Patents by Inventor Mitsuo Satomi
Mitsuo Satomi 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).
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Patent number: 7079361Abstract: The present invention provides a magnetoresistive (MR) element that is excellent in MR ratio and thermal stability and includes at least one magnetic layer including a ferromagnetic material M-X expressed by M100-aXa. Here, M is at least one selected from Fe, Co and Ni, X is expressed by X1bX2cX3d (X1 is at least one selected from Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt and Au, X2 is at least one selected from Al, Sc, Ti, V, Cr, Mn, Ga, Ge, Y, Zr, Nb, Mo, Hf, Ta, W, Re, Zn and lanthanide series elements, and X3 is at least one selected from Si, B, C, N, O, P and S), and a, b, c and d satisfy 0.05?a?60, 0?b?60, 0?c?30, 0?d?20, and a=b+c+d.Type: GrantFiled: February 16, 2005Date of Patent: July 18, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yasunari Sugita, Masayoshi Hiramoto, Nozomu Matsukawa, Mitsuo Satomi, Yoshio Kawashima, Akihiro Odagawa
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Patent number: 6954372Abstract: A magnetic memory device that includes a magnetoresistive element, a conductive wire for generating magnetic flux that changes a resistance value of the magnetoresistive element, and at least one ferromagnetic member through which the magnetic flux passes. The ferromagnetic member forms a magnetic gap at a position where the magnetic flux passes through the magnetoresistive element. A length of the magnetoresistive element that is measured in a direction parallel to the magnetic gap is less than or equal to twice the length of the magnetic gap. A length of a path traced by the magnetic flux in the ferromagnetic member is less than or equal to 1.0 ?m. The length of the path is also greater than or equal to five times the thickness of the ferromagnetic member and/or is greater than or equal to a length of the ferromagnetic member in the direction of the drawing of the conductive wire divided by five.Type: GrantFiled: January 18, 2002Date of Patent: October 11, 2005Assignee: Matsushita Electric Co., Ltd.Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita
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Patent number: 6950333Abstract: A magnetic memory of the present invention includes two or more memory layers and two or more tunnel layers that are stacked in the thickness direction of the layers. The two or more memory layers are connected electrically in series. A group of first layers includes at least one layer selected from the two or more memory layers. A group of second layers includes at least one layer selected from the two or more memory layers. A resistance change caused by magnetization reversal in the group of first layers differs from a resistance change caused by magnetization reversal in the group of second layers.Type: GrantFiled: October 24, 2003Date of Patent: September 27, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita, Yoshio Kawashima
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Patent number: 6917492Abstract: A magnetoresistive element includes a pair of ferromagnetic layers and a non-magnetic layer arranged between the ferromagnetic layers. At least one of the ferromagnetic layers has a composition expressed by (MxLy)100-zRz at the interface with the non-magnetic layer. The non-magnetic layer includes at least one element selected from the group consisting of B, C, N, O, and P. Here, M is FeaCobNic, L is at least one element selected from the group consisting of Pt, Pd, Ir, and Rh, R is an element that has a lower free energy to form a compound with the element of the non-magnetic layer that is at least one selected from the group consisting of B, C, N, O, and P than does any other element included in the composition as M or L, and a, b, c, x, y, and z satisfy a+b+c=100, a?30, x+y=100, 0<y?35, and 0.1?z?20. This element can provide a high MR ratio. A method for manufacturing a magnetoresistive element includes a first heat treatment process at 200° C. to 330° C.Type: GrantFiled: June 27, 2003Date of Patent: July 12, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima
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Publication number: 20050135020Abstract: The present invention provides a magnetoresistive (MR) element that is excellent in MR ratio and thermal stability and includes at least one magnetic layer including a ferromagnetic material M-X expressed by M100-aXa. Here, M is at least one selected from Fe, Co and Ni, X is expressed by X1bX2c,X3d (X1 is at least one selected from Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt and Au, X2 is at least one selected from Al, Sc, Ti, V, Cr, Mn, Ga, Ge, Y, Zr, Nb, Mo, Hf, Ta, W, Re, Zn and lanthanide series elements, and X3 is at least one selected from Si, B, C, N, O, P and S), and a, b, c and d satisfy 0.05?a?60, 0?b?60, 0?c?30, 0?d?20, and a=b+c+d.Type: ApplicationFiled: February 16, 2005Publication date: June 23, 2005Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Yasunari Sugita, Masayoshi Hiramoto, Nozomu Matsukawa, Mitsuo Satomi, Yoshio Kawashima, Akihiro Odagawa
