Patents by Inventor Keiichi Nagasaka
Keiichi Nagasaka 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: 20240274436Abstract: Provided are a film forming method in which oxygen defects are suppressed, and a substrate processing method. Provided is a film forming method having a step for cooling a substrate to a very-low-temperature state of 200 K or less, and a step for forming an oxide semiconductor film on the cooled substrate.Type: ApplicationFiled: June 2, 2022Publication date: August 15, 2024Inventors: Shota ISHIBASHI, Toru KITADA, Keiichi NAGASAKA
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Patent number: 10037772Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole, a seed layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO comprises a spin polarized layer (SPL), an interlayer with fcc structure, and a field generating layer (FGL), in this order in the stacking direction. The FGL comprises a low magnetic flux density interface (LMFDI) layer with bcc structure that directly contacts the interlayer.Type: GrantFiled: September 25, 2017Date of Patent: July 31, 2018Assignee: Western Digital Technologies, Inc.Inventors: Susumu Okamura, Masashige Sato, Keiichi Nagasaka, Yo Sato
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Patent number: 9990943Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole and a texture control layer (TCL), a seed control layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO has a crystallographic preferred growth orientation and includes a spin polarized layer (SPL). The TCL may include a Cu layer.Type: GrantFiled: August 1, 2017Date of Patent: June 5, 2018Assignee: Western Digital Technologies, Inc.Inventors: Susumu Okamura, Yo Sato, Keiichi Nagasaka, Masashige Sato
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Publication number: 20180025746Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole, a seed layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO comprises a spin polarized layer (SPL), an interlayer with fcc structure, and a field generating layer (FGL), in this order in the stacking direction. The FGL comprises a low magnetic flux density interface (LMFDI) layer with bcc structure that directly contacts the interlayer.Type: ApplicationFiled: September 25, 2017Publication date: January 25, 2018Inventors: Susumu Okamura, Masashige Sato, Keiichi Nagasaka, Yo Sato
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Publication number: 20180005651Abstract: A magnetic write head having a spin torque oscillator with a magnetic field sensor for accurately determining magnetic field oscillation frequency. The spin torque oscillator has one or more tunnel junction (TMR) sensors formed at the side of the spin torque oscillator. The TMR sensor advantageously detects a magnetic field signal that is an additive signal of both fields from the spin polarization layer and the magnetic field generation layer, thereby providing efficient detection of magnetic field and associated oscillation frequency.Type: ApplicationFiled: June 30, 2016Publication date: January 4, 2018Inventors: Masashige Sato, Susumu Okamura, Yo Sato, Keiichi Nagasaka
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Patent number: 9858952Abstract: A magnetic write head having a spin torque oscillator with a magnetic field sensor for accurately determining magnetic field oscillation frequency. The spin torque oscillator has one or more tunnel junction (TMR) sensors formed at the side of the spin torque oscillator. The TMR sensor advantageously detects a magnetic field signal that is an additive signal of both fields from the spin polarization layer and the magnetic field generation layer, thereby providing efficient detection of magnetic field and associated oscillation frequency.Type: GrantFiled: June 30, 2016Date of Patent: January 2, 2018Assignee: Western Digital Technologies, Inc.Inventors: Masashige Sato, Susumu Okamura, Yo Sato, Keiichi Nagasaka
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Publication number: 20170365282Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole and a texture control layer (TCL), a seed control layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO has a crystallographic preferred growth orientation and includes a spin polarized layer (SPL). The TCL may include a Cu layer.Type: ApplicationFiled: August 1, 2017Publication date: December 21, 2017Inventors: Susumu Okamura, Yo Sato, Keiichi Nagasaka, Masashige Sato
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Patent number: 9805746Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole, a seed layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO comprises a spin polarized layer (SPL), an interlayer with fcc structure, and a field generating layer (FGL), in this order in the stacking direction. The FGL comprises a low magnetic flux density interface (LMFDI) layer with bcc structure that directly contacts the interlayer.Type: GrantFiled: June 28, 2016Date of Patent: October 31, 2017Assignee: Western Digital Technologies, Inc.Inventors: Susumu Okamura, Masashige Sato, Keiichi Nagasaka, Yo Sato
