Patents by Inventor Yasunari Tajima
Yasunari Tajima 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: 7848064Abstract: An anti-parallel pinned sensor is provided with a spacer that increases the anti-parallel coupling strength of the sensor. The anti-parallel pinned sensor is a GMR or TMR sensor having a pure ruthenium or ruthenium alloy spacer. The thickness of the spacer is less than 0.8 nm, preferably between 0.1 and 0.6 nm. The spacer is also annealed in a magnetic field that is 1.5 Tesla or higher, and preferably greater than 5 Tesla. This design yields unexpected results by more than tripling the pinning field over that of typical AP-pinned GMR and TMR sensors that utilize ruthenium spacers which are 0.8 nm thick and annealed in a relatively low magnetic field of approximately 1.3 Tesla.Type: GrantFiled: July 11, 2008Date of Patent: December 7, 2010Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Wen-Yaung Lee, Jinshan Li, Daniele Mauri, Koichi Nishioka, Yasunari Tajima
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Patent number: 7474514Abstract: Exchange coupling energy between an anti-ferromagnetic layer and a first ferromagnetic layer, and an anti-ferromagnetic coupling energy between the first ferromagnetic layer and a second ferromagnetic layer by way of an Ru anti-ferromagnetic coupling layer of a spin valve device are increased thereby increasing the magnetoresistance ratio and decreasing the coercivity of the free layer of the spin valve film. In an MnPt anti-ferromagnetic bottom type synthetic ferri-type spin valve film in which an underlayer, an anti-ferromagnetic layer comprising MnPt, a first ferromagnetic layer comprising CoFe, an anti-ferromagnetic coupling layer comprising Ru, a second ferromagnetic layer comprising CoFe, an intermediate non-magnetic layer comprising Cu, a free layer comprising synthetic films of CoFe and NiFe and a protective layer are stacked over a substrate, the Fe composition X in CoFeX of the first ferromagnetic layer is set as about: 20<x?50 at %.Type: GrantFiled: June 29, 2005Date of Patent: January 6, 2009Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Kouichi Nishioka, Satoshi Shigematsu, Yasunari Tajima
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Publication number: 20080285182Abstract: An anti-parallel pinned sensor is provided with a spacer that increases the anti-parallel coupling strength of the sensor. The anti-parallel pinned sensor is a GMR or TMR sensor having a pure ruthenium or ruthenium alloy spacer. The thickness of the spacer is less than 0.8 nm, preferably between 0.1 and 0.6 nm. The spacer is also annealed in a magnetic field that is 1.5 Tesla or higher, and preferably greater than 5 Tesla. This design yields unexpected results by more than tripling the pinning field over that of typical AP-pinned GMR and TMR sensors that utilize ruthenium spacers which are 0.8 nm thick and annealed in a relatively low magnetic field of approximately 1.3 Tesla.Type: ApplicationFiled: July 11, 2008Publication date: November 20, 2008Inventors: Wen-Yaung Lee, Jinshan Li, Daniele Mauri, Koichi Nishioka, Yasunari Tajima
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Patent number: 7408747Abstract: An anti-parallel pinned sensor is provided with a spacer that increases the anti-parallel coupling strength of the sensor. The anti-parallel pinned sensor is a GMR or TMR sensor having a pure ruthenium or ruthenium alloy spacer. The thickness of the spacer is less than 0.8 nm, preferably between 0.1 and 0.6 nm. The spacer is also annealed in a magnetic field that is 1.5 Tesla or higher, and preferably greater than 5 Tesla. This design yields unexpected results by more than tripling the pinning field over that of typical AP-pinned GMR and TMR sensors that utilize ruthenium spacers which are 0.8 nm thick and annealed in a relatively low magnetic field of approximately 1.3 Tesla.Type: GrantFiled: February 1, 2005Date of Patent: August 5, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Wen-Yaung Lee, Jinshan Li, Daniele Mauri, Koichi Nishioka, Yasunari Tajima
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Patent number: 7209327Abstract: A magnetic domain control underlayer is formed below a magnetoresistive multi-layered film thereby bringing the magnetic domain control film into contact with both lateral end faces of a free layer and appropriate magnetic domain control can be attained in a state of minimizing a surplus bias magnetic field from the magnetic domain control film.Type: GrantFiled: September 30, 2003Date of Patent: April 24, 2007Assignee: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Norihiro Ookawa, Shuichi Kojima, Koji Okazaki, Satoshi Shigematsu, Yasunari Tajima
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Publication number: 20060171083Abstract: An anti-parallel pinned sensor is provided with a spacer that increases the anti-parallel coupling strength of the sensor. The anti-parallel pinned sensor is a GMR or TMR sensor having a pure ruthenium or ruthenium alloy spacer. The thickness of the spacer is less than 0.8 nm, preferably between 0.1 and 0.6 nm. The spacer is also annealed in a magnetic field that is 1.5 Tesla or higher, and preferably greater than 5 Tesla. This design yields unexpected results by more than tripling the pinning field over that of typical AP-pinned GMR and TMR sensors that utilize ruthenium spacers which are 0.8 nm thick and annealed in a relatively low magnetic field of approximately 1.3 Tesla.Type: ApplicationFiled: February 1, 2005Publication date: August 3, 2006Inventors: Wen-Yaung Lee, Jinshan Li, Daniele Mauri, Koichi Nishioka, Yasunari Tajima
