Patents by Inventor Norikazu Ohshima
Norikazu Ohshima 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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Publication number: 20110298067Abstract: A magnetoresistive effect element includes: a magnetization free layer; a non-magnetic insertion layer provided adjacent to the magnetization free layer; a magnetic insertion layer provided adjacent to the non-magnetic insertion layer and opposite to the magnetization free layer with respect to the non-magnetic insertion layer; a spacer layer provided adjacent to the magnetic insertion layer and opposite to the non-magnetic insertion layer with respect to the magnetic insertion layer; and a first magnetization fixed layer provided adjacent to the spacer layer and opposite to the magnetic insertion layer with respect to the spacer layer. The magnetization free layer and the first magnetization fixed layer have magnetization components in directions approximately perpendicular to a film surface. The magnetization free layer includes two magnetization fixed portions and a domain wall motion portion arranged between the two magnetization fixed portions.Type: ApplicationFiled: February 15, 2010Publication date: December 8, 2011Applicant: NEC CORPORATIONInventors: Nobuyuki Ishiwata, Norikazu Ohshima, Shunsuke Fukami, Kiyokazu Nagahara, Tetsuhiro Suzuki
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Publication number: 20110297909Abstract: A magnetic memory element includes: a first magnetization free layer formed of a ferromagnetic material having perpendicular magnetic anisotropy; a second magnetization free layer provided near the first magnetization free layer and formed of a ferromagnetic material having in-plane magnetic anisotropy; a reference layer formed of a ferromagnetic material having in-plane magnetic anisotropy; and a non-magnetic layer provided between the second magnetization free layer and the reference layer. The first magnetization free layer includes: a first magnetization fixed region of which magnetization is fixed, a second magnetization fixed region of which magnetization is fixed, and a magnetization free region which is connected to the first magnetization fixed region and the second magnetization fixed region, and of which magnetization can be switched. The second magnetization free layer is included in the first magnetization free layer in a plane parallel to a substrate.Type: ApplicationFiled: January 28, 2010Publication date: December 8, 2011Inventors: Shunsuke Fukami, Tetsuhiro Suzuki, Kiyokazu Nagahara, Nobuyuki Ishiwata, Norikazu Ohshima
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Publication number: 20110267879Abstract: A magnetic memory cell includes: a magnetization recording layer; and a magnetic tunneling junction section. The magnetization recording layer includes a ferromagnetic layer with perpendicular magnetic anisotropy. The magnetic tunneling junction section is used for reading information in the magnetization recording layer. The magnetization recording layer includes two domain wall moving areas.Type: ApplicationFiled: December 24, 2009Publication date: November 3, 2011Applicant: NEC CORPORATIONInventors: Kiyokazu Nagahara, Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima
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Publication number: 20110260273Abstract: A magnetic memory cell is provided with a magnetization record layer and a magnetic tunnel junction section. The magnetization record layer is a ferromagnetic layer having a perpendicular magnetic anisotropy. The magnetic tunnel junction section is used to read data from the magnetization record layer. The magnetization record layer has a plurality of domain wall motion regions.Type: ApplicationFiled: December 24, 2009Publication date: October 27, 2011Inventors: Shunsuke Fukami, Kiyokazu Nagahara, Tetsuhiro Suzuki, Nobuyuki Ishiwata, Norikazu Ohshima
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Patent number: 8040724Abstract: A magnetic random access memory includes: a magnetic recording layer including a ferromagnetic layer and having perpendicular magnetic anisotropy; and a magnetic reading layer provided on the magnetic recording layer and used for reading information. The magnetic recording layer includes: a magnetization switching area having reversible magnetization; a first magnetization pinned area connected to a first boundary of the magnetization switching area and having magnetization whose direction is pinned in a first direction; and a second magnetization pinned area connected to a second boundary of the magnetization switching area and having magnetization whose direction is pinned in a second direction. The magnetic reading layer includes: a magnetic sensing layer whose direction of magnetization changes based on a direction of the magnetization of the magnetization switching area; a nonmagnetic barrier layer provided on the magnetic sensing layer; and a pinned layer provided on the nonmagnetic barrier layer.Type: GrantFiled: July 7, 2008Date of Patent: October 18, 2011Assignee: NEC CorporationInventors: Tetsuhiro Suzuki, Norikazu Ohshima, Shunsuke Fukami, Kiyokazu Nagahara, Nobuyuki Ishiwata
