Patents by Inventor Sangmun Oh

Sangmun Oh 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).

  • Publication number: 20250246203
    Abstract: The present embodiments relate to a tunnel magnetoresistance (TMR) element. The TMR element can include a free layer comprising a metallic alloy that is doped using a dopant element. In some instances, the metallic alloy comprises a cobalt-iron (CoFe) alloy. The present embodiments relate to doping a small amount of an element (e.g., hafnium (Hf), tantalum (Ta), Yttrium (Y)) in a high flux CoFe layer of a tunnel magnetoresistance (TMR) element. The small amount of dopant can suppress a long-range order in the CoFe film. The amorphous state of a CoFe alloy can be induced by the dopant and result in a magnetically soft layer. A resistance of the TMR element can be modified based on an application of an external magnetic field to the free layer and the pin layer.
    Type: Application
    Filed: March 11, 2025
    Publication date: July 31, 2025
    Inventors: Hui-Chuan Wang, Shohei Kawasaki, Kunliang Zhang, Sangmun Oh, Zheng Gao
  • Patent number: 12266384
    Abstract: The present embodiments relate to a tunnel magnetoresistance (TMR) element. The TMR element can include a free layer comprising a metallic alloy that is doped using a dopant element. In some instances, the metallic alloy comprises a cobalt-iron (CoFe) alloy. The present embodiments relate to doping a small amount of an element (e.g., hafnium (Hf), tantalum (Ta), Yttrium (Y)) in a high flux CoFe layer of a tunnel magnetoresistance (TMR) element. The small amount of dopant can suppress a long-range order in the CoFe film. The amorphous state of a CoFe alloy can be induced by the dopant and result in a magnetically soft layer. A resistance of the TMR element can be modified based on an application of an external magnetic field to the free layer and the pin layer.
    Type: Grant
    Filed: January 5, 2023
    Date of Patent: April 1, 2025
    Assignee: Headway Technologies, Inc.
    Inventors: Hui-Chuan Wang, Shohei Kawasaki, Kunliang Zhang, Sangmun Oh, Zheng Gao
  • Publication number: 20240233999
    Abstract: The present embodiments relate to a tunnel magnetoresistance (TMR) element. The TMR element can include a free layer comprising a metallic alloy that is doped using a dopant element. In some instances, the metallic alloy comprises a cobalt-iron (CoFe) alloy. The present embodiments relate to doping a small amount of an element (e.g., hafnium (Hf), tantalum (Ta), Yttrium (Y)) in a high flux CoFe layer of a tunnel magnetoresistance (TMR) element. The small amount of dopant can suppress a long-range order in the CoFe film. The amorphous state of a CoFe alloy can be induced by the dopant and result in a magnetically soft layer. A resistance of the TMR element can be modified based on an application of an external magnetic field to the free layer and the pin layer.
    Type: Application
    Filed: January 5, 2023
    Publication date: July 11, 2024
    Inventors: Hui-Chuan Wang, Shohei Kawasaki, Kunliang Zhang, Sangmun Oh, Zheng Gao
  • Patent number: 11646052
    Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head, one or more separate polarizer layers, or combinations thereof. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes a Mn or a Mn-alloy layer.
    Type: Grant
    Filed: April 12, 2021
    Date of Patent: May 9, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: James Mac Freitag, Zheng Gao, Masahiko Hashimoto, Sangmun Oh
  • Publication number: 20210233560
    Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head, one or more separate polarizer layers, or combinations thereof. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes a Mn or a Mn-alloy layer.
    Type: Application
    Filed: April 12, 2021
    Publication date: July 29, 2021
    Applicant: Western Digital Technologies, Inc.
    Inventors: James Mac FREITAG, Zheng GAO, Masahiko HASHIMOTO, Sangmun OH
  • Patent number: 10997993
    Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head, one or more separate polarizer layers, or combinations thereof. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes a Mn or a Mn-alloy layer.
