Patents by Inventor Masahiro Takashita
Masahiro Takashita 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: 9222994Abstract: A method for measuring the frequency in a spin torque oscillator having at least a magnetic oscillation layer (MOL), junction layer, and magnetic reference layer (MRL) is disclosed. In a first embodiment, a small in-plane magnetic field is applied to the STO after a DC current is applied to excite the MOL into an oscillation state. The MRL has a perpendicular magnetization that is tilted slightly to give an in-plane magnetization component to serve as a reference layer for measuring the oscillation frequency of the MOL in-plane magnetization component. An AC voltage change is produced in the DC current as a result of variable STO resistance and directly correlates to MOL oscillation frequency. Alternatively, a field having both perpendicular and in-plane components may be applied externally or by forming the STO between two magnetic poles thereby producing an in-plane magnetization reference component in the MRL.Type: GrantFiled: September 19, 2011Date of Patent: December 29, 2015Assignees: TDK Corporation, Kabushiki Kaisha ToshibaInventors: Yuchen Zhou, Kunliang Zhang, Min Li, Kenichi Takano, Joe Smyth, Moris Dovek, Akihiko Takeo, Tomomi Funayama, Masahiro Takashita, Masayuki Takagishi
-
Patent number: 8995089Abstract: According to one embodiment, there is provided a magnetic recording medium which includes a base, a magnetic recording layer having convex-shaped magnetic layers, which is formed on the base, and a protective film formed on the magnetic recording layer. There are gaps in a region surrounded by the protective film, the surface of the base, and each side wall of each magnetic layer.Type: GrantFiled: July 17, 2013Date of Patent: March 31, 2015Assignee: Kabushiki Kaisha ToshibaInventors: Kazutaka Takizawa, Akira Watanabe, Kaori Kimura, Tsuyoshi Onitsuka, Takeshi Iwasaki, Masahiro Takashita, Akihiko Takeo
-
Patent number: 8970986Abstract: A magnetic head includes a main magnetic pole, a trailing shield that forms a magnetic circuit with the main magnetic pole, a spin torque oscillator that is provided between the main magnetic pole and the trailing shield, a first cooling layer that partially has a Heusler structure, and a second cooling layer that is provided on the first cooling layer and mainly comprised of silver. The first cooling layer and the second cooling layer are provided either between the main magnetic pole and spin torque oscillator or between the trailing shield and the spin torque oscillator, with either of the two cooling layers being disposed closer to the spin torque oscillator. A third cooling layer may be formed to be in contact with the first cooling layer.Type: GrantFiled: June 11, 2013Date of Patent: March 3, 2015Assignee: Kabushiki Kaisha ToshibaInventors: Masahiro Takashita, Shuichi Murakami, Naoki Hase, Katsuhiko Koui
-
Patent number: 8896947Abstract: According to one embodiment, a disk storage apparatus includes a magnetic head, a detector, a calculator, and a decision module. The magnetic head has a high-frequency assisted element disposed close to a main magnetic pole that generates a recording magnetic field for perpendicular magnetic recording, the high-frequency assisted element applying a high-frequency magnetic field onto a magnetic disk during data recording. The detector detects an electrical resistance of the high-frequency assisted element. The calculator calculates time axis data indicative of a variation, on a time axis, in the electrical resistance value detected by the detector. The decision module determines whether the high-frequency assisted elements is malfunctioning based on the time axis data.Type: GrantFiled: May 22, 2013Date of Patent: November 25, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Gaku Koizumi, Masahiro Takashita, Tomoko Taguchi
-
Patent number: 8879206Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole, an auxiliary magnetic pole, and a spin torque oscillator formed between them. The spin torque oscillator includes a main oscillation layer and spin sink layer as an oscillation layer. The spin sink layer contains one of iron and cobalt, and at least one element selected from the group consisting of platinum, palladium, ruthenium, tantalum, chromium, terbium, gadolinium, europium, dysprosium, and samarium.Type: GrantFiled: December 17, 2012Date of Patent: November 4, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Mariko Shimizu, Katsuhiko Koui, Shuichi Murakami, Masahiro Takashita
-
Publication number: 20140247519Abstract: According to one embodiment, there is provided a magnetic recording medium which includes a base, a magnetic recording layer having convex-shaped magnetic layers, which is formed on the base, and a protective film formed on the magnetic recording layer. There are gaps in a region surrounded by the protective film, the surface of the base, and each side wall of each magnetic layer.Type: ApplicationFiled: July 17, 2013Publication date: September 4, 2014Inventors: Kazutaka Takizawa, Akira Watanabe, Kaori Kimura, Tsuyoshi Onitsuka, Takeshi Iwasaki, Masahiro Takashita, Akihiko Takeo
-