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Publication number: 20110188298Abstract: A magnetoresistance element is provided with: a magnetization recording layer that is a ferromagnetic layer. The magnetization recording layer includes: a magnetization reversal region having a reversible magnetization; a first magnetization fixed region connected to a first boundary of the magnetization reversal region and having a magnetization direction fixed in a first direction; and a second magnetization fixed region connected to a second boundary of the magnetization reversal region and having a magnetization direction fixed in a second direction. At least one magnetization reversal facilitation structure which is a structure in which a magnetization is reversed more easily than the remaining portion is provided for a portion of the second magnetization fixed region.Type: ApplicationFiled: October 16, 2009Publication date: August 4, 2011Inventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Norikazu Ohshima, Nobuyuki Ishiwata
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Publication number: 20110157967Abstract: A magnetic memory includes a magnetization recording layer, a first terminal, a second terminal, a magnetization pinned layer and a non-magnetic layer. The magnetization recording layer has a vertical magnetic anisotropy and includes a ferromagnetic layer. The first terminal is connected to one end of a first region in the magnetization recording layer. The second terminal is connected to the other end of the first region. The non-magnetic layer is arranged on the first region. The magnetization pinned layer is arranged on the non-magnetic layer and is located on the side opposite to the first region. The magnetization recording layer includes: a first extension portion located outside the first terminal in the magnetization recording layer; and a property changing structure that is arranged in the first extension portion and substantially changes a magnetization switching property of the magnetization recording layer.Type: ApplicationFiled: June 26, 2009Publication date: June 30, 2011Applicant: NEC CorporationInventors: Tetsuhiro Suzuki, Shunsuke Fukami, Kiyokazu Nagahara, Norikazu Ohshima, Nobuyuki Ishiwata
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Publication number: 20110129691Abstract: A domain wall motion element has a magnetic recording layer 10 that is formed of a ferromagnetic film and has a domain wall DW. The magnetic recording layer 10 has: a pair of end regions 11-1 and 11-2 whose magnetization directions are fixed; and a center region 12 sandwiched between the pair of end regions 11-1 and 11-2, in which the domain wall. DW moves. A first trapping site TS1 by which the domain wall DW is trapped is formed at a boundary between the end region 11-1, 11-2 and the center region 12. Furthermore, at least one second trapping site TS2 by which the domain wall DW is trapped is formed within the center region 12.Type: ApplicationFiled: January 13, 2009Publication date: June 2, 2011Inventors: Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima, Kiyokazu Nagahara, Shunsuke Fukami
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Patent number: 7929342Abstract: The present invention provides a new data writing method for an MRAM which can suppress deterioration of a tunnel barrier layer. A magnetic memory cell 1 has a magnetic recording layer 10 and a pinned layer 30 connected to the magnetic recording layer 10 through a non-magnetic layer 20. The magnetic recording layer 10 includes a magnetization switching region 13, a first magnetization fixed region 11 and a second magnetization fixed region 12. The magnetization switching region 13 has reversible magnetization and faces the pinned layer 30. The first magnetization fixed region 11 is connected to a first boundary B1 of the magnetization switching region 13 and its magnetization direction is fixed to a first direction. The second magnetization fixed region 12 is connected to a second boundary B2 of the magnetization switching region 13 and its magnetization direction is fixed to a second direction.Type: GrantFiled: August 4, 2006Date of Patent: April 19, 2011Assignee: NEC CorporationInventors: Hideaki Numata, Norikazu Ohshima, Tetsuhiro Suzuki, Tadahiko Sugibayashi, Nobuyuki Ishiwata, Shunsuke Fukami
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Publication number: 20110002163Abstract: A semiconductor device includes: a first magnetic random access memory including a first memory cell and a second magnetic random access memory including a second memory cell operating at higher speed than the first memory cell and is provided on the same chip together with the first magnetic random access memory. The first memory cell is a current-induced domain wall motion type MRAM and stores data based on a domain wall position of a magnetization free layer. A layer that a write current flows is different from a layer that a read current flows. The second memory cell is a current-induced magnetic field writing type MRAM and stores data based on a magnetic field induced by a write current.Type: ApplicationFiled: March 5, 2009Publication date: January 6, 2011Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima, Kiyokazu Nagahara
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Publication number: 20100315854Abstract: A domain wall motion type MRAM has: a magnetic recording layer 10 having perpendicular magnetic anisotropy; and a pair of terminals 51 and 52 used for supplying a current to the magnetic recording layer 10. The magnetic recording layer 10 has: a first magnetization region 11 connected to one of the pair of terminals; a second magnetization region 12 connected to the other of the pair of terminals; and a magnetization switching region 13 connecting between the first magnetization region 11 and the second magnetization region 12 and having reversible magnetization. A first pinning site PS1, by which the domain wall is trapped, is formed at a boundary between the first magnetization region 11 and the magnetization switching region 13. A second pinning site PS2, by which the domain wall is trapped, is formed at a boundary between the second magnetization region 12 and the magnetization switching region 13.Type: ApplicationFiled: December 10, 2008Publication date: December 16, 2010Inventors: Tetsuhiro Suzuki, Shunsuke Fukami, Norikazu Ohshima, Kiyokazu Nagahara, Nobuyuki Ishiwata