    Type: Grant
    Filed: February 14, 2020
    Date of Patent: May 4, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: James Mac Freitag, Zheng Gao, Masahiko Hashimoto, Sangmun Oh
  • Patent number: 10867625
    Abstract: A spin transfer torque (STT) device has a free ferromagnetic layer that includes a Heusler alloy layer and a template layer beneath and in contact with the Heusler alloy layer. The template layer may be a ferromagnetic alloy comprising one or more of Co, Ni and Fe and the element X, where X is selected from one or more of Ta, B, Hf, Zr, W, Nb and Mo. A CoFe nanolayer may be formed below and in contact with the template layer. The STT device may be a spin-torque oscillator (STO), like a STO incorporated into the write head of a magnetic recording disk drive. The STT device may also be a STT in-plane or perpendicular magnetic tunnel junction (MTJ) cell for magnetic random access memory (MRAM). The template layer reduces the critical current density of the STT device.
    Type: Grant
    Filed: February 27, 2020
    Date of Patent: December 15, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC
    Inventors: James Mac Freitag, Zheng Gao, Masahiko Hashimoto, Sangmun Oh, Hua Ai Zeng
  • Patent number: 10566015
    Abstract: A spin transfer torque (STT) device has a free ferromagnetic layer that includes a Heusler alloy layer and a template layer beneath and in contact with the Heusler alloy layer. The template layer may be a ferromagnetic alloy comprising one or more of Co, Ni and Fe and the element X, where X is selected from one or, more of Ta, B, Hf, Zr, W, Nb and Mo. A CoFe nanolayer may be formed below and in contact with the template layer. The STT device may be a spin-torque oscillator (STO), like a STO incorporated into the write head of a magnetic recording disk drive. The STT device may also be a STT in-plane or perpendicular magnetic tunnel junction (MTJ) cell for magnetic random access memory (MRAM). The template layer reduces the critical current density of the STT device.
    Type: Grant
    Filed: May 10, 2018
    Date of Patent: February 18, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: James Mac Freitag, Zheng Gao, Masahiko Hashimoto, Sangmun Oh, Hua Al Zeng
  • Patent number: 10460752
    Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head or a separate polarizer layer. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes Mn or a Mn-alloy layer between one or more metal or metal alloy films.
    Type: Grant
    Filed: May 10, 2018
    Date of Patent: October 29, 2019
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: James Mac Freitag, Zheng Gao, Masahiko Hashimoto, Sangmun Oh
  • Publication number: 20190279668
    Abstract: A magnetic recording write head and system has a spin-torque oscillator (STO) located between the write head's write pole and trailing shield. The STO's ferromagnetic free layer is located near the write pole with a multilayer seed layer between the write pole and the free layer. The STO's nonmagnetic spacer layer is between the free layer and the STO's ferromagnetic polarizer. The polarizer may be the trailing shield of the write head or a separate polarizer layer. The STO electrical circuitry causes electron flow from the write pole to the trailing shield. The multilayer seed layer removes the spin polarization of electrons from the write pole, which enables electrons reflected from the polarizer layer to become spin polarized, which creates the spin transfer torque on the magnetization of the free layer. The multilayer seed layer includes Mn or a Mn-alloy layer between one or more metal or metal alloy films.
    Type: Application
    Filed: May 10, 2018
    Publication date: September 12, 2019
    Inventors: James Mac FREITAG, Zheng GAO, Masahiko HASHIMOTO, Sangmun OH
  • Publication number: 20190279667
    Abstract: A spin transfer torque (STT) device has a free ferromagnetic layer that includes a Heusler alloy layer and a template layer beneath and in contact with the Heusler alloy layer. The template layer may be a ferromagnetic alloy comprising one or more of Co, Ni and Fe and the element X, where X is selected from one or more of Ta, B, Hf, Zr, W, Nb and Mo. A CoFe nanolayer may be formed below and in contact with the template layer. The STT device may be a spin-torque oscillator (STO), like a STO incorporated into the write head of a magnetic recording disk drive. The STT device may also be a STT in-plane or perpendicular magnetic tunnel junction (MTJ) cell for magnetic random access memory (MRAM). The template layer reduces the critical current density of the STT device.
