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).

  • Publication number: 20120251845
    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: Application
    Filed: March 31, 2011
    Publication date: October 4, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Kaizhong Gao
  • Publication number: 20120250404
    Abstract: A magnetic tunnel junction device includes a reference magnetic layer and a magnetic free layer including first and second magnetic elements that are magnetically exchange coupled. The magnetic exchange coupling between the first and second magnetic elements is configured to achieve a switching current distribution less than about 200% and a long term thermal stability criterion of greater than about 60 kBT.
    Type: Application
    Filed: March 31, 2011
    Publication date: October 4, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Kaizhong Gao
  • Publication number: 20120248558
    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: Application
    Filed: May 22, 2012
    Publication date: October 4, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Wenzhong Zhu, Olle Heinonen
  • Patent number: 8279562
    Abstract: A pole tip shield for a write element of a recording head is disclosed. The pole tip shield is spaced from the pole tip in the leading edge direction to provide a magnetic wall angle to reduce ATI or adjacent track erasure to compensate for the skew angle of the head. In illustrated embodiments, the pole tip shield includes side portions. In illustrated embodiments the pole tip shield is generally “U” shaped and side portions of the pole tip shield include different thickness or width dimensions. In illustrated embodiments, the pole tip shield provides a magnetic wall angle for a rectangular shaped pole tip. Embodiments disclosed in the application include a trailing edge shield separated from the pole tip shield along an air bearing surface of the head by a non-magnetic gap portion.
    Type: Grant
    Filed: March 16, 2009
    Date of Patent: October 2, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Jianhua Xue, Yuming Zhou, Dehua Han, Eric S. Linville
  • Patent number: 8264788
    Abstract: An apparatus includes a recording media including a substrate, a plurality of tracks of magnetic material on the substrate, and a non-magnetic material between the tracks; a recording head having an air bearing surface positioned adjacent to the recording media, and including a magnetic pole, an optical transducer, and a near-field transducer, wherein the near-field transducer directs electromagnetic radiation onto tracks to heat portions of the tracks and a magnetic field from the magnetic pole is used to create magnetic transitions in the heated portions of the tracks; and a plasmonic material positioned adjacent to the magnetic material to increase coupling between the electromagnetic radiation and the magnetic material.
    Type: Grant
    Filed: February 23, 2009
    Date of Patent: September 11, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Michael Allen Seigler, Xuhui Jin, Ganping Ju, Bin Lu
  • Patent number: 8248737
    Abstract: A magnetic device includes first and second electrodes and a sensor stack connected to the first and second electrodes proximate a sensing surface of the magnetic sensor. A resistive element is connected to the first and second electrodes in parallel or in series with the sensor stack and adjacent the sensing surface. In some embodiments, the resistive element is configured to generate signals related to changes in its resistance. A controller to respond to the resistive element signals can also be included.
    Type: Grant
    Filed: December 16, 2008
    Date of Patent: August 21, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yonghua Chen, Eric Walter Singleton, Kaizhong Gao, Mohammed Shariat Ullah Patwari, Jason Bryce Gadbois, Daniel Paul Burbank
  • Patent number: 8248891
    Abstract: An apparatus includes a waveguide shaped to direct light to a focal point, and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes a dielectric component and a metallic component positioned adjacent to at least a portion of the dielectric component. An apparatus includes a waveguide shaped to direct light to a focal point, and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes a first metallic component, a first dielectric layer positioned adjacent to at least a portion of the first metallic component, and a second metallic component positioned adjacent to at least a portion of the first dielectric component.
    Type: Grant
    Filed: November 18, 2008
    Date of Patent: August 21, 2012
    Assignee: Seagate Technology LLC
    Inventors: Lien Lee, Xuhui Jin, Kaizhong Gao, Amit Vasant Itagi, William Albert Challener
  • Publication number: 20120206830
    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: Application
    Filed: February 16, 2011
    Publication date: August 16, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Kaizhong Gao, Olle Heinonen, Yonghua Chen
  • Patent number: 8243503
    Abstract: The present invention relates to a memory cell including a first reference layer having a first magnetization with a first magnetization direction and a second reference layer having a second magnetization with a second magnetization direction substantially perpendicular to the first magnetization direction. A storage layer is disposed between the first reference layer and second reference layer and has a third magnetization direction about 45° from the first magnetization direction and about 135° from the second magnetization direction when the memory cell is in a first data state, and a fourth magnetization direction opposite the third magnetization direction when the memory cell is in a second data state.