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Publication number: 20050111147Abstract: A magnetoresistive element includes a pair of magnetic layers sandwiching an intermediate layer, at least one of the magnetic layers includes an oxide ferrite having a plane orientation with a (100), (110) or (111) plane. The oxide can be formed by sputtering with an oxide target while applying a bias voltage to a substrate including a plane on which the oxide ferrite is to be formed so as to adjust the amount of oxygen supplied to the oxide ferrite from the target. One of the magnetic layers is a pinned magnetic layer, and the pinned magnetic layer includes at least one non-magnetic film and magnetic films sandwiching the non-magnetic film. The magnetic films can be coupled with one another by magnetostatic coupling or antiferromagnetic coupling, generating negative magnetic coupling. Magnetic shifts are reduced by generating negative coupling. This element also has an improved thermal resistance.Type: ApplicationFiled: December 28, 2004Publication date: May 26, 2005Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Masayoshi Hiramoto, Hiroshi Sakakima, Hideaki Adachi, Nozomu Matukawa, Kenji Iijima, Mitsuo Satomi
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Patent number: 6878979Abstract: A spin switch that can be driven with voltage. This spin switch includes the following: a ferromagnetic material; a magnetic semiconductor magnetically coupled to the ferromagnetic material; an antiferromagnetic material magnetically coupled to the magnetic semiconductor; and an electrode connected to the magnetic semiconductor via an insulator. A change in the electric potential of the electrode causes the magnetic semiconductor to make a reversible transition between a ferromagnetic state and a paramagnetic state. When the magnetic semiconductor is changed to the ferromagnetic state, the ferromagnetic material is magnetized in a predetermined direction due to the magnetic coupling with the magnetic semiconductor.Type: GrantFiled: January 18, 2002Date of Patent: April 12, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita
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Patent number: 6861940Abstract: A magnetoresistive element of the present invention includes a multilayer structure that includes a non-magnetic layer (3) and a pair of ferromagnetic layers (1, 2) stacked on both sides of the non-magnetic layer (3). A resistance value differs depending on a relative angle between the magnetization directions of the ferromagnetic layers (1, 2) at the interfaces with the non-magnetic layer (3). The composition of at least one of the ferromagnetic layers (1, 2) in a range of 2 nm from the interface with the non-magnetic layer (3) is expressed by (MxOy)1-zZz, where Z is at least one element selected from the group consisting of Ru, Os, Rh, Ir, Pd, Pt, Cu, Ag, and Au, M is at least one element selected from the group consisting of elements other than Z and O and includes a ferromagnetic metal, and x, y, and z satisfy 0.33<y/x<1.33, 0<x, 0<y, and 0?z?0.4. This magnetoresistive element can have excellent heat resistance and magnetoresistance characteristics.Type: GrantFiled: December 10, 2003Date of Patent: March 1, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Nozomu Matsukawa, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima
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Publication number: 20040130431Abstract: A magnetoresistive element of the present invention includes a multilayer structure that includes a non-magnetic layer (3) and a pair of ferromagnetic layers (1, 2) stacked on both sides of the non-magnetic layer (3). A resistance value differs depending on a relative angle between the magnetization directions of the ferromagnetic layers (1, 2) at the interfaces with the non-magnetic layer (3). The composition of at least one of the ferromagnetic layers (1, 2) in a range of 2 nm from the interface with the non-magnetic layer (3) is expressed by (MxOy)1-zZz, where Z is at least one element selected from the group consisting of Ru, Os, Rh, Ir, Pd, Pt, Cu, Ag, and Au, M is at least one element selected from the group consisting of elements other than Z and O and includes a ferromagnetic metal, and x, y, and z satisfy 0.33<y/x<1.33, 0<x, 0<y, and 0≦z≦0.4. This magnetoresistive element can have excellent heat resistance and magnetoresistance characteristics.Type: ApplicationFiled: December 10, 2003Publication date: July 8, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Nozomu Matsukawa, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima
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Publication number: 20040085807Abstract: A magnetic memory of the present invention includes two or more memory layers and two or more tunnel layers that are stacked in the thickness direction of the layers. The two or more memory layers are connected electrically in series. A group of first layers includes at least one layer selected from the two or more memory layers. A group of second layers includes at least one layer selected from the two or more memory layers. A resistance change caused by magnetization reversal in the group of first layers differs from a resistance change caused by magnetization reversal in the group of second layers.Type: ApplicationFiled: October 24, 2003Publication date: May 6, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita, Yoshio Kawashima