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Patent number: 9728210Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole and a texture control layer (TCL), a seed control layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO has a crystallographic preferred growth orientation and includes a spin polarized layer (SPL). The TCL may include a Cu layer.Type: GrantFiled: November 25, 2015Date of Patent: August 8, 2017Assignee: Western Digital Technologies, Inc.Inventors: Susumu Okamura, Yo Sato, Keiichi Nagasaka, Masashige Sato
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Publication number: 20170148474Abstract: A magnetic field-assisted magnetic recording (MAMR) head is provided, which includes a recording main pole and a texture control layer (TCL), a seed control layer, and a spin torque oscillator (STO) positioned over the main pole, in this order, in a stacking direction from a leading side to a trailing side of the recording head. The STO has a crystallographic preferred growth orientation and includes a spin polarized layer (SPL). The TCL may include a Cu layer.Type: ApplicationFiled: November 25, 2015Publication date: May 25, 2017Inventors: Susumu Okamura, Yo Sato, Keiichi Nagasaka, Masashige Sato
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Patent number: 9437222Abstract: A magnetic oscillator for use in Microwave Assisted Magnetic Recording (MAMR). The magnetic oscillator can be a spin torque oscillator and includes a magnetic spin polarization layer, a magnetic field generation layer and a non-magnetic intermediate layer sandwiched between the magnetic spin polarization layer and the magnetic field generation layer. The non-magnetic intermediate layer is constructed of a material that provides improved performance, increased lifespan and thermal robustness. The magnetic intermediate layer is constructed of an alloy of Ag and an element X. More preferably the element X can be Sn or Zn.Type: GrantFiled: May 30, 2015Date of Patent: September 6, 2016Assignee: HGST Netherlands B.V.Inventors: Susumu Okamura, Masao Shiimoto, Katsuro Watanabe, Masashige Sato, Keiichi Nagasaka, Yo Sato, Masukazu Igarashi
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Patent number: 9406315Abstract: The embodiments disclosed generally relate to an STO structure for a magnetic head. The STO structure has an FGL having a greater thickness than the SPL. The SPL may have multiple layers. In one embodiment, a MAMR head comprises a main pole; a trailing shield; and an STO coupled between the main pole and the trailing shield. The STO includes: a first magnetic layer having a first thickness; a non-magnetic spacer layer coupled to the first magnetic layer; and a second magnetic layer having a second thickness and coupled to the non-magnetic spacer layer, wherein the first thickness is greater than the second thickness, wherein a current is charged from the first magnetic layer to the second magnetic layer, and wherein a vertical magnetic anisotropy field of the second magnetic film is less than 0 kOe.Type: GrantFiled: February 12, 2014Date of Patent: August 2, 2016Assignee: HGST Netherlands B.V.Inventors: Masato Shiimoto, Masukaza Igarashi, Keiichi Nagasaka, Yo Sato
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Patent number: 9378759Abstract: Embodiments disclosed herein generally relate to a magnetic disk device employing a MAMR head. The MAMR head includes an STO. The STO comprises an underlayer, an SPL, an interlayer, an FGL, and a capping layer. The SPL is comprised of a high perpendicular magnetic anisotropy material. The SPL has a large effective perpendicular magnetic anisotropy field, and the SPL has a lower magnetic moment than the FGL. An applied current is adapted to flow in a direction from the FGL to the SPL resulting in the magnetization direction of the SPL being almost perpendicular to the FGL and anti-parallel to a head-gap magnetic field due to a relation between a first spin torque directed from the SPL to the FGL and a second spin torque directed from the FGL to the SPL.Type: GrantFiled: November 20, 2014Date of Patent: June 28, 2016Assignee: HGST NETHERLANDS B.V.Inventors: Keiichi Nagasaka, Yo Sato, Masashige Sato, Susumu Okamura, Masato Shiimoto, Masukazu Igarashi
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Publication number: 20160148627Abstract: Embodiments disclosed herein generally relate to a magnetic disk device employing a MAMR head. The MAMR head includes an STO. The STO comprises an underlayer, an SPL, an interlayer, an FGL, and a capping layer. The SPL is comprised of a high perpendicular magnetic anisotropy material. The SPL has a large effective perpendicular magnetic anisotropy field, and the SPL has a lower magnetic moment than the FGL. An applied current is adapted to flow in a direction from the FGL to the SPL resulting in the magnetization direction of the SPL being almost perpendicular to the FGL and anti-parallel to a head-gap magnetic field due to a relation between a first spin torque directed from the SPL to the FGL and a second spin torque directed from the FGL to the SPL.Type: ApplicationFiled: November 20, 2014Publication date: May 26, 2016Inventors: Keiichi NAGASAKA, Yo SATO, Masashige SATO, Susumu OKAMURA, Masato SHIIMOTO, Masukazu IGARASHI