Publication number: 20140168808Abstract: According to one embodiment, a disk storage apparatus includes a magnetic head, a detector, a calculator, and a decision module. The magnetic head has a high-frequency assisted element disposed close to a main magnetic pole that generates a recording magnetic field for perpendicular magnetic recording, the high-frequency assisted element applying a high-frequency magnetic field onto a magnetic disk during data recording. The detector detects an electrical resistance of the high-frequency assisted element. The calculator calculates time axis data indicative of a variation, on a time axis, in the electrical resistance value detected by the detector. The decision module determines whether the high-frequency assisted elements is malfunctioning based on the time axis data.Type: ApplicationFiled: May 22, 2013Publication date: June 19, 2014Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Gaku Koizumi, Masahiro Takashita, Tomoko Taguchi
-
Publication number: 20140160598Abstract: A magnetic head includes a main magnetic pole, a trailing shield that forms a magnetic circuit with the main magnetic pole, a spin torque oscillator that is provided between the main magnetic pole and the trailing shield, a first cooling layer that partially has a Heusler structure, and a second cooling layer that is provided on the first cooling layer and mainly comprised of silver. The first cooling layer and the second cooling layer are provided either between the main magnetic pole and spin torque oscillator or between the trailing shield and the spin torque oscillator, with either of the two cooling layers being disposed closer to the spin torque oscillator. A third cooling layer may be formed to be in contact with the first cooling layer.Type: ApplicationFiled: June 11, 2013Publication date: June 12, 2014Inventors: Masahiro TAKASHITA, Shuichi MURAKAMI, Naoki HASE, Katsuhiko KOUI
-
Patent number: 8654480Abstract: An example magnetic head includes a recording pole to generate a recording magnetic field, a spin torque oscillator formed in the vicinity of the recording magnetic pole and a hard bias film provided at both end portions of a bias layer and an oscillation layer of spin torque oscillator. The hard bias film is configured to apply a magnetic field to the bias layer and the oscillation layer.Type: GrantFiled: July 10, 2012Date of Patent: February 18, 2014Assignee: Kabushiki Kaisha ToshibaInventors: Mariko Shimizu, Hitoshi Iwasaki, Kenichiro Yamada, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita
-
Publication number: 20130329317Abstract: An example magnetic writing head includes a main magnetic pole and a coil to generate an ampere magnetic field to magnetize the main magnetic pole to cause the magnetized main magnetic pole to generate a magnetic field. The laminated body includes a first magnetic layer, and a second magnetic layer.Type: ApplicationFiled: August 13, 2013Publication date: December 12, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Kenichiro YAMADA, Hitoshi IWASAKI, Junichi AKIYAMA, Masayuki TAKAGISHI, Tomomi FUNAYAMA, Masahiro TAKASHITA, Mariko SHIMIZU, Shuichi MURAKAMI, Tadashi KAI
-
Publication number: 20130314820Abstract: According to one embodiment, a magnetic recording head includes a main magnetic pole, an auxiliary magnetic pole, and a spin torque oscillator formed between them. The spin torque oscillator includes a main oscillation layer and spin sink layer as an oscillation layer. The spin sink layer contains one of iron and cobalt, and at least one element selected from the group consisting of platinum, palladium, ruthenium, tantalum, chromium, terbium, gadolinium, europium, dysprosium, and samarium.Type: ApplicationFiled: December 17, 2012Publication date: November 28, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Mariko SHIMIZU, Katsuhiko KOUI, Shuichi MURAKAMI, Masahiro TAKASHITA
-
Patent number: 8553359Abstract: A magnetic recording head includes a magnetic pole, a spin torque oscillator, a first shield and a second shield. The magnetic pole has an air-bearing surface. The spin torque oscillator is provided so that a first side of the spin torque oscillator faces the magnetic pole in a first direction parallel to the air-bearing surface. The first shield includes a granular magnetic material, and is provided so that two portions of the first shield sandwich the spin torque oscillator in a second direction which is parallel to the air-bearing surface and perpendicular to the first direction. The second shield is provided on a second side of the spin torque oscillator opposite to the first side.Type: GrantFiled: August 10, 2010Date of Patent: October 8, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Kenichiro Yamada, Katsuhiko Koui, Mariko Kitazaki, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Soichi Oikawa, Akihiko Takeo
-
Patent number: 8547662Abstract: An example magnetic writing head includes a main magnetic pole, a coil to generate an ampere magnetic field to magnetize the main magnetic pole to cause the magnetized main magnetic pole to generate a magnetic field, and a laminated body. The laminated body includes a first magnetic layer having a coercivity lower than the magnetic field applied by the main magnetic pole and a second magnetic layer having a coercivity lower than the magnetic field applied by the main magnetic pole.Type: GrantFiled: July 3, 2012Date of Patent: October 1, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Kenichiro Yamada, Hitoshi Iwasaki, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Shuichi Murakami, Tadashi Kai
-
Patent number: 8472140Abstract: A magnetic recorder includes: a magnetic recording medium; a reproducing head; a magnetic recording head including: a main magnetic pole; a first magnetic layer containing a TM alloy; a second magnetic layer containing a TM alloy or an RE-TM alloy; a third magnetic layer containing an RE-TM alloy; a first intermediate layer provided between the first magnetic layer and the second magnetic layer; and a second intermediate layer provided between the second magnetic layer and the third magnetic layer; and a signal processing portion which performs signal writing into the magnetic recording medium by using the magnetic recording head and reading from the magnetic recording medium by using the reproducing head.Type: GrantFiled: February 24, 2012Date of Patent: June 25, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Kenichiro Yamada, Hitoshi Iwasaki, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Katsuhiko Koui, Mariko Kitazaki, Soichi Oikawa
