Patents by Inventor Katsuhiko Koui
Katsuhiko Koui 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).
-
Patent number: 7046489Abstract: There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, a resistance regulating layer is provided in at least one of a pinned layer, a free layer and an non-magnetic intermediate layer. The resistance regulating layer contains, as a principal component, an oxide, a nitride, a fluoride, a carbide or a boride. The resistance regulating layer may be a continuous film or may have pin holes. Thus, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.Type: GrantFiled: March 16, 2005Date of Patent: May 16, 2006Assignee: Kabushiki Kaisha ToshibaInventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
-
Publication number: 20060098353Abstract: A magnetoresistive element has a magnetization pinned layer a magnetization direction of which is substantially pinned in one direction, a magnetization free layer a magnetization direction of which varies depending on an external field, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating the insulating layer, the magnetization pinned layer or magnetization free layer located under the spacer layer comprising crystal grains separated by grain boundaries extending across a thickness thereof, in which, supposing that an in-plane position of one end of each of the crystal grains is set to 0 and an in-plane position of a grain boundary adjacent to the other end of the crystal grain is set to 100, the current path corresponding the crystal grain is formed on a region in a range between 20 and 80 of the in-plane position.Type: ApplicationFiled: November 9, 2005Publication date: May 11, 2006Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hideaki Fukuzawa, Hiromi Yuasa, Katsuhiko Koui, Hitoshi Iwasaki
-
Patent number: 7038893Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.Type: GrantFiled: January 31, 2005Date of Patent: May 2, 2006Assignee: Kabushiki Kaisha ToshibaInventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
-
Publication number: 20060071287Abstract: In a spin valve type element, an interface insertion layer (32, 34) of a material exhibiting large spin-dependent interface scattering is inserted in a location of a magnetically pinned layer (16) or a magnetically free layer (20) closer to a nonmagnetic intermediate layer (18). A nonmagnetic back layer (36) may be additionally inserted as an interface not in contact with the nonmagnetic intermediate layer to increase the output by making use of spin-dependent interface scattering along the interface between the pinned layer and the nonmagnetic back layer or between the free layer and the nonmagnetic back layer.Type: ApplicationFiled: November 22, 2005Publication date: April 6, 2006Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
-
Publication number: 20060067017Abstract: A spin valve type magnetoresistive effect element for vertical electric conduction includes a magnetoresistive effect film in which a resistance adjustment layer made of a material containing conductive carriers not more than 1022/cm3 is inserted. Thus the resistance value of a portion in change of spin-relied conduction is raised to an adequate value, thereby to increase the resistance variable amount.Type: ApplicationFiled: November 21, 2005Publication date: March 30, 2006Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hiromi Yuasa, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Masashi Sahashi
-
Patent number: 7008702Abstract: A magnetoresistance effect element includes a nonmagnetic spacer layer, first and second ferromagnetic layer separated by the nonmagnetic spacer layer, and a nonmagnetic conductivity layer. The first ferromagnetic layer has a magnetization direction at an angle relative to a magnetization direction of the second ferromagnetic layer at zero applied magnetic field. The second ferromagnetic layer has first and second ferromagnetic films antiferromagnetically coupled to one another and an antiferromagnetically coupling film located between and in contact with the first and second ferromagnetic films. The magnetization of the first ferromagnetic layer freely rotates in a magnetic field signal. The nonmagnetic conductivity layer is disposed in contact with the first ferromagnetic layer so that the first ferromagnetic layer is disposed between the nonmagnetic high-conductivity layer and the nonmagnetic spacer layer. The first ferromagnetic layer has a film thickness between 0.5 nanometers and 4.5 nanometers.Type: GrantFiled: October 10, 2001Date of Patent: March 7, 2006Assignee: Kabushiki Kaisha ToshibaInventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
-
Publication number: 20060034022Abstract: The present invention relates to a method for manufacturing a magnetoresistive element having a magnetization pinned layer, a magnetization free layer, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer. A process of forming the spacer layer in the method includes depositing a first metal layer forming the metal paths, depositing a second metal layer on the first metal layer, performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas, and converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.Type: ApplicationFiled: August 9, 2005Publication date: February 16, 2006Inventors: Hideaki Fukuzawa, Katsuhiko Koui, Hiromi Yuasa, Susumu Hashimoto, Hitoshi Iwasaki
-
Patent number: 6937446Abstract: There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, a resistance regulating layer is provided in at least one of a pinned layer, a free layer and an non-magnetic intermediate layer. The resistance regulating layer contains, as a principal component, an oxide, a nitride, a fluoride, a carbide or a boride. The resistance regulating layer may be a continuous film or may have pin holes. Thus, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.Type: GrantFiled: October 19, 2001Date of Patent: August 30, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
-
Publication number: 20050167770Abstract: Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween.Type: ApplicationFiled: March 15, 2005Publication date: August 4, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
-
