Patents by Inventor Yo Sato
Yo Sato 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: 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: 9311934Abstract: Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO and a current switching system electrically coupled to the STO. The current switching system can be used to optimize the STO frequency by changing the STO bias polarity, i.e., by changing the direction of the current flowing to the STO. As a result, the difference between the STO frequency and the magnetic media frequency is minimized, which improves recording capability of the MAMR head.Type: GrantFiled: July 24, 2015Date of Patent: April 12, 2016Assignee: HGST Netherlands B.V.Inventors: Masato Shiimoto, Masashige Sato, Masukazu Igarashi, Yo Sato, Masato Matsubara
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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
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Publication number: 20150228295Abstract: 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: ApplicationFiled: February 12, 2014Publication date: August 13, 2015Applicant: HGST Netherlands B.V.Inventors: Masato SHIIMOTO, Masukaza IGARASHI, Keiichi NAGASAKA, Yo SATO
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Patent number: 9099107Abstract: In one embodiment, a spin torque oscillator (STO) includes a reference layer having a magnetization that is capable of free in-plane rotation, a field generation layer (FGL) including at least one magnetic film having an easy magnetization plane effectively in a film plane, wherein a magnetization of the FGL is capable of in-plane rotation, and a stabilizing layer (STL) positioned on a side of the FGL opposite the reference layer, the STL including a magnetic film having an easy magnetization plane effectively in a film plane, wherein a magnetization of the STL is capable of in-plane rotation, wherein a product of a saturation magnetization of the STL multiplied by a thickness of the STL is less than half a product of a magnetization of the FGL multiplied by a thickness of the FGL.Type: GrantFiled: January 23, 2015Date of Patent: August 4, 2015Assignee: HGST Netherlands B.V.Inventors: Masukazu Igarashi, Keiichi Nagasaka, Susumu Okamura, Yo Sato, Masashige Sato, Masato Shimoto
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Patent number: 9030777Abstract: A spin torque oscillator generates a strong high-frequency magnetic field stably and has high reliability. A magnetic recording head includes a main magnetic pole and a spin torque oscillator. A magnetization control layer is antiferromagnetically coupled via a non-magnetic coupling layer with an interface contacting a high-frequency magnetic field generation layer of the spin torque oscillator.Type: GrantFiled: March 13, 2013Date of Patent: May 12, 2015Assignee: Hitachi, Ltd.Inventor: Yo Sato
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Publication number: 20150124347Abstract: 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: ApplicationFiled: November 1, 2013Publication date: May 7, 2015Applicant: HGST Netherlands B.V.Inventors: Masato Shimoto, Keiichi Nagasaka, Masato Matsubara, Yo Sato
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Patent number: 9007723Abstract: In one embodiment, a microwave-assisted magnetic recording (MAMR) head includes a main pole configured to write data to a magnetic medium using a write magnetic field, a write coil, wherein the write magnetic field is produced by the main pole upon a recording current, Iw, being provided to the write coil, and a spin torque oscillator (STO) positioned near the main pole, the STO being configured to provide a high-frequency assistance magnetic field to the magnetic medium upon a STO drive current, ISTO, being provided to the STO, wherein the STO drive current, ISTO, is ramped-up prior to the recording current, Iw, being provided to the write coil in order to begin a write operation for writing data to the magnetic medium. A method of operation for the MAMR head and an apparatus including the MAMR head are also described according to additional embodiments.Type: GrantFiled: December 13, 2013Date of Patent: April 14, 2015Assignee: HGST Netherlands B.V.Inventors: Masukazu Igarashi, Masato Shiimoto, Masato Matsubara, Yo Sato, Kenji Sugiura
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Patent number: 9007722Abstract: To uniformly determine the positional relationship between a main magnetic pole and a spin torque oscillator while independently optimizing the main magnetic pole and the spin torque oscillator. On a trailing end surface of a main magnetic pole, a step is provided at the boundary between the main magnetic pole and a gap material disposed on both sides thereof, and a spin torque oscillator is formed on the step. The spin torque oscillator is effectively separated into two regions by utilizing the step. Further, a part of the spin torque oscillator is removed so as to disable the unwanted region, thereby realizing a self-alignment type high frequency magnetic field assisted magnetic recording head structure such that the positions of the end portions of the main magnetic pole and the spin torque oscillator are aligned.Type: GrantFiled: August 16, 2013Date of Patent: April 14, 2015Assignee: Hitachi, Ltd.Inventors: Junichiro Shimizu, Kikuo Kusukawa, Yo Sato, Masukazu Igarashi
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Patent number: 9007721Abstract: A spin torque oscillator is provided which is adapted to high data transfer rates and which can perform assisted magnetic recording of sufficient magnitude. A spin torque oscillator is provided with a stacked spin injection layer and a high frequency magnetic field generation layer. The stacked spin injection layer has a stacked structure in which a first magnetic layer, a coupling layer, and a second magnetic layer are stacked in the order mentioned from a far side as viewed from the high frequency magnetic field generation layer. Magnetization of the first magnetic layer and magnetization of the second magnetic layer are coupled antiparallel to each other. A polarity of the magnetization of the second magnetic layer is reversed temporally earlier than a magnetic field polarity reversal of a leakage magnetic field from the main magnetic pole.Type: GrantFiled: August 2, 2013Date of Patent: April 14, 2015Assignee: Hitachi, Ltd.Inventors: Yo Sato, Katsuro Watanabe, Keizou Katou, Masukazu Igarashi
