Patents by Inventor Kenji Iijima
Kenji Iijima 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: 6771473Abstract: The present invention provides a magnetoresistive element that includes a pair of magnetic layers and an intermediate layer between the magnetic layers. The intermediate layer contains at least three elements selected from Groups 2 to 17, and the elements include at least one selected from the group consisting of F, O, N, C and B. According to the invention, a magnetoresistive element with high magnetoresistance change ratio and low resistance can be provided. The invention also provides a method for producing a magnetoresistive element. The method includes forming a precursor and forming at least one part of the intermediate layer from the precursor. The precursor is reacted with at least one reactive species selected from the group consisting of oxygen atoms, nitrogen atoms and carbon atoms in a reactive atmosphere containing the reactive species.Type: GrantFiled: January 18, 2002Date of Patent: August 3, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masayoshi Hiramoto, Akihiro Odagawa, Nozomu Matukawa, Kenji Iijima, Hiroshi Sakakima
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Patent number: 6767655Abstract: 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: GrantFiled: August 16, 2001Date of Patent: July 27, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masayoshi Hiramoto, Nozomu Matukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
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Patent number: 6762142Abstract: A dielectric ceramic is made of a sintered body of a complex oxide including at least one element selected from the group consisting of Zr, Ti and Mn, at least one element selected from the group consisting of Mg, Zn and Co, and at least one element selected from the group consisting of Nb and Ta, wherein, the complex oxide is represented by a formula xZrO2-yTiO2-zA(1+w)/3B(2−w)/3O2 where ‘A’ in the formula denotes at least one element selected from the group (A) consisting of Mg, Zn and Co, ‘B’ denotes at one element selected from the group (B) consisting of Nb and Ta; x, y, z and w denote values in the respective ranges of 0.20≦x≦0.55, 0.40≦y≦0.55, 0.05≦z≦0.25, and 0≦w≦0.30, and x, y and z have a relationship represented as x+y+z=1; MnO is present in a range of 0.1 mol % to 1.Type: GrantFiled: September 19, 2002Date of Patent: July 13, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kojiro Okuyama, Junichi Kato, Hiroshi Kagata, Kenji Iijima
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Publication number: 20040096692Abstract: After an underlying layer, made of a single crystal metal material, has been formed on a semiconductor layer, part or all of the underlying layer is changed into a metal oxide layer by supplying oxygen thereto from above the underlying layer. Then, a ferroelectric or high-dielectric-constant film is further formed on the metal oxide layer. Since the film made of a metal material is formed on the semiconductor layer, a silicon dioxide film or the like is not formed easily. Thus, a dielectric film, which includes an underlying layer with a high dielectric constant and has a large capacitance per unit area, can be obtained. Various defects such as interface states in the semiconductor layer can also be reduced advantageously if these process steps are performed after a thermal oxide film has been formed on the semiconductor layer.Type: ApplicationFiled: November 7, 2003Publication date: May 20, 2004Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Takashi Nishikawa, Kenji Iijima
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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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Patent number: 6717780Abstract: A magneto-resistive element includes a vertical current type magneto-resistive element; a first conductor for causing a current to flow into the vertical current type magneto-resistive element; and a second conductor for causing the current to flow out of the vertical current type magneto-resistive element. The first conductor generates a first magnetic field based on the current. The second conductor generates a second magnetic field based on the current. The first conductor and the second conductor are located so that the first magnetic field and the second magnetic field act as a bias magnetic field applied on the vertical current type magneto-resistive element.Type: GrantFiled: October 2, 2001Date of Patent: April 6, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
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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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Patent number: 6639765Abstract: A magnetoresistive element with an improved magnetoresistive effect achieved by interposing a titanium nitride layer between a substrate and a spinel-type magnetic substance is provided. The magnetoresistive element comprises a substrate and a multilayer film formed on the substrate, and the multilayer film includes a first magnetic layer, a nonmagnetic layer formed on the first magnetic layer and a second magnetic layer formed on this nonmagnetic layer. An electric current is supplied in a direction perpendicular to a film surface of the multilayer film, and a change in electrical resistance is detected by the electric current based on a change in a relative angle between a magnetization direction of the first magnetic layer and a magnetization direction of the second magnetic layer. The first magnetic layer has a spinel crystal structure, and the multilayer film further includes a titanium nitride layer interposed between the substrate and the first magnetic layer.Type: GrantFiled: September 25, 2001Date of Patent: October 28, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideaki Adachi, Masayoshi Hiramoto, Kenji Iijima, Hiroshi Sakakima
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Publication number: 20030193758Abstract: A magneto-resistive element includes a magnetic substrate; a magnetic layer; and a non-magnetic layer provided between the magnetic substrate and the magnetic layer.Type: ApplicationFiled: May 20, 2003Publication date: October 16, 2003Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Hideaki Adachi, Kenji Iijima, Hiroshi Sakakima, Yasunari Sugita
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Publication number: 20030179071Abstract: The present invention provides a tunnel magnetoresistive (TMR) element that increases a MR ratio and suppresses the unevenness in resistance. In an embodiment of the present invention, a surface property-controlling layer is arranged between the substrate and the tunnel layer. In another embodiment, at least one of the magnetic layers sandwiching the tunnel layer has an oriented crystal plane other than the closest packed plane. In still another embodiment, the at least one of the magnetic layers includes a magnetic element and a non-magnetic element and has an average electron number of 23.5 to 25.5 or 26.5 to 36. In still another embodiment, the TMR element includes an excess-element capturing layer. This layer includes an alloy or a compound that contains the excess element. The content of the excess element in the capturing layer is higher than those in the magnetic layers.Type: ApplicationFiled: February 7, 2003Publication date: September 25, 2003Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