Publication number: 20050157433Abstract: There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, a resistance regulating layer is provided in at least one of a pinned layer, a free layer and an non-magnetic intermediate layer. The resistance regulating layer contains, as a principal component, an oxide, a nitride, a fluoride, a carbide or a boride. The resistance regulating layer may be a continuous film or may have pin holes. Thus, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.Type: ApplicationFiled: March 16, 2005Publication date: July 21, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Yuuzo Kamiguchi, Hiromi Yuasa, Tomohiko Nagata, Hiroaki Yoda, Katsuhiko Koui, Masatoshi Yoshikawa, Hitoshi Iwasaki, Masashi Sahashi, Masayuki Takagishi
-
Publication number: 20050141144Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer, and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.Type: ApplicationFiled: February 22, 2005Publication date: June 30, 2005Applicant: Kabushiki Kaisha ToshibaInventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
-
Publication number: 20050135018Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.Type: ApplicationFiled: February 22, 2005Publication date: June 23, 2005Applicant: Kabushiki Kaisha ToshibaInventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
-
Publication number: 20050128650Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film. The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.Type: ApplicationFiled: January 31, 2005Publication date: June 16, 2005Applicant: Kabushiki Kaisha ToshibaInventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki
-
Publication number: 20050052787Abstract: A magnetoresistance effect element of the dual spin valve type using a current-perpendicular-to-the-plane (CPP) system where a sensing current flows perpendicular to the stacked faces of a plurality of conductive layers, the magnetoresistance effect element comprises a first unit which includes a free layer and a first pinning layer, a second unit which includes the free layer shared with the first unit and a second pinning layer, a first current control layer which is provided in the first unit and limits the flow quantity of the sensing current, and a second current control layer which is provided in the second unit and limits the flow quantity of the sensing current.Type: ApplicationFiled: September 9, 2004Publication date: March 10, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomomi Funayama, Masayuki Takagishi, Katsuhiko Koui, Kohichi Tateyama
-
Publication number: 20050030676Abstract: Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween.Type: ApplicationFiled: September 10, 2004Publication date: February 10, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatoshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
-
Publication number: 20040246634Abstract: In a spin valve type element, an interface insertion layer (32, 34) of a material exhibiting large spin-dependent interface scattering is inserted in a location of a magnetically pinned layer (16) or a magnetically free layer (20) closer to a nonmagnetic intermediate layer (18). A nonmagnetic back layer (36) may be additionally inserted as an interface not in contact with the nonmagnetic intermediate layer to increase the output by making use of spin-dependent interface scattering along the interface between the pinned layer and the nonmagnetic back layer or between the free layer and the nonmagnetic back layer.Type: ApplicationFiled: July 9, 2004Publication date: December 9, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
-
Publication number: 20040201929Abstract: 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: ApplicationFiled: September 11, 2003Publication date: October 14, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Susumu Hashimoto, Katsuhiko Koui, Masashi Sahashi, Hitoshi Iwasaki
-
Patent number: 6784509Abstract: In a spin valve type element, an interface insertion layer (32, 34) of a material exhibiting large spin-dependent interface scattering is inserted in a location of a magnetically pinned layer (16) or a magnetically free layer (20) closer to a nonmagnetic intermediate layer (18). A nonmagnetic back layer (36) may be additionally inserted as an interface not in contact with the nonmagnetic intermediate layer to increase the output by making use of spin-dependent interface scattering along the interface between the pinned layer and the nonmagnetic back layer or between the free layer and the nonmagnetic back layer.Type: GrantFiled: August 14, 2002Date of Patent: August 31, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Hiromi Yuasa, Yuzo Kamiguchi, Masatoshi Yoshikawa, Katsuhiko Koui, Hitoshi Iwasaki, Tomohiko Nagata, Takeo Sakakubo, Masashi Sahashi
-
Publication number: 20040121185Abstract: Disclosed are a high-sensitivity and high-reliability magnetoresistance effect device (MR device) in which bias point designing is easy, and also a magnetic head, a magnetic head assembly and a magnetic recording/reproducing system incorporating the MR device. In the MR device incorporating a spin valve film, the magnetization direction of the free layer is at a certain angle to the magnetization direction of a second ferromagnetic layer therein when the applied magnetic field is zero. In this, the pinned magnetic layer comprises a pair of ferromagnetic films as antiferromagnetically coupled to each other via a coupling film existing therebetween.Type: ApplicationFiled: October 10, 2001Publication date: June 24, 2004Applicant: Kabushiki Kaisha ToshibaInventors: Hideaki Fukuzawa, Yuzo Kamiguchi, Katsuhiko Koui, Shin-ichi Nakamura, Hitoshi Iwasaki, Kazuhiro Saito, Hiromi Fuke, Masatshi Yoshikawa, Susumu Hashimoto, Masashi Sahashi
-
Magnetoresistance effect element, magnetic head, magnetic reproducing apparatus, and magnetic memory
Publication number: 20040021990Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film, The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer.Type: ApplicationFiled: March 28, 2003Publication date: February 5, 2004Applicant: Kabushiki Kaisha ToshibaInventors: Katsuhiko Koui, Masatoshi Yoshikawa, Masayuki Takagishi, Masashi Sahashi, Takeo Sakakubo, Hitoshi Iwasaki