    Type: Application
    Filed: May 10, 2018
    Publication date: September 12, 2019
    Applicant: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: JAMES MAC FREITAG, ZHENG GAO, MASAHIKO HASHIMOTO, SANGMUN OH, HUA AI ZENG
  • Patent number: 9940955
    Abstract: A read head is provided with a scissors sensor. The read head may include a bottom magnetic shield, and a first non-magnetic seed layer, a magnetic seed layer, a second non-magnetic seed layer, an antiferromagnetic layer, a coupling layer, a first free magnetic layer, a spacer layer, and a second free magnetic layer positioned above the bottom magnetic shield, in this order. A pair of magnetic side shield layers may be positioned on respective sides of the second free magnetic layer.
    Type: Grant
    Filed: December 1, 2015
    Date of Patent: April 10, 2018
    Assignee: Western Digital Technologies, Inc.
    Inventors: Kouichi Nishioka, Zheng Gao, Ching Tsang, Quang Le, Sangmun Oh
  • Publication number: 20170154643
    Abstract: A read head is provided with a scissors sensor. The read head may include a bottom magnetic shield, and a first non-magnetic seed layer, a magnetic seed layer, a second non-magnetic seed layer, an antiferromagnetic layer, a coupling layer, a first free magnetic layer, a spacer layer, and a second free magnetic layer positioned above the bottom magnetic shield, in this order. A pair of magnetic side shield layers may be positioned on respective sides of the second free magnetic layer.
    Type: Application
    Filed: December 1, 2015
    Publication date: June 1, 2017
    Inventors: Kouichi Nishioka, Zheng Gao, Ching Tsang, Quang Le, Sangmun Oh
  • Patent number: 9337415
    Abstract: A magnetic tunnel junction (MTJ) for use in a magnetoresistive random access memory (MRAM) has a CoFeB alloy free layer located between the MgO tunnel barrier layer and an upper MgO capping layer, and a CoFeB alloy enhancement layer between the MgO capping layer and a Ta cap. The CoFeB alloy free layer has high Fe content to induce perpendicular magnetic anisotropy (PMA) at the interfaces with the MgO layers. To avoid creating unnecessary PMA in the enhancement layer due to its interface with the MgO capping layer, the enhancement layer has low Fe content. After all of the layers have been deposited on the substrate, the structure is annealed to crystallize the MgO. The CoFeB alloy enhancement layer inhibits diffusion of Ta from the Ta cap layer into the MgO capping layer and creates good crystallinity of the MgO by providing CoFeB at the MgO interface.
    Type: Grant
    Filed: March 20, 2015
    Date of Patent: May 10, 2016
    Assignee: HGST Netherlands B.V.
    Inventors: Sangmun Oh, Zheng Gao, Kochan Ju
  • Patent number: 9214168
    Abstract: A method and system for providing a magnetic transducer is described. The method and system include providing a magnetic structural barrier layer and a crystalline magnetic layer on the magnetic structural barrier layer. The magnetic structural barrier layer may reside on a shield. The method and system also include providing a nonmagnetic layer on the crystalline magnetic layer. A pinning layer is provided on the nonmagnetic layer. Similarly, a pinned layer is provided on the pinning layer. The pinning layer is magnetically coupled with the pinned layer. The method and system also include providing a free layer and a nonmagnetic spacer layer between the pinned layer and the free layer.