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Publication number: 20100309712Abstract: An MRAM has: a memory cell including a first magnetoresistance element; and a reference cell including a second magnetoresistance element. The first magnetoresistance element has a first magnetization free layer, a first magnetization fixed layer, a second magnetization free layer and a first nonmagnetic layer sandwiched between the first magnetization fixed layer and the second magnetization free layer. The first magnetization free layer has perpendicular magnetic anisotropy, and the first magnetization fixed layer and the second magnetization free layer has in-plane magnetic anisotropy. The first magnetization free layer has: first and second magnetization fixed regions whose magnetization directions are fixed; and a magnetization free region whose magnetization direction is reversible and connected to the first and second magnetization fixed regions. The magnetization free region and the second magnetization free layer are magnetically coupled to each other.Type: ApplicationFiled: January 9, 2009Publication date: December 9, 2010Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima, Kiyokazu Nagahara
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Publication number: 20100309713Abstract: An MRAM has: a memory cell including a first magnetoresistance element; and a reference cell including a second magnetoresistance element. The first magnetoresistance element has a first magnetization fixed layer, a first magnetization free layer, a first nonmagnetic layer sandwiched between the first magnetization fixed layer and the first magnetization free layer, a second magnetization fixed layer, a second magnetization free layer and a second nonmagnetic layer sandwiched between the second magnetization fixed layer and the second magnetization free layer. The first magnetization fixed layer and the first magnetization free layer have perpendicular magnetic anisotropy, and the second magnetization fixed layer and the second magnetization free layer have in-plane magnetic anisotropy. The first magnetization free layer and the second magnetization free layer are magnetically coupled to each other.Type: ApplicationFiled: January 9, 2009Publication date: December 9, 2010Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima, Kiyokazu Nagahara
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Publication number: 20100254183Abstract: A magnetoresistance effect element has: a first magnetization fixed layer whose magnetization direction is fixed; a first magnetization free layer whose magnetization direction is variable; a first nonmagnetic layer sandwiched between the first magnetization fixed layer and the first magnetization free layer; a second magnetization fixed layer whose magnetization direction is fixed; a second magnetization free layer whose magnetization direction is variable; and a second nonmagnetic layer sandwiched between the second magnetization fixed layer and the second magnetization free layer. The first magnetization fixed layer and the first magnetization free layer have perpendicular magnetic anisotropy, while the second magnetization fixed layer and the second magnetization free layer have in-plane magnetic anisotropy. The first magnetization free layer and the second magnetization free layer are magnetically coupled to each other.Type: ApplicationFiled: August 21, 2008Publication date: October 7, 2010Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Norikazu Ohshima, Kiyokazu Nagahara
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Publication number: 20100237449Abstract: A magnetoresistive element is provided with a first magnetization free layer; a second magnetization free layer; a non-magnetic layer disposed adjacent to the second magnetization free layer; and a first magnetization fixed layer disposed adjacent to the second magnetization free layer on an opposite side of the second magnetization free layer. The first magnetization free layer is formed of ferromagnetic material and has a magnetic anisotropy in a thickness direction. On the other hand, the second magnetization free layer and the first magnetization fixed layer are formed of ferromagnetic material and have a magnetic anisotropy in an in-plane direction. The first magnetization free layer includes: a first magnetization fixed region having a fixed magnetization; a second magnetization fixed region having a fixed magnetization; and a magnetization free region connected to the first and second magnetization fixed regions and having a reversible magnetization.Type: ApplicationFiled: October 28, 2008Publication date: September 23, 2010Inventors: Shunsuke Fukami, Nobuyuki Ishiwata, Tetsuhiro Suzuki, Kiyokazu Nagahara, Norikazu Ohshima
