Patents by Inventor Kaizhong Gao

Kaizhong Gao 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 element with varying stripe heights
    Patent number: 8559140
    Abstract: A magnetically responsive magnetic stack with a first stripe height is positioned laterally adjacent first and second side stacks that respectively extend a second and third distance from an air bearing surface (ABS). The second distance is greater than the third distance capable of biasing the magnetic stack to a predetermined magnetization.
    Type: Grant
    Filed: April 26, 2011
    Date of Patent: October 15, 2013
    Assignee: Seagate Technology LLC
    Inventor: Kaizhong Gao
  • STRAM WITH COMPOSITE FREE MAGNETIC ELEMENT
    Publication number: 20130229862
    Abstract: Spin-transfer torque memory includes a composite free magnetic element, a reference magnetic element having a magnetization orientation that is pinned in a reference direction, and an electrically insulating and non-magnetic tunneling barrier layer separating the composite free magnetic element from the magnetic reference element. The free magnetic element includes a hard magnetic layer exchanged coupled to a soft magnetic layer. The composite free magnetic element has a magnetization orientation that can change direction due to spin-torque transfer when a write current passes through the spin-transfer torque memory unit.
    Type: Application
    Filed: April 15, 2013
    Publication date: September 5, 2013
    Applicant: SEGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Kaizhong Gao, Olle Heinonen, Wenzhong Zhu
  • PLASMONIC FUNNEL FOR FOCUSED OPTICAL DELIVERY TO A METALLIC MEDIUM
    Publication number: 20130223196
    Abstract: An apparatus includes a transducer including a plasmonic funnel having first and second ends with the first end having a smaller cross-sectional area than the second end, and a first section positioned adjacent to the first end of the plasmonic funnel, and a first waveguide having a core, positioned to cause light in the core to excite surface plasmons on the transducer.
    Type: Application
    Filed: February 23, 2012
    Publication date: August 29, 2013
    Applicant: Seagate Technology LLC
    Inventors: Kaizhong Gao, Michael Allen Seigler, Amit Itagi, Jie Zou
  • Transducer head with multiple read sensors
    Patent number: 8508880
    Abstract: In order to improve a consistent data track during writing to a storage medium, a plurality of read sensors are affixed to a transducer head. In one implementation, the transducer head includes multiple read sensors placed up-track of the write pole. In another implementation, the transducer head includes at least one read sensor placed up-track of the write pole and at least one read sensor placed down-track of the write pole. Each position of the multiple read sensors relative to the write pole may be unique. One or more read signals of selected read sensors are used to determine the read location and therefore the write pole location relative to the storage medium.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: August 13, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Olle Heinonen, Yonghua Chen
  • STRAM with compensation element and method of making the same
    Patent number: 8508005
    Abstract: A spin-transfer torque memory unit includes a free magnetic layer having a magnetic easy axis; a reference magnetic element having a magnetization orientation that is pinned in a reference direction; an electrically insulating and non-magnetic tunneling barrier layer separating the free magnetic layer from the magnetic reference element; and a compensation element adjacent to the free magnetic layer. The compensation element applies a bias field on the magnetization orientation of the free magnetic layer. The bias field is formed of a first vector component parallel to the easy axis of the free magnetic layer and a second vector component orthogonal to the easy axis of the free magnetic layer. The bias field reduces a write current magnitude required to switch the direction of the magnetization orientation of the free magnetic layer.
    Type: Grant
    Filed: May 22, 2012
    Date of Patent: August 13, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Wenzhong Zhu, Olle Heinonen
  • Perpendicular magnetic recording media with magnetic anisotropy gradient and local exchange coupling
    Patent number: 8501330
    Abstract: A perpendicular magnetic recording medium adapted for high recording density and high data recording rate comprises a non-magnetic substrate having at least one surface with a layer stack formed thereon, the layer stack including a perpendicular recording layer containing a plurality of columnar-shaped magnetic grains extending perpendicularly to the substrate surface for a length, with a first end distal the surface and a second end proximal the surface, wherein each of the magnetic grains has: (1) a gradient of perpendicular magnetic anisotropy field Hk extending along its length between the first end and second ends; and (2) predetermined local exchange coupling strengths along the length.
    Type: Grant
    Filed: October 11, 2011
    Date of Patent: August 6, 2013
    Assignee: Seagate Technology LLC
    Inventors: Shaoping Li, Kaizhong Gao, Lei Wang, Wenzhong Zhu, Xiaobin Wang
  • Exchange coupled magnetic elements
    Patent number: 8481181
    Abstract: Approaches to reduce switching field distribution in energy assisted magnetic storage devices involve first and second exchange coupled magnetic elements. The first magnetic elements have anisotropy, Hk1, volume, V1 and the second magnetic elements are magnetically exchange coupled to the first magnetic elements and have anisotropy Hk2, and volume V2. The thermal stability of the exchange coupled magnetic elements is greater than about 60 kBT at a storage temperature of about 300 K. The magnetic switching field distribution, SFD, of the exchange coupled magnetic elements is less than about 200% at a predetermined magnetic switching field and a predetermined assisting switching energy.