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Publication number: 20060002040Abstract: Exchange coupling energy between an anti-ferromagnetic layer and a first ferromagnetic layer, and an anti-ferromagnetic coupling energy between the first ferromagnetic layer and a second ferromagnetic layer by way of an Ru anti-ferromagnetic coupling layer of a spin valve device are increased thereby increasing the magnetoresistance ratio and decreasing the coercivity of the free layer of the spin valve film. In an MnPt anti-ferromagnetic bottom type synthetic ferri-type spin valve film in which an underlayer, an anti-ferromagnetic layer comprising MnPt, a first ferromagnetic layer comprising CoFe, an anti-ferromagnetic coupling layer comprising Ru, a second ferromagnetic layer comprising CoFe, an intermediate non-magnetic layer comprising Cu, a free layer comprising synthetic films of CoFe and NiFe and a protective layer are stacked over a substrate, the Fe composition X in CoFeX of the first ferromagnetic layer is set as about: 20<x?50 at %.Type: ApplicationFiled: June 29, 2005Publication date: January 5, 2006Applicant: Hitachi Glogal Storage Technologies Netherlands B.V.Inventors: Kouichi Nishioka, Satoshi Shigematsu, Yasunari Tajima
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Patent number: 6833981Abstract: A spin valve magnetic head, providing on a substrate, a laminated structure that has an antiferromagnetic layer, fixation layer, non-magnetic layer and unconstraint layer, and having a first underlayer of Ta, a second underlayer of NiFeCr and a third underlayer of NiFe, which underlayers are interposed between the substrate and the laminated structure.Type: GrantFiled: February 22, 2002Date of Patent: December 21, 2004Assignee: Hitachi, Ltd.Inventors: Shigekazu Suwabe, Shin Noguchi, Yasunari Tajima, Satoshi Shigematsu
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Publication number: 20040190206Abstract: A magnetic domain control underlayer is formed below a magnetoresistive multi-layered film thereby bringing the magnetic domain control film into contact with both lateral end faces of a free layer and appropriate magnetic domain control can be attained in a state of minimizing a surplus bias magnetic field from the magnetic domain control film.Type: ApplicationFiled: September 30, 2003Publication date: September 30, 2004Applicant: Hitachi Global Storage Technologies Japan, Ltd.Inventors: Norihiro Ookawa, Shuichi Kojima, Koji Okazaki, Satoshi Shigematsu, Yasunari Tajima
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Patent number: 6690163Abstract: To provide a spin-valve magnetic head comprising a layered film having preferable magnetic properties in which an interface control film to reduce magnetostriction to almost zero is inserted. By suppressing or offsetting the influence of an interface layer which increases the magnetostriction of a soft magnetic free layer in a spin-valve magnetoresistive layered film and making the magnetic properties of the very thin soft magnetic free layer preferable, a stable magnetic head of high sensitivity which is not influenced by stress is obtained by the improvement in the magnetic properties of the very thin soft magnetic free layer.Type: GrantFiled: January 21, 2000Date of Patent: February 10, 2004Assignee: Hitachi, Ltd.Inventors: Hiroyuki Hoshiya, Katsuro Watanabe, Yasunari Tajima
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Publication number: 20030002228Abstract: A spin valve magnetic head which can offer high output and stable operation is proposed.Type: ApplicationFiled: February 22, 2002Publication date: January 2, 2003Inventors: Shigekazu Suwabe, Shin Noguchi, Yasunari Tajima, Satoshi Shigematsu
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Patent number: 6088196Abstract: A magnetoresistive head comprising a magnetoresistive film having electric resistance varying with a magnetic field, a pair of electrodes for causing a current to flow into the magnetoresistive film, and a soft magnetic film for applying a transverse biasing field to the magnetoresistive film, the soft magnetic film containing at least one material of iron, cobalt, and nickel, and at least one compound of zirconium oxide, aluminum oxide, hafnium oxide, titanium oxide, beryllium oxide, magnesium oxide, a rare earth oxygen compound, zirconium nitride, hafnium nitride, aluminum nitride, titanium nitride, beryllium nitride, magnesium nitride, silicon nitride, and a rare earth nitrogen compound. The electric resistance of the soft magnetic film is raised by adding a compound thereto and current diverted from the magnetoresistive film to the soft magnetic film decreases, so that the reproducing voltage of the magnetoresistive head rises.Type: GrantFiled: July 7, 1997Date of Patent: July 11, 2000Assignee: Hitachi, Ltd.Inventors: Shigeru Tadokoro, Katsuro Watanabe, Takao Imagawa, Yasunari Tajima
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Patent number: 5969910Abstract: A magnetic head having a magnetoresistive head having a spin valve structure in which a composite magnetic layer of a rotatable magnetizing direction layer and oxide or the like is used for a lower shielding layer and/or an upper shielding layer and a magnetic disk apparatus using such a head are disclosed. According to the invention, a magnetic head having a head of a magnetoresistance effect type generating a high output with low noises and a magnetic disk apparatus having a large quantity with high recording density can be realized.Type: GrantFiled: May 19, 1997Date of Patent: October 19, 1999Assignee: Hitachi, Ltd.Inventors: Takao Imagawa, Shigeru Tadokoro, Yasunari Tajima, Hiroshi Kamio