    Type: Grant
    Filed: August 28, 2013
    Date of Patent: December 15, 2015
    Assignee: Western Digital (Fremont), LLC
    Inventors: Chando Park, Qunwen Leng, Sangmun Oh, Mahendra Pakala
  • Patent number: 9177573
    Abstract: A tunneling magnetoresistance (TMR) device has a thin MgO tunneling barrier layer and a free ferromagnetic multilayer. The free ferromagnetic multilayer includes a CoFeB first ferromagnetic layer, a face-centered-cubic (fcc) NiFe compensation layer with negative magnetostriction, and a body-centered-cubic (bcc) NiFe insertion layer between the CoFeB layer and the fcc NiFe compensation layer. An optional ferromagnetic nanolayer may be located between the MgO barrier layer and the CoFeB layer. An optional amorphous separation layer may be located between the CoFeB layer and the bcc NiFe insertion layer. The bcc NiFe insertion layer (and the optional amorphous separation layer if it is used) prevents the fcc NiFe layer from adversely affecting the crystalline formation of the MgO and CoFeB layers during annealing. The bcc NiFe insertion layer also increases the TMR and lowers the Gilbert damping constant of the free ferromagnetic multilayer.
    Type: Grant
    Filed: April 30, 2015
    Date of Patent: November 3, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Sangmun Oh, Zheng Gao
  • Patent number: 9177575
    Abstract: A tunneling magnetoresistive (TMR) read head has a read gap with a reduced thickness. A multilayer seed layer includes a first ferromagnetic seed layer on the lower shield, a ferromagnetic NiFe alloy on the first seed layer, and a third seed layer of Ru or Pt on the NiFe seed layer. The first and NiFe seed layers are magnetically part of the lower shield, thereby effectively reducing the read gap thickness. A free layer/capping layer structure includes a multilayer ferromagnetic free layer and a Hf capping layer on the free layer. The free layer includes a B-containing upper layer in contact with the Hf capping layer prior to annealing. When the sensor is annealed Hf diffuses into the B-containing upper layer, forming an interface layer. The Hf-containing interface layer possesses negative magnetostriction, so the free layer is not required to contain NiFe.
    Type: Grant
    Filed: December 5, 2014
    Date of Patent: November 3, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Zheng Gao, Sangmun Oh, Susumu Okamura
  • Publication number: 20150062759
    Abstract: Embodiments of the present invention generally relate to a magnetic head having a sensor structure comprising a pinned layer, a spacer layer, a free layer and a capping structure. The free layer has a topmost layer comprising CoB and the capping structure comprises an X layer, where X is an element such as Hf, Zr, Ti, V, Nb, or Ta.
    Type: Application
    Filed: August 28, 2013
    Publication date: March 5, 2015
    Inventors: Chando PARK, Zheng GAO, Sangmun OH, Susumu OKAMURA, James Mac FREITAG
  • Patent number: 8958180
    Abstract: Embodiments of the present invention generally relate to a magnetic head having a sensor structure comprising a pinned layer, a spacer layer, a free layer and a capping structure. The free layer has a topmost layer comprising CoB and the capping structure comprises an X layer, where X is an element such as Hf, Zr, Ti, V, Nb, or Ta.
    Type: Grant
    Filed: August 28, 2013
    Date of Patent: February 17, 2015
    Assignee: HGST Netherlands, B.V.
    Inventors: Chando Park, Zheng Gao, Sangmun Oh, Susumu Okamura, James Mac Freitag
  • Publication number: 20140355152
    Abstract: In one embodiment, a magnetic head includes a reference layer having magnetic orientation about aligned with a plane of deposition thereof; a first free layer having a magnetic orientation out of a plane of deposition thereof; a spacer layer between the reference layer and the first free layer; a second free layer having a magnetic orientation out of a plane of deposition thereof; and an inserting layer between the first and second free layers.
    Type: Application
    Filed: May 29, 2013
    Publication date: December 4, 2014
    Applicant: HGST Netherlands B.V.
    Inventors: Chando Park, James M. Freitag, Sangmun Oh, Zheng Gao