magnetic sensing element capable of properly defining a narrow track width.
    Type: Grant
    Filed: September 20, 2002
    Date of Patent: July 11, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Naoya Hasegawa, Eiji Umetsu
  • Exchange coupling film, magnetic detecting element using the exchange coupling film, and method of making same
    Patent number: 7063904
    Abstract: Each of an antiferromagnetic layer and a pinned magnetic layer has a region containing a Cr element, thereby increasing an exchange coupling magnetic field (Hex) produced between the antiferromagnetic layer and the pinned magnetic layer. Therefore, the exchange coupling magnetic field produced between the antiferromagnetic layer and the pinned magnetic layer can be increased, and a coupling magnetic field due to RKKY interaction can also be increased, thereby increasing a one-directional exchange bias magnetic field (Hex*) in the pinned magnetic layer as compared with a conventional exchange coupling film.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: June 20, 2006
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kazuaki Ikarashi, Naoya Hasegawa