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Patent number: 8953282Abstract: In a Spin Torque Oscillator (STO) comprising an underlayer, a first magnetic layer disposed on the underlayer, a non-magnetic intermediate layer disposed on the first magnetic layer, and a second magnetic layer disposed on the non-magnetic intermediate layer, the non-magnetic intermediate layer is a non-magnetic alloy containing 50 at % or more of at least one kind of element selected from a first group consisting of Cu, Ag, and Au, and further at least 0.1 at % or more in total of at least one kind of element selected from a second group consisting of Cu, Ag, Au, Cr, Ti, Zr, Hf, V, Nb, Ta, Ru, Os, Pd, Pt, Rh, and Ir that does not overlap with the element from the first group.Type: GrantFiled: August 6, 2013Date of Patent: February 10, 2015Assignee: Hitachi, Ltd.Inventors: Yoshihiro Shiroishi, Katsuro Watanabe, Yo Sato
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Patent number: 8854768Abstract: To realize a highly reliable magnetic head for a high-frequency magnetic field assisted recording system by preventing current crowding in an oscillator and increasing the current resistance of the oscillator. Between a main pole that generates a recording magnetic field and a trailing shield, an oscillator that includes a non-magnetic metal layer, a spin injection pinned layer, an intermediate layer, and a high-frequency magnetic field generation layer and that generates a high-frequency magnetic field is disposed. The non-magnetic metal layer adjacent to the main pole is tapered with the width gradually increasing from the trailing side toward the leading side.Type: GrantFiled: January 29, 2014Date of Patent: October 7, 2014Assignee: Hitachi, Ltd.Inventors: Kenji Sugiura, Yo Sato, Masukazu Igarashi, Katsuro Watanabe
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Patent number: 8830627Abstract: In a magnetic head of a high-frequency magnetic field assisted recording system, a width of a high-frequency magnetic field from an oscillator is decreased to enhance an oscillation frequency, in order to realize a high-density recording. An oscillator provided near a main pole, which generates a recording magnetic field, for generating a high-frequency magnetic field is patterned by a conventional photolithography, and then, an oxidation, nitridation, or oxynitridation is performed on the side face in a track width direction. With this process, an oxide layer, a nitride layer, or an oxynitride layer, which is made of a material of the oscillator, is formed on the side face of the oscillator in the track width direction, and the shape of the oscillator is formed to be semi-circular.Type: GrantFiled: January 7, 2013Date of Patent: September 9, 2014Assignee: Hitachi, Ltd.Inventors: Kenji Sugiura, Katsuro Watanabe, Masukazu Igarashi, Yo Sato
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Patent number: 8824103Abstract: The strength of a magnetic field applied from a main pole to an oscillator and the strength of a magnetic field applied from the main pole to a recording medium are improved in a magnetic recording head for microwave assisted recording. In the magnetic recording head according to the present invention, an interval between the main pole and a trailing shield at a place in a position above an air bearing surface is larger than an interval between the main pole and the trailing shield on the air bearing surface.Type: GrantFiled: February 24, 2012Date of Patent: September 2, 2014Assignee: Hitachi, Ltd.Inventors: Masato Shiimoto, Kenji Sugiura, Mikito Sugiyama, Isao Nunokawa, Yo Sato, Katsuro Watanabe, Kazuhiko Hosomi, Nobuo Yoshida
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Publication number: 20140211340Abstract: To realize a highly reliable magnetic head for a high-frequency magnetic field assisted recording system by preventing current crowding in an oscillator and increasing the current resistance of the oscillator. Between a main pole that generates a recording magnetic field and a trailing shield, an oscillator that includes a non-magnetic metal layer, a spin injection pinned layer, an intermediate layer, and a high-frequency magnetic field generation layer and that generates a high-frequency magnetic field is disposed. The non-magnetic metal layer adjacent to the main pole is tapered with the width gradually increasing from the trailing side toward the leading side.Type: ApplicationFiled: January 29, 2014Publication date: July 31, 2014Applicant: HITACHI, LTD.Inventors: Kenji SUGIURA, Yo SATO, Masukazu IGARASHI, Katsuro WATANABE
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Patent number: 8778515Abstract: Embodiments of the present invention provide a practical magneto-resistive effect element for CPP-GMR, which exhibits appropriate resistance-area-product and high magnetoresistance change ratio, and meets the demand for a narrow read gap. Certain embodiments of a magneto-resistive effect element in accordance with the present invention include a pinned ferromagnetic layer containing a first ferromagnetic film having a magnetization direction fixed in one direction, a free ferromagnetic layer containing a second ferromagnetic film having a magnetization direction varying in response to an external magnetic field, an intermediate layer provided between the pinned ferromagnetic layer and the free ferromagnetic layer, and a current confinement layer for confining a current. At least one of the pinned ferromagnetic layer or the free ferromagnetic layer includes a highly spin polarized layer.Type: GrantFiled: November 21, 2008Date of Patent: July 15, 2014Assignee: HGST Netherlands B.V.Inventors: Yo Sato, Katsumi Hoshino, Hiroyuki Hoshiya