    Type: Grant
    Filed: March 31, 2011
    Date of Patent: July 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Xiaobin Wang, Kaizhong Gao
  • Pulse writing for bit patterned and continuous media recording
    Patent number: 8477443
    Abstract: Data storage systems are provided. Data storage systems illustratively include a writing element and a recording medium. In some embodiments, the writing element generates first and second magnetization fields that respectively record first and second magnetization patterns to the recording medium. In some embodiments, the writing element is de-saturated between recording the first and second magnetization patterns.
    Type: Grant
    Filed: July 21, 2009
    Date of Patent: July 2, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Olle Gunnar Heinonen, Jianhua Xue, Wenzhong Zhu
  • Light source power control for heat assisted magnetic recording (HAMR)
    Patent number: 8477569
    Abstract: Apparatus and method for light source power control during the writing of data to a storage medium. In accordance with various embodiments, a data recording head is provided having a magnetic transducer and a light source. The light source is driven at a first power level to irradiate an adjacent storage medium prior to the writing if data to the medium using the magnetic transducer. The first power level is insufficient to alter a magnetization state of the medium. The light source is subsequently transitioned to a higher, second power level to irradiate the storage medium during the writing of data to said medium using the magnetic transducer, the second power level being sufficient to alter said magnetization state of the medium.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: July 2, 2013
    Assignee: Seagate Technology LLC
    Inventors: Mehmet Fatih Erden, Edward Charles Gage, Darren W. Karns, Yimin Niu, Kaizhong Gao
  • Recording head for heat assisted magnetic recording with diffusion barrier surrounding a near field transducer
    Patent number: 8477454
    Abstract: An apparatus includes a near field transducer positioned adjacent to an air bearing surface, a first magnetic pole, a heat sink positioned between the first magnetic pole and the near field transducer, and a diffusion barrier positioned between the near field transducer and the first magnetic pole. The diffusion barrier can be positioned adjacent to the magnetic pole or the near field transducer.
    Type: Grant
    Filed: November 15, 2012
    Date of Patent: July 2, 2013
    Assignee: Seagate Technology LLC
    Inventors: Jie Zou, Kaizhong Gao, William Albert Challener, Mark Henry Ostrowski, Venkateswara Rao Inturi, Tong Zhao, Michael Christopher Kautzky
  • Shield with down-track throat region
    Patent number: 8472141
    Abstract: A write element for magnetic recording includes a main pole and a shield. The main pole has first and second sides with respect to a down-track direction. The shield at least partially surrounds the main pole with a continuously concave inner sidewall. The angle between the inner sidewall of the shield and the direction of motion of the write element is greater than the angle between the sides of the main pole and the direction of motion.
    Type: Grant
    Filed: September 12, 2012
    Date of Patent: June 25, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Mourad Benakli
  • Magnetic layers
    Patent number: 8460805
    Abstract: An apparatus includes a first magnetic layer including a plurality of grains. The first magnetic layer has a first anisotropy value. The apparatus also includes a second magnetic layer including a plurality of grains. The second magnetic layer has a second anisotropy value that is different than the first anisotropy value. The apparatus also includes an exchange tuning layer including a plurality of grains and located between the first and second magnetic layers. The exchange tuning layer has stronger inter-granular exchange coupling than the first and second magnetic layers. The exchange tuning layer has an anisotropy value less than the first and second anisotropy values.
    Type: Grant
    Filed: December 23, 2010
    Date of Patent: June 11, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Yingguo Peng
  • Bit-patterned stack with antiferromagnetic shell
    Patent number: 8455117
    Abstract: A method of producing bit-patterned media is provided whereby a shell structure is added on a bit-patterned media dot. The shell may be an antiferromagnetic material that will help stabilize the magnetization configuration at the remanent state due to exchange coupling between the dot and its shell. Therefore, this approach also improves the thermal stability of the media dot and helps each individual media dot maintain a single domain state.