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Publication number: 20030116891Abstract: A dielectric ceramic is made of a sintered body of a complex oxide including at least one element selected from the group consisting of Zr, Ti and Mn, at least one element selected from the group consisting of Mg, Zn and Co, and at least one element selected from the group consisting of Nb and Ta, wherein, the complex oxide is represented by a formula xZrO2-yTiO2-zA(1+w)/3B(2−w)/3O2 where ‘A’ in the formula denotes at least one element selected from the group (A) consisting of Mg, Zn and Co, ‘B’ denotes at one element selected from the group (B) consisting of Nb and Ta; x, y, z and w denote values in the respective ranges of 0.20≦x≦0.55, 0.40≦y≦0.55, 0.05≦z≦0.25, and 0≦w≦0.30, and x, y and z have a relationship represented as x+y+z=1; MnO is present in a range of 0.1 mol % to 1.Type: ApplicationFiled: September 19, 2002Publication date: June 26, 2003Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Kojiro Okuyama, Junichi Kato, Hiroshi Kagata, Kenji Iijima
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Patent number: 6569240Abstract: After an underlying layer, made of a single crystal metal material, has been formed on a semiconductor layer, part or all of the underlying layer is changed into a metal oxide layer by supplying oxygen thereto from above the underlying layer. Then, a ferroelectric or high-dielectric-constant film is further formed on the metal oxide layer. Since the film made of a metal material is formed on the semiconductor layer, a silicon dioxide film or the like is not formed easily. Thus, a dielectric film, which includes an underlying layer with a high dielectric constant and has a large capacitance per unit area, can be obtained. Various defects such as interface states in the semiconductor layer can also be reduced advantageously if these process steps are performed after a thermal oxide film has been formed on the semiconductor layer.Type: GrantFiled: March 17, 2000Date of Patent: May 27, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takashi Nishikawa, Kenji Iijima
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Publication number: 20020191355Abstract: The present invention provides a magnetoresistive element that includes a pair of magnetic layers and an intermediate layer between the magnetic layers. The intermediate layer contains at least three elements selected from Groups 2 to 17, and the elements include at least one selected from the group consisting of F, O, N, C and B. According to the invention, a magnetoresistive element with high magnetoresistance change ratio and low resistance can be provided. The invention also provides a method for producing a magnetoresistive element. The method includes forming a precursor and forming at least one part of the intermediate layer from the precursor. The precursor is reacted with at least one reactive species selected from the group consisting of oxygen atoms, nitrogen atoms and carbon atoms in a reactive atmosphere containing the reactive species.Type: ApplicationFiled: January 18, 2002Publication date: December 19, 2002Applicant: Matsushita Electric Industrial Co., LtdInventors: Masayoshi Hiramoto, Akihiro Odagawa, Nozomu Matukawa, Kenji Iijima, Hiroshi Sakakima
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Publication number: 20020177013Abstract: 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: September 6, 2001Publication date: November 28, 2002Inventors: Masayoshi Hiramoto, Hiroshi Sakakima, Hideaki Adachi, Nozomu Matukawa, Kenji Iijima, Mitsuo Satomi
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Publication number: 20020096105Abstract: After an underlying layer, made of a single crystal metal material, has been formed on a semiconductor layer, part or all of the underlying layer is changed into a metal oxide layer by supplying oxygen thereto from above the underlying layer. Then, a ferroelectric or high-dielectric-constant film is further formed on the metal oxide layer. Since the film made of a metal material is formed on the semiconductor layer, a silicon dioxide film or the like is not formed easily. Thus, a dielectric film, which includes an underlying layer with a high dielectric constant and has a large capacitance per unit area, can be obtained. Various defects such as interface states in the semiconductor layer can also be reduced advantageously if these process steps are performed after a thermal oxide film has been formed on the semiconductor layer.Type: ApplicationFiled: March 28, 2002Publication date: July 25, 2002Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Takashi Nishikawa, Kenji Iijima
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Publication number: 20020067581Abstract: A magneto-resistive element includes a vertical current type magneto-resistive element; a first conductor for causing a current to flow into the vertical current type magneto-resistive element; and a second conductor for causing the current to flow out of the vertical current type magneto-resistive element. The first conductor generates a first magnetic field based on the current. The second conductor generates a second magnetic field based on the current. The first conductor and the second conductor are located so that the first magnetic field and the second magnetic field act as a bias magnetic field applied on the vertical current type magneto-resistive element.Type: ApplicationFiled: October 2, 2001Publication date: June 6, 2002Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
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Publication number: 20020055016Abstract: 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: ApplicationFiled: August 16, 2001Publication date: May 9, 2002Inventors: Masayoshi Hiramoto, Nozomu Matukawa, Akihiro Odagawa, Kenji Iijima, Hiroshi Sakakima
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Publication number: 20020045070Abstract: 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: ApplicationFiled: June 4, 2001Publication date: April 18, 2002Inventors: Hiroshi Sakakima, Hideaki Adachi, Mitsuo Satomi, Yasuhiro Kawawake, Yasunari Sugita, Kenji Iijima
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Publication number: 20020044391Abstract: A magneto-resistive element includes a magnetic substrate; a magnetic layer; and a non-magnetic layer provided between the magnetic substrate and the magnetic layer.Type: ApplicationFiled: November 8, 2001Publication date: April 18, 2002Inventors: Masayoshi Hiramoto, Nozomu Matsukawa, Akihiro Odagawa, Hideaki Adachi, Kenji Iijima, Hiroshi Sakakima