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Patent number: 9336797Abstract: The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.Type: GrantFiled: May 29, 2014Date of Patent: May 10, 2016Assignee: HGST NETHERLANDS B.V.Inventors: Masukazu Igarashi, Masato Matsubara, Keiichi Nagasaka, Yo Sato, Masato Shiimoto, Masashige Sato
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Patent number: 9305574Abstract: Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO. The STO has a first magnetic layer, a second magnetic layer and an interlayer disposed between the first and second magnetic layers. One of the first and second magnetic layers is made of a negative polarization material while the other magnetic layer is made of a positive polarization material. As a result, the magnetizations in the first and second magnetic layers are in the same direction when in oscillation, which suppresses the partial cancellation of the magnetizations in the first and second magnetic layers and strengthens the AC magnetic field.Type: GrantFiled: September 23, 2014Date of Patent: April 5, 2016Assignee: HGST Netherlands B.V.Inventors: Keiichi Nagasaka, Yo Sato, Masato Shiimoto, Masashige Sato, Masukazu Igarashi, Susumu Okamura
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Publication number: 20160086623Abstract: Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO. The STO has a first magnetic layer, a second magnetic layer and an interlayer disposed between the first and second magnetic layers. One of the first and second magnetic layers is made of a negative polarization material while the other magnetic layer is made of a positive polarization material. As a result, the magnetizations in the first and second magnetic layers are in the same direction when in oscillation, which suppresses the partial cancellation of the magnetizations in the first and second magnetic layers and strengthens the AC magnetic field.Type: ApplicationFiled: September 23, 2014Publication date: March 24, 2016Inventors: Keiichi NAGASAKA, Yo SATO, Masato SHIIMOTO, Masashige SATO, Masukazu IGARASHI, Susumu OKAMURA
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Patent number: 9230569Abstract: In one embodiment, a magnetic head includes a main magnetic pole positioned configured to generate a writing magnetic field when current is applied to a write coil, and a spin torque oscillator (STO) located adjacent the main magnetic pole, the STO being configured to generate a high frequency magnetic field when current is applied thereto, wherein the high frequency magnetic field is generated simultaneously to the writing magnetic field to assist in reversing magnetization of a magnetic recording medium. The STO includes: a spin polarization layer (SPL), a field generation layer (FGL) positioned adjacent the SPL, and one or more interlayers positioned between the SPL and the FGL, and a magnetization easy axis of the SPL is positioned in an in-plane direction such that the SPL has no perpendicular magnetic anisotropy.Type: GrantFiled: November 26, 2014Date of Patent: January 5, 2016Assignee: HGST Netherlands B.V.Inventors: Masato Shimoto, Masukazu Igarashi, Keiichi Nagasaka, Yo Sato, Susumu Okamura, Masashige Sato
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Patent number: 9230597Abstract: In one embodiment, a magnetic head includes a main pole configured to write data to a magnetic medium, a trailing shield positioned on a trailing side of the main pole, and a STO between the main pole and the trailing shield, wherein the STO includes a laminated structure having a FGL, a spun polarization layer (SPL), and a non-magnetic spacer positioned between the FGL and the SPL, wherein the FGL includes a laminated structure having one or more layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer. In another embodiment, a method is presented for forming such a magnetic head utilizing a FGL that includes a laminated structure baying layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer.Type: GrantFiled: November 1, 2013Date of Patent: January 5, 2016Assignee: HGST Netherlands B.V.Inventors: Masato Shimoto, Keiichi Nagasaka, Masato Matsubara, Yo Sato
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Publication number: 20150348574Abstract: The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.Type: ApplicationFiled: May 29, 2014Publication date: December 3, 2015Applicant: HGST NETHERLANDS B.V.Inventors: Masukazu IGARASHI, Masato MATSUBARA, Keiichi NAGASAKA, Yo SATO, Masato SHIIMOTO, Masashige SATO