    Type: Grant
    Filed: March 4, 2009
    Date of Patent: June 4, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Song Xue
  • Plasmonic transducer having two metal elements with a gap disposed therebetween
    Patent number: 8451705
    Abstract: An apparatus includes a waveguide configured to deliver light to a transducer region. The apparatus also includes a plasmonic transducer that has two metal elements configured as side-by-side plates on a substrate-parallel plane with a gap therebetween. The gap is disposed along the substrate-parallel plane and has an input end disposed proximate the transducer region and an output end. The transducer is configured to provide a surface plasmon-enhanced near-field radiation pattern proximate the output end in response to the light received by the waveguide.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: May 28, 2013
    Assignee: Seagate Technology LLC
    Inventors: Chubing Peng, Kaizhong Gao, Lien Lee, Amit Vasant Itagi, Michael Allen Seigler, Yimin Niu, Sethuraman Jayashankar
  • Recording Head for Heat Assisted Magnetic Recording with a Side Lobe Blocker
    Publication number: 20130100783
    Abstract: An apparatus includes a waveguide having a core layer, a near field transducer having an end positioned adjacent to a first surface, a first magnetic pole having an end positioned adjacent to the first surface, and a side lobe blocker adjacent to the first surface and having portions on opposite sides of the first magnetic pole and the near field transducer, wherein the side lobe blocker forms an aperture at an end of the core layer adjacent to the first surface.
    Type: Application
    Filed: October 25, 2011
    Publication date: April 25, 2013
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Mark Henry Ostrowski, Jie Zou, Amit Itagi, Kaizhong Gao
  • Field assisted switching of a magnetic memory element
    Patent number: 8422277
    Abstract: Method and apparatus for writing data to a magnetic memory element, such as a spin-torque transfer random access memory (STRAM) memory cell. In accordance with various embodiments, a write current is applied through a magnetic memory element to initiate magnetic precession of the element to a desired magnetic state. A flow of a field assist current is subsequently initiated adjacent the magnetic memory element during continued application of the write current to induce a magnetic field upon the element. The field assist current persists after the write current is terminated to provide field assisted precession to the desired magnetic state.
    Type: Grant
    Filed: November 4, 2010
    Date of Patent: April 16, 2013
    Assignee: Seagate Technology LLC
    Inventors: Xin Cao, Haiwen Xi, Wenzhong Zhu, Robert Lamberton, Kaizhong Gao
  • STRAM with composite free magnetic element
    Patent number: 8422279
    Abstract: Spin-transfer torque memory includes a composite free magnetic element, a reference magnetic element having a magnetization orientation that is pinned in a reference direction, and an electrically insulating and non-magnetic tunneling barrier layer separating the composite free magnetic element from the magnetic reference element. The free magnetic element includes a hard magnetic layer exchanged coupled to a soft magnetic layer. The composite free magnetic element has a magnetization orientation that can change direction due to spin-torque transfer when a write current passes through the spin-transfer torque memory unit.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: April 16, 2013
    Assignee: Seagate Technology LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Kaizhong Gao, Olle Heinonen, Wenzhong Zhu
  • Microwave-assisted magnetic recording with collocated microwave and write fields
    Patent number: 8422159
    Abstract: Methods and devices are provided for microwave-assisted magnetic recording with collocated microwave and write fields. An illustrative device includes a magnetic write pole and one or more alternating-field components. The magnetic write pole is configured for providing a magnetic write field. The one or more alternating-field components are disposed to at least partially coincide with the magnetic write pole. The one or more alternating-field components are configured to provide an alternating magnetic field having a microwave frequency and an orientation that is at least partially transverse to the magnetic write field.
    Type: Grant
    Filed: June 4, 2009
    Date of Patent: April 16, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Alexandru Cazacu, Robert William Lamberton, Michael Leigh Mallary
  • Write head with bevel structure and reverse NFT for HAMR
    Patent number: 8416530
    Abstract: A magnetic recording head comprises a write pole tip adjacent to an air bearing surface and a return pole. In addition, a near field transducer is positioned adjacent the write pole in order to produce near field radiation to heat a portion of a recording medium to facilitate switching by the magnetic write pole. The near field transducer is a reverse optical near field transducer with internal bevel structures that enhance the magnetic write field intensity.
    Type: Grant
    Filed: October 20, 2009
    Date of Patent: April 9, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Xuhui Jin, Arkadi Goulakov
  • Magnetic main write pole
    Patent number: 8405931
    Abstract: A magnetic writer includes a write pole configured such that the easy magnetic axis is parallel to the vertical length direction of the write pole tip and to the ABS of the recording media. The write pole tip can be a multilayer structure comprising alternating magnetic and nonmagnetic layers with a planar orientation substantially perpendicular to the ABS and with magnetic anisotropy parallel to the vertical length direction of the write pole tip. The alternating magnetic and nonmagnetic layers may be formed by electroplating on a conformal seedlayer in a trench, or by static off axis physical vapor deposition.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: March 26, 2013
    Assignee: Seagate Technology LLC
    Inventors: Mark T. Kief, Kaizhong Gao, Venkateswara Rao Inturi