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Publication number: 20040086752Abstract: The present invention provides a magnetoresistive element that has excellent magnetoresistance characteristics over a conventional magnetoresistive element. The magnetoresistive element is produced by a method including heat treatment at 330° C. or more and characterized in that the longest distance from a centerline of a non-magnetic layer to the interfaces between a pair of ferromagnetic layers and the non-magnetic layer is not more than 10 nm. This element can be produced, e.g., by forming an underlying film on a substrate, heat-treating the underlying film at 400° C. or more, decreasing surface roughness by irradiating the surface of the underlying film with an ion beam, and forming the ferromagnetic layers and the non-magnetic layer. The longest distance is reduced relatively even when M1 (at least one element selected from Tc, Re, Ru, Os, Rh, Ir, Pd, Pt, Cu, Ag and Au) is added to the ferromagnetic layers in the range of 2 nm from the interfaces with the non-magnetic layer.Type: ApplicationFiled: October 24, 2003Publication date: May 6, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO.Inventors: Nozomu Matsukawa, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima, Masayoshi Hiramoto
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Publication number: 20040080874Abstract: The invention provides a magnetoresistive element in which the pinned magnetic layer includes at least one non-magnetic film and magnetic films sandwiching that non-magneticfilm, and the magnetic films are coupled with one another by magnetostatic coupling via the non-magnetic film. This element has an improved thermal resistance. Furthermore, the invention provides a magnetoresistive element in which the pinned magnetic layer is as described above. The magnetic films can be coupled with one another by magnetostatic coupling or antiferromagnetic coupling generating negative magnetic coupling. In this element, the magnetic field shift is reduced. Furthermore, the invention provides a magnetoresistive element in which at least one of the magnetic layers sandwiching the intermediate layer includes an oxide ferrite having a plane orientation with a (100), (110) or (111) plane. A magnetic field is introduced in a direction of the axis of easy magnetization in the plane.Type: ApplicationFiled: October 16, 2003Publication date: April 29, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Masayoshi Hiramoto, Hiroshi Sakakima, Hideaki Adachi, Nozomu Matukawa, Kenji Iijima, Mitsuo Satomi
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Publication number: 20040057295Abstract: The present invention provides a magnetic memory device that includes the following: a magnetoresistive element; a conductive wire for generating magnetic flux that changes a resistance value of the magnetoresistive element; and at least one ferromagnetic member through which the magnetic flux passes. The at least one ferromagnetic member forms a magnetic gap at a position where the magnetic flux passes through the magnetoresistive element. The following relationships are established: a) Ml≦2Lg; b) at least one selected from Lw/Ly≦5 and Ly/Lt≧5; and c) Ly≦1.0 &mgr;m, where Ml is a length of the magnetoresistive element that is measured in a direction parallel to the magnetic gap, Lg is a length of the magnetic gap, Lt is a thickness of the ferromagnetic member, Lw is a length of the ferromagnetic member in the direction of drawing of the conductive wire, and Ly is a length of a path traced by the magnetic flux in the ferromagnetic member.Type: ApplicationFiled: July 8, 2003Publication date: March 25, 2004Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita
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Publication number: 20040027733Abstract: A magnetoresistive element includes a pair of ferromagnetic layers and a non-magnetic layer arranged between the ferromagnetic layers. At least one of the ferromagnetic layers has a composition expressed by (MxLy)100−zRz at the interface with the non-magnetic layer. The non-magnetic layer includes at least one element selected from the group consisting of B, C, N, O, and P. Here, M is FeaCobNic, L is at least one element selected from the group consisting of Pt, Pd, Ir, and Rh, R is an element that has a lower free energy to form a compound with the element of the non-magnetic layer that is at least one selected from the group consisting of B, C, N, O, and P than does any other element included in the composition as M or L, and a, b, c, x, y, and z satisfy a+b+c=100, a≧30, x+y=100, 0<y≦35, and 0.1≦z≦20. This element can provide a high MR ratio. A method for manufacturing a magnetoresistive element includes a first heat treatment process at 200° C.Type: ApplicationFiled: June 27, 2003Publication date: February 12, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Yasunari Sugita, Mitsuo Satomi, Yoshio Kawashima