-
Patent number: 8467150Abstract: According to one embodiment, a recording head includes a main pole configured to apply a recording magnetic field to a recording medium, a trailing shield opposed to the main pole with a gap therebetween, a spin-torque oscillator at least a part of which is located between the main pole and the trailing shield and configured to apply a high-frequency magnetic field to the recording medium, and an auxiliary oscillator configured to apply an auxiliary magnetic field to the spin-torque oscillator.Type: GrantFiled: February 29, 2012Date of Patent: June 18, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Akihiko Takeo, Masahiro Takashita
-
Patent number: 8446691Abstract: According to one embodiment, a magnetic recording device includes a magnetic recording head and a magnetic recording medium. The magnetic recording head includes a main magnetic pole, a shield and a stacked structure. The main magnetic pole has a medium facing surface and a main magnetic pole side surface. The shield has a shield side surface. The stacked structure is provided between the main magnetic pole and shield, and includes first and second magnetic layers, and an intermediate layer. The magnetic recording medium includes a backing layer and a magnetic recording layer. A distance between an end portion of the medium facing surface on a side of the stacked structure and the backing layer is twice or more of a distance between the main magnetic pole side surface and the shield side surface.Type: GrantFiled: April 30, 2012Date of Patent: May 21, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Masayuki Takagishi, Hitoshi Iwasaki, Kenichiro Yamada, Katsuhiko Koui, Tomomi Funayama, Masahiro Takashita, Mariko Kitazaki, Soichi Oikawa
-
Publication number: 20130069626Abstract: A method for measuring the frequency in a spin torque oscillator having at least a magnetic oscillation layer (MOL), junction layer, and magnetic reference layer (MRL) is disclosed. In a first embodiment, a small in-plane magnetic field is applied to the STO after a DC current is applied to excite the MOL into an oscillation state. The MRL has a perpendicular magnetization that is tilted slightly to give an in-plane magnetization component to serve as a reference layer for measuring the oscillation frequency of the MOL in-plane magnetization component. An AC voltage change is produced in the DC current as a result of variable STO resistance and directly correlates to MOL oscillation frequency. Alternatively, a field having both perpendicular and in-plane components may be applied externally or by forming the STO between two magnetic poles thereby producing an in-plane magnetization reference component in the MRL.Type: ApplicationFiled: September 19, 2011Publication date: March 21, 2013Inventors: Yuchen Zhou, Kunliang Zhang, Min Li, Kenichi Takano, Joe Smyth, Moris Dovek, Akihiko Takeo, Tomomi Funayama, Masahiro Takashita, Masayuki Takagishi
-
Patent number: 8400734Abstract: An example magnetic recording head includes: a main magnetic pole; a laminated body; and a pair of electrodes. The laminated body includes a first magnetic layer having a coercivity lower than magnetic field applied by the main magnetic pole, a second magnetic layer having a coercivity lower than the magnetic field applied by the main magnetic pole, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. The pair of electrodes is operable to pass a current through the laminated body.Type: GrantFiled: August 19, 2011Date of Patent: March 19, 2013Assignee: Kabushiki Kaisha ToshibaInventors: Kenichiro Yamada, Hitoshi Iwasaki, Junichi Akiyama, Masayuki Takagishi, Tomomi Funayama, Masahiro Takashita, Mariko Shimizu, Shuichi Murakami, Tadashi Kai
-
Publication number: 20130062308Abstract: According to one embodiment, a method of manufacturing a magnetic recording head includes forming a main pole, forming an oscillator forming layer includes an underlayer, a spin injection layer, an interlayer, an oscillator layer, and a cap layer on a trailing end surface and sidewalls of the main pole, and removing those parts of the oscillator forming layer which are formed on the sidewalls of the main pole, thereby forming a high-frequency oscillator which is aligned with a width of at least the trailing end surface of the main pole.Type: ApplicationFiled: July 3, 2012Publication date: March 14, 2013Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tomomi FUNAYAMA, Masahiro TAKASHITA, Yusuke TOMODA
-
Publication number: 20120314326Abstract: According to one embodiment, a recording head includes a main pole configured to apply a recording magnetic field to a recording medium, a trailing shield opposed to the main pole with a gap therebetween, a spin-torque oscillator at least a part of which is located between the main pole and the trailing shield and configured to apply a high-frequency magnetic field to the recording medium, and an auxiliary oscillator configured to apply an auxiliary magnetic field to the spin-torque oscillator.Type: ApplicationFiled: February 29, 2012Publication date: December 13, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Akihiko TAKEO, Masahiro TAKASHITA