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Publication number: 20100214826Abstract: A magnetic random access memory includes: a first ferromagnetic layet; an insulating layer provided adjacent to the first ferromagnetic layer; and a first magnetization pinned layer provided adjacent to the insulating layer on a side opposite to the first ferromagnetic layer. The first ferromagnetic layer includes a magnetization free region, a first magnetization pinned region, and a second magnetization pinned region. The magnetization free region has reversible magnetization, and overlaps with the second ferromagnetic layer. The first magnetization pinned region has first pinned magnetization, and is connected to a part of the magnetization free region. The second magnetization pinned region has second pinned magnetization, and is connected to a part of the magnetization free region. The first ferromagnetic layer has magnetic anisotropy in a direction perpendicular to a film surface.Type: ApplicationFiled: July 7, 2008Publication date: August 26, 2010Applicant: NEC CORPORATIONInventors: Shunsuke Fukami, Tetsuhiro Suzuki, Kiyokazu Nagahara, Norikazu Ohshima, Nobuyuki Ishiwata
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Publication number: 20100193890Abstract: A magnetic random access memory includes: a magnetic recording layer including a ferromagnetic layer and having perpendicular magnetic anisotropy; and a magnetic reading layer provided on the magnetic recording layer and used for reading information. The magnetic recording layer includes: a magnetization switching area having reversible magnetization; a first magnetization pinned area connected to a first boundary of the magnetization switching area and having magnetization whose direction is pinned in a first direction; and a second magnetization pinned area connected to a second boundary of the magnetization switching area and having magnetization whose direction is pinned in a second direction. The magnetic reading layer includes: a magnetic sensing layer whose direction of magnetization changes based on a direction of the magnetization of the magnetization switching area; a nonmagnetic barrier layer provided on the magnetic sensing layer; and a pinned layer provided on the nonmagnetic barrier layer.Type: ApplicationFiled: July 7, 2008Publication date: August 5, 2010Inventors: Tetsuhiro Suzuki, Norikazu Ohshima, Shunsuke Fukami, Kiyokazu Nagahara, Nobuyuki Ishiwata
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Publication number: 20100193889Abstract: A domain wall motion type MRAM 100 has: a magnetic recording layer 10 that is a ferromagnetic layer; and a magnetic coupling layer 20 that is a ferromagnetic layer whose magnetization direction is fixed. The magnetic recording layer 10 has: a first region 10-1; a second region 10-2; and a magnetization switching region 10-3 connecting between the first region 10-1 and the second region 10-2. The first region 10-1 is magnetically coupled to the magnetic coupling layer 20 and its magnetization direction is fixed in a first direction by the magnetic coupling layer 20. The second region 10-2 is not magnetically coupled to the magnetic coupling layer 20 and its magnetization direction is a second direction that is opposite to the first direction.Type: ApplicationFiled: July 7, 2008Publication date: August 5, 2010Inventors: Kiyokazu Nagahara, Shunsuke Fukami, Tetsuhiro Suzuki, Norikazu Ohshima, Nobuyuki Ishiwata
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Publication number: 20100149862Abstract: A magnetic random access memory comprises a magnetic recording layer equipped with a magnetization reversal region having a reversible magnetization and through which a write current is made to flow in the in-plane direction, a magnetization fixed layer having a fixed magnetization, a nonmagnetic layer provided between the magnetization reversal region and the magnetization fixed layer, and a heat absorbing structure provided opposing to the magnetic recording layer and having a function of receiving heat generated in the magnetic recording layer and of radiating the heat. Such magnetic random access memory can radiate heat generated in the magnetic recording layer by using the heat absorbing structure and prevent temperature rising caused by the write current flowing in the in-plane direction.Type: ApplicationFiled: April 9, 2007Publication date: June 17, 2010Applicant: NEC CORPORATIONInventors: Nobuyuki Ishiwata, Hideaki Numata, Norikazu Ohshima
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Publication number: 20100142264Abstract: The present invention provides a new data writing method for an MRAM which can suppress deterioration of a tunnel barrier layer. A magnetic memory cell 1 has a magnetic recording layer 10 and a pinned layer 30 connected to the magnetic recording layer 10 through a non-magnetic layer 20. The magnetic recording layer 10 includes a magnetization switching region 13, a first magnetization fixed region 11 and a second magnetization fixed region 12. The magnetization switching region 13 has reversible magnetization and faces the pinned layer 30. The first magnetization fixed region 11 is connected to a first boundary B1 of the magnetization switching region 13 and its magnetization direction is fixed to a first direction. The second magnetization fixed region 12 is connected to a second boundary B2 of the magnetization switching region 13 and its magnetization direction is fixed to a second direction.Type: ApplicationFiled: August 4, 2006Publication date: June 10, 2010Applicant: NEC CORPORATIONInventors: Hideaki Numata, Norikazu Ohshima, Tetsuhiro Suzuki, Tadahiko Sugibayashi, Nobuyuki Ishiwata, Shunsuke Fukami