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Patent number: 6686071Abstract: A magnetic recording medium includes a magnetic film for signal recording and a film containing M2Oy as a main component that is magnetically exchange-coupled to the magnetic film to increase the effective V and Ku of the magnetic film and to suppress thermal fluctuation. Herein, M is at least one element selected from Fe, Co, Ni, alkaline earth elements, Y, lanthanoids and Bi and includes at least one selected from Fe, Co and Ni as an essential element, and y is a value satisfying 2.8<y<3.2.Type: GrantFiled: June 4, 2001Date of Patent: February 3, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Sakakima, Hideaki Adachi, Mitsuo Satomi, Yasuhiro Kawawake, Yasunari Sugita, Kenji Iijima
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Patent number: 6680831Abstract: The invention provides a magnetoresistive element in which the pinned magnetic layer includes at least one non-magnetic film and magnetic films sandwiching that non-magnetic film, and the magnetic films are coupled with one another by magnetostatic coupling via the non-magnetic film. This element has an improved thermal resistance. Furthermore, the invention provides a magnetoresistive element in which the pinned magnetic layer is as described above. The magnetic films can be coupled with one another by magnetostatic coupling or antiferromagnetic coupling generating negative magnetic coupling. In this element, the magnetic field shift is reduced. Furthermore, the invention provides a magnetoresistive element in which at least one of the magnetic layers sandwiching the intermediate layer includes an oxide ferrite having a plane orientation with a (100), (110) or (111) plane. A magnetic field is introduced in a direction of the axis of easy magnetization in the plane.Type: GrantFiled: September 6, 2001Date of Patent: January 20, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masayoshi Hiramoto, Hiroshi Sakakima, Hideaki Adachi, Nozomu Matukawa, Kenji Iijima, Mitsuo Satomi
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Publication number: 20030197505Abstract: A magnetoresistance effect element includes a free layer, in which a magnetization direction thereof is easily rotated in response to an external magnetic field, a first non-magnetic layer, and a first pinned layer provided on a side opposite to the free layer of the first non-magnetic layer, in which a magnetization direction of the first pinned layer is not easily rotated in response to the external magnetic field. At least one of the first pinned layer and the free layer includes a first metal magnetic film contacting the first non-magnetic layer, and a first oxide magnetic film.Type: ApplicationFiled: March 21, 2003Publication date: October 23, 2003Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Sakakima, Yasunari Sugita, Mitsuo Satomi, Yasuhiro Kawawake, Masayoshi Hiramoto, Nozomu Matsukawa
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Publication number: 20030184921Abstract: The present invention provides a magnetoresistive (MR) element that is excellent in MR ratio and thermal stability and includes at least one magnetic layer including a ferromagnetic material M—X expressed by M100−aXa. Here, M is at least one selected from Fe, Co and Ni, X is expressed by X1bX2cX3d (X1 is at least one selected from Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt and Au, X2 is at least one selected from Al, Sc, Ti, V, Cr, Mn, Ga, Ge, Y, Zr, Nb, Mo, Hf, Ta, W, Re, Zn and lanthanide series elements, and X3 is at least one selected from Si, B, C, N, O, P and S), and a, b, c and d satisfy 0.05≦a≦60, 0≦b≦60, 0≦c≦30, 0≦d≦20, and a=b+c+d.Type: ApplicationFiled: February 19, 2003Publication date: October 2, 2003Inventors: Yasunari Sugita, Masayoshi Hiramoto, Nozomu Matsukawa, Mitsuo Satomi, Yoshio Kawashima, Akihiro Odagawa
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Publication number: 20030156360Abstract: A magnetoresistance effect device of the present invention includes a multilayer film. The multilayer film includes an antiferromagnetic film, a first ferromagnetic film, a non-magnetic film and a second ferromagnetic film, which are provided in this order on a non-magnetic substrate directly or via an underlying layer. The antiferromagnetic film comprises an &agr;-Fe2O3 film. A surface roughness of the multilayer film is about 0.5 nm or less.Type: ApplicationFiled: March 11, 2003Publication date: August 21, 2003Inventors: Yasuhiro Kawawake, Mitsuo Satomi, Yasunari Sugita, Hiroshi Sakakima
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Publication number: 20030142539Abstract: The present invention provides a spin switch that can be driven with voltage. This spin switch includes the following: a ferromagnetic material; a magnetic semiconductor magnetically coupled to the ferromagnetic material; an antiferromagnetic material magnetically coupled to the magnetic semiconductor; and an electrode connected to the magnetic semiconductor via an insulator. A change in the electric potential of the electrode causes the magnetic semiconductor to make a reversible transition between a ferromagnetic state and a paramagnetic state. When the magnetic semiconductor is changed to the ferromagnetic state, the ferromagnetic material is magnetized in a predetermined direction due to the magnetic coupling with the magnetic semiconductor.Type: ApplicationFiled: October 18, 2002Publication date: July 31, 2003Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita