Patents by Inventor Kuok San Ho

Kuok San Ho 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).

  • Magnetic recording write head with write pole having a tapered trailing end section with negative magnetic anisotropy
    Patent number: 10762919
    Abstract: A perpendicular magnetic recording write head includes a main portion formed of conventional high-moment magnetic materials, and a beveled or tapered trailing portion formed of a Co/Fe multilayer with negative magnetic anisotropy (negative anisotropy constant or —Ku). The Co/Fe multilayer tapered trailing portion has a high saturation magnetization (Ms) and thus functions as part of the write pole to direct the flux perpendicularly to the recording layer. Also, the —Ku Co/Fe multilayer tapered trailing portion has its hard axis oriented substantially orthogonal to the layer thickness and thus substantially prevents flux leakage into the write gap. The —Ku Co/Fe multilayer may also be formed on the sides of the write pole in the cross-track direction to prevent flux leakage into the side gaps.
    Type: Grant
    Filed: January 30, 2018
    Date of Patent: September 1, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Suping Song, Zhanjie Li, Yaguang Wei, Terence Tin-Lok Lam, Kuok San Ho
  • MAMR writer with low resistance MAMR stack
    Patent number: 10741202
    Abstract: The present disclosure generally relates to a magnetic media drive employing a magnetic recording head. The head includes a main pole at a media facing surface (MFS), a trailing shield at the MFS, and a MAMR stack disposed between the main pole and the trailing shield at the MFS. The MAMR stack includes a seed layer and at least one magnetic layer. The seed layer is fabricated from a thermally conductive material having electrical resistivity lower than that of the main pole. The seed layer has a stripe height greater than a stripe height of the at least one magnetic layer. With the extended seed layer, the bias current from the trailing shield to the main pole spreads further away from the MFS along the extended seed layer before flowing into the main pole, reducing temperature rise at or near the MAMR stack, leading to improved write head reliability.
    Type: Grant
    Filed: February 14, 2019
    Date of Patent: August 11, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Michael Kuok San Ho, Yunfei Ding, Zhigang Bai, Yaguang Wei, Terence Lam, Goncalo Baiao de Albuquerque, Xinjiang Shen, Feng Q. Liu
  • Areal density capability improvement with a main pole skin
    Patent number: 10734014
    Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole at a media facing surface (MFS), a trailing shield at the MFS, and a heavy metal layer disposed between the main pole and the trailing shield at the MFS. Spin-orbit torque (SOT) is generated from the heavy metal layer and transferred to a surface of the main pole as a current passes through the heavy metal layer in a cross-track direction. The SOT executes a torque on the surface magnetization of the main pole, which reduces the magnetic flux shunting from the main pole to the trailing shield. With the reduced magnetic flux shunting from the main pole to the trailing shield, write-ability is improved.
    Type: Grant
    Filed: June 14, 2018
    Date of Patent: August 4, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Suping Song, Zhanjie Li, Michael Kuok San Ho, Quang Le, Alexander M. Zeltser
  • Magnetic recording write head having YIG-heavy metal-YIG in write gap and side gap to maximize spin-orbit-coupling efficiency
    Patent number: 10734015
    Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole at a media facing surface (MFS), a trailing shield at the MFS, a heavy metal layer disposed between the main pole and the trailing shield at the MFS, and a yttrium-iron garnet (YIG) layer. Spin-orbit torque (SOT) is generated from the heavy metal layer and transferred to a surface of the main pole as a current passes through the heavy metal layer in a cross-track direction. The YIG layer is an electrical insulator, but also a good spin current conductor. Thus the charge current can be fully utilized for spin current conversion. The YIG layer does not dissipate energy because there is no shunting. With the reduced shunting from the main pole to the trailing shield, write-ability is improved.
    Type: Grant
    Filed: February 18, 2019
    Date of Patent: August 4, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Suping Song, Zhanjie Li, Michael Kuok San Ho
  • HIGH-BANDWIDTH STO BIAS ARCHITECTURE WITH INTEGRATED SLIDER VOLTAGE POTENTIAL CONTROL
    Publication number: 20200211584
    Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.
    Type: Application
    Filed: March 11, 2020
    Publication date: July 2, 2020
    Applicant: Western Digital Technologies, Inc.
    Inventors: John CONTRERAS, Yunfei DING, Kuok San HO, Ian Robson MCFADYEN, Joey Martin POSS
  • Magnetic recording write head with selected write gap current direction for minimization of cross-track interference
    Patent number: 10699734
    Abstract: A magnetic recording write head has an electrically-conductive structure in the write gap between the write pole and the trailing shield and electrical circuitry for directing current through the write gap. The current through the electrically-conductive structure generates a circular Ampere field which, at the disk-facing end of the write pole, is substantially parallel to the disk-facing end of the write pole. The electrically-conductive structure in the write gap may be a STO or an electrically-conductive layer that is not part of a STO. The current direction through the electrically-conductive structure in the write gap is selected so that the generated Ampere field at the write pole end is in substantially the same direction as the magnetization direction of the write head side shields, which has been discovered to result in minimization of cross-track interference.
    Type: Grant
    Filed: February 15, 2019
    Date of Patent: June 30, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Zhigang Bai, Alexander Taratorin, Anna Zheng, Venkatesh Chembrolu, Supradeep Narayana, Suping Song, Yaguang Wei, Terence Lam, Michael Kuok San Ho, Changqing Shi, Lijie Guan
  • Current-assisted magnetic recording write head with improved write gap structure
    Patent number: 10679650
    Abstract: A current-assisted magnetic recording write head has an electrically conductive layer in the write gap between the write pole and the trailing shield. Electrical circuitry directs current from the write pole, through the conductive layer, to the trailing shield. The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetization in the write pole to assist magnetization switching of the write pole. The write head's magnetic throat height (THm) is substantially the thickness of the trailing shield at the write gap, while the write head's electrical throat height (THe) is substantially the height of the conductive layer in the write gap. In embodiments of this invention, the signal-to-noise ratio (SNR) of the readback signal and the soft error rate (SER) of the recorded data can be improved with a write gap structure wherein THe is greater than THm.
    Type: Grant
    Filed: February 15, 2019
    Date of Patent: June 9, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Zhigang Bai, Venkatesh Chembrolu, Yaguang Wei, Terence Lam, Michael Kuok San Ho, Lijie Guan, Suping Song, Supradeep Narayana
  • GIANT SPIN-SEEBECK EFFECT INDUCED MAGNON TRANSFER TORQUE-ASSISTED MAMR
    Publication number: 20200176022
    Abstract: A magnetic recording device includes a main pole, a coil around the main pole, a trailing shield, and a spin torque oscillation device between the main pole and the trailing shield. The spin torque oscillation device includes one or more first layers, a spacer layer, and a field generation layer. The one or more first layers are over the main pole. The one or more first layers have a first heat conductance or include a low-heat-conductance material. The spacer layer is over the one or more first layers. The field generation layer is over the spacer layer. A heat sink is in contact with the trailing shield. The heat sink has a second heat conductance or includes a high-heat-conductance material. The second heat conductance of the heat sink is higher than the first heat conductance of the one or more first layers.
    Type: Application
    Filed: June 25, 2019
    Publication date: June 4, 2020
    Inventors: Zhanjie LI, Suping SONG, Michael Kuok San HO
  • Spin-orbit torque induced magnetization switching in a magnetic recording head
    Patent number: 10650847
    Abstract: The present disclosure generally relates to magnetic media devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The recording head includes a main pole, a trailing shield hot seed layer, a spin Hall layer disposed between the main pole and the trailing shield hot seed layer, and a spin-torque layer disposed between the main pole and the trailing shield hot seed layer. Spin-orbit torque (SOT) is generated from the spin Hall layer. The spin-torque layer magnetization switching or precession is induced by the SOT. The SOT based head reduces the switching current and the Vjump due to higher spin polarization ratio, which improves energy efficiency. In addition, the spin Hall layer and the spin-torque layer are easier to form compared to the conventional pseudo spin-valve structure.
    Type: Grant
    Filed: September 4, 2019
    Date of Patent: May 12, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Zhanjie Li, Suping Song, Kuok San Ho
  • Apparatus and method for writing to magnetic media using an AC bias current to enhance the write field
    Patent number: 10643642
    Abstract: An apparatus comprises a main pole, a trailing shield, a write-field-enhancing structure, a write coil, a write current control circuit configured to supply a write current to the write coil to record a bit to a magnetic medium, and a driving current control circuit configured to supply a driving current to the write-field-enhancing structure, wherein the driving current comprises a driving pulse, and wherein the driving current comprises an AC component with a duty cycle selected based at least in part on a power constraint. A method of writing to a magnetic medium comprises supplying a write current to a write coil of a magnetic write head, and supplying a driving current to a free layer disposed in a write gap between a main pole and a trailing shield, wherein the driving current comprises an AC component with a duty cycle based at least in part on a power constraint.
    Type: Grant
    Filed: July 1, 2019
    Date of Patent: May 5, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Gonçalo Marcos Baião De Albuquerque, Yunfei Ding, Alexander Goncharov, Kuok San Ho, Daniele Mauri, Goran Mihajlovic, Suping Song, Petrus Antonius Van Der Heijden
  • High-bandwidth STO bias architecture with integrated slider voltage potential control
    Patent number: 10629229
    Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.
    Type: Grant
    Filed: August 11, 2019
    Date of Patent: April 21, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: John Contreras, Yunfei Ding, Kuok San Ho, Ian Robson McFadyen, Joey Martin Poss
  • CURRENT-ASSISTED MAGNETIC RECORDING WRITE HEAD WITH IMPROVED WRITE GAP STRUCTURE
    Publication number: 20200005815
    Abstract: A current-assisted magnetic recording write head has an electrically conductive layer in the write gap between the write pole and the trailing shield. Electrical circuitry directs current from the write pole, through the conductive layer, to the trailing shield. The current through the conductive layer generates an Ampere field substantially orthogonal to the magnetization in the write pole to assist magnetization switching of the write pole. The write head's magnetic throat height (THm) is substantially the thickness of the trailing shield at the write gap, while the write head's electrical throat height (THe) is substantially the height of the conductive layer in the write gap. In embodiments of this invention, the signal-to-noise ratio (SNR) of the readback signal and the soft error rate (SER) of the recorded data can be improved with a write gap structure wherein THe is greater than THm.
    Type: Application
    Filed: February 15, 2019
    Publication date: January 2, 2020
    Inventors: Zhigang BAI, Venkatesh CHEMBROLU, Yaguang WEI, Terence LAM, Michael Kuok San HO, Lijie GUAN, Suping SONG, Supradeep NARAYANA
  • SPIN-ORBIT TORQUE INDUCED MAGNETIZATION SWITCHING IN A MAGNETIC RECORDING HEAD
    Publication number: 20190392861
    Abstract: The present disclosure generally relates to magnetic media devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The recording head includes a main pole, a trailing shield hot seed layer, a spin Hall layer disposed between the main pole and the trailing shield hot seed layer, and a spin-torque layer disposed between the main pole and the trailing shield hot seed layer. Spin-orbit torque (SOT) is generated from the spin Hall layer. The spin-torque layer magnetization switching or precession is induced by the SOT. The SOT based head reduces the switching current and the Vjump due to higher spin polarization ratio, which improves energy efficiency. In addition, the spin Hall layer and the spin-torque layer are easier to form compared to the conventional pseudo spin-valve structure.
    Type: Application
    Filed: September 4, 2019
    Publication date: December 26, 2019
    Inventors: Zhanjie LI, Suping SONG, Kuok San HO
  • HIGH-BANDWIDTH STO BIAS ARCHITECTURE WITH INTEGRATED SLIDER VOLTAGE POTENTIAL CONTROL
    Publication number: 20190362744
    Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.
    Type: Application
    Filed: August 11, 2019
    Publication date: November 28, 2019
    Applicant: Western Digital Technologies, Inc.
    Inventors: John CONTRERAS, Yunfei DING, Kuok San HO, Ian Robson MCFADYEN, Joey Martin POSS
  • APPARATUS AND METHOD FOR WRITING TO MAGNETIC MEDIA USING AN AC BIAS CURRENT TO ENHANCE THE WRITE FIELD
    Publication number: 20190325902
    Abstract: An apparatus comprises a main pole, a trailing shield, a write-field-enhancing structure, a write coil, a write current control circuit configured to supply a write current to the write coil to record a bit to a magnetic medium, and a driving current control circuit configured to supply a driving current to the write-field-enhancing structure, wherein the driving current comprises a driving pulse, and wherein the driving current comprises an AC component with a duty cycle selected based at least in part on a power constraint. A method of writing to a magnetic medium comprises supplying a write current to a write coil of a magnetic write head, and supplying a driving current to a free layer disposed in a write gap between a main pole and a trailing shield, wherein the driving current comprises an AC component with a duty cycle based at least in part on a power constraint.
    Type: Application
    Filed: July 1, 2019
    Publication date: October 24, 2019
    Applicant: Western Digital Technologies, Inc.
    Inventors: Gonçalo Marcos Baião DE ALBUQUERQUE, Yunfei DING, Alexander GONCHAROV, Kuok San HO, Daniele MAURI, Goran MIHAJLOVIC, Suping SONG, Petrus Antonius VAN DER HEIJDEN
  • High-bandwidth STO bias architecture with integrated slider voltage potential control
    Patent number: 10424323
    Abstract: Disclosed herein are circuits, architectures, and methods that provide for the control of a data storage device write head's trailing shield and main pole potential with respect to the disk using circuitry that is integrated with circuitry used to bias a spin torque oscillator (STO) apparatus. Various embodiments include slider connections with STO bias circuitry that resides in a read/write integrated circuit, which has a programmable circuit that generates a bias current with overshoot (bias kicks). Also disclosed are circuits that may be incorporated into a slider to mitigate radio-frequency interference.
    Type: Grant
    Filed: March 12, 2018
    Date of Patent: September 24, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: John Contreras, Yunfei Ding, Kuok San Ho, Ian Robson McFadyen, Joey Martin Poss
  • AREAL DENSITY CAPABILITY IMPROVEMENT WITH A MAIN POLE SKIN
    Publication number: 20190279663
    Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole at a media facing surface (MFS), a trailing shield at the MFS, and a heavy metal layer disposed between the main pole and the trailing shield at the MFS. Spin-orbit torque (SOT) is generated from the heavy metal layer and transferred to a surface of the main pole as a current passes through the heavy metal layer in a cross-track direction. The SOT executes a torque on the surface magnetization of the main pole, which reduces the magnetic flux shunting from the main pole to the trailing shield. With the reduced magnetic flux shunting from the main pole to the trailing shield, write-ability is improved.
    Type: Application
    Filed: June 14, 2018
    Publication date: September 12, 2019
    Inventors: Suping SONG, Zhanjie LI, Michael Kuok San HO, Quang LE, Alexander M. ZELTSER
  • SPIN-ORBIT TORQUE INDUCED MAGNETIZATION SWITCHING IN A MAGNETIC RECORDING HEAD
    Publication number: 20190279665
    Abstract: The present disclosure generally relates to magnetic media devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The recording head includes a main pole, a trailing shield hot seed layer, a spin Hall layer disposed between the main pole and the trailing shield hot seed layer, and a spin-torque layer disposed between the main pole and the trailing shield hot seed layer. Spin-orbit torque (SOT) is generated from the spin Hall layer. The spin-torque layer magnetization switching or precession is induced by the SOT. The SOT based head reduces the switching current and the Vjump due to higher spin polarization ratio, which improves energy efficiency. In addition, the spin Hall layer and the spin-torque layer are easier to form compared to the conventional pseudo spin-valve structure.
    Type: Application
    Filed: May 10, 2018
    Publication date: September 12, 2019
    Inventors: Zhanjie LI, Suping SONG, Kuok San HO
  • Dual spin-orbit torque oscillator in magnetic recording
    Patent number: 10403309
    Abstract: The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole, a trailing shield, and an oscillator located between the main pole and the trailing shield. The oscillator is disposed at a media facing surface (MFS). The oscillator includes a spin-torque layer sandwiched between two distinct spin Hall layers. The two distinct spin Hall layers generate spin-orbit torque (SOT) that induces in-plane precessions on opposite surfaces of the spin-torque layer, and both in-plane precessions are in the same direction. The same-direction in-plane precessions on opposite surfaces of the spin-torque layer reduce the critical current of the oscillation of the oscillator, leading to high quality recording.
    Type: Grant
    Filed: January 9, 2019
    Date of Patent: September 3, 2019
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Zhanjie Li, Suping Song, Michael Kuok San Ho
  • MAGNETIC RECORDING WRITE HEAD WITH SELECTED WRITE GAP CURRENT DIRECTION FOR MINIMIZATION OF CROSS-TRACK INTERFERENCE
    Publication number: 20190267029
    Abstract: A magnetic recording write head has an electrically-conductive structure in the write gap between the write pole and the trailing shield and electrical circuitry for directing current through the write gap. The current through the electrically-conductive structure generates a circular Ampere field which, at the disk-facing end of the write pole, is substantially parallel to the disk-facing end of the write pole. The electrically-conductive structure in the write gap may be a STO or an electrically-conductive layer that is not part of a STO. The current direction through the electrically-conductive structure in the write gap is selected so that the generated Ampere field at the write pole end is in substantially the same direction as the magnetization direction of the write head side shields, which has been discovered to result in minimization of cross-track interference.
    Type: Application
    Filed: February 15, 2019
    Publication date: August 29, 2019
    Inventors: Zhigang BAI, Alexander TARATORIN, Anna ZHENG, Venkatesh CHEMBROLU, Supradeep NARAYANA, Suping SONG, Yaguang WEI, Terence LAM, Michael Kuok San HO, Changqing SHI, Lijie GUAN