    Type: Grant
    Filed: December 1, 2010
    Date of Patent: August 14, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Yiming Shi, Song S. Xue, Sining Mao
  • Publication number: 20120201108
    Abstract: Changes in the thermal boundary condition near a close point of an ABS to a media indicate proximity of the ABS with the media. Before contact, heat conduction from the ABS is primarily through convective and/or ballistic heat transfer to air between the ABS and the media. After contact, heat flux primarily flows from the ABS to the media through solid-solid conductive contact. Further, a light source within a HAMR transducer head may create additional thermal variations within the transducer head. These thermal variations create temperature variations within the transducer head. Two resistance temperature sensors on the transducer head at varying distances from the close point and/or light source measure these temperature variations. A temperature difference between the two resistance temperature sensors indicates proximity of the close point to the media and/or light output.
    Type: Application
    Filed: February 8, 2011
    Publication date: August 9, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xuan Zheng, Timothy William Stoebe, Jorge Hanchi, Kaizhong Gao
  • Patent number: 8238062
    Abstract: In some embodiments, a magnetic reader comprises first and second shields extending from an air bearing surface (ABS), a magnetoresistive stack is located between the first and second shields, and a flux guide is separated from the magnetoresistive stack while connecting the first and second shields. The flux guide magnetically couples the distal end of the magnetoresistive stack to the first shield.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: August 7, 2012
    Assignee: Seagate Technology LLC
    Inventors: Yonghua Chen, Jiaoming Qiu, Xilin Peng, Kaizhong Gao
  • Publication number: 20120194945
    Abstract: Cross-track deviation of a writer from a predetermined track on a recording medium is detected. A write current is adjusted based on the cross-track deviation of the writer from the predetermined track. The adjusted write current is applied to the writer to compensate for the cross-track deviation of the writer from the predetermined track.
    Type: Application
    Filed: February 2, 2011
    Publication date: August 2, 2012
    Applicant: Seagate Technology LLC
    Inventor: Kaizhong Gao
  • Publication number: 20120170429
    Abstract: In accordance with certain embodiments, a magnetic head has a coil, which has a lead coil turn positioned between a yoke and an air-bearing surface. In certain embodiments, a magnetic head has a coil, which has a lead coil turn minimally spaced from a main write pole.
    Type: Application
    Filed: June 30, 2011
    Publication date: July 5, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Hua Zhou, Jie Zou, Kaizhong Gao, Amit Itagi
  • Publication number: 20120163139
    Abstract: Thermal energy is generated within an optical NFT when in operation within a HAMR head. A heat-sink assembly within the HAMR head extracts thermal energy from the optical NFT and transmits the thermal energy via convection to air surrounding the HAMR head, radiation to surfaces adjacent to the HAMR head, and/or conduction to other parts of the HAMR head. The thermal energy generated within the optical NFT is conducted to the heat-sink. An air-bearing surface of the heat-sink convectively transfers at least some of the thermal energy to air passing between the air-bearing surface and a surface of an adjacent magnetic medium. Further, some of the thermal energy may also radiatively transfer from the air-bearing surface to the magnetic medium.
    Type: Application
    Filed: December 22, 2010
    Publication date: June 28, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: William Paul Vavra, Xuhui Jin, Xiaoyue Huang, Michael Christopher Kautzky, Kaizhong Gao
  • Patent number: 8203192
    Abstract: Spin-transfer torque memory having a compensation element is disclosed. A spin-transfer torque memory unit includes a free magnetic layer having a magnetic easy axis and a magnetization orientation that can change direction due to spin-torque transfer when a write current passes through the spin-transfer torque memory unit; 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.
    Type: Grant
    Filed: April 14, 2011
    Date of Patent: June 19, 2012
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Wenzhong Zhu, Olle Heinonen
  • Publication number: 20120141834
    Abstract: Aspects include recording media with enhanced areal density through reduction of head media spacing, head keeper spacing, or head to soft underlayer spacing. Such aspects comprise replacing currently non-magnetic components of devices, such as interlayers and overcoats with components and compositions comprising magnetic materials. Other aspects relate to magnetic seed layers deposited within a recording medium. Preferably, these aspects, embodied as methods, systems and/or components thereof reduce effective magnetic spacing without sacrificing physical spacing.
    Type: Application
    Filed: February 13, 2012
    Publication date: June 7, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Kaizhong Gao, Bin Lu, Bogdan Florin Valcu, Xiaoding Ma
  • Publication number: 20120111952
    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: Application
    Filed: November 4, 2010
    Publication date: May 10, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xin Cao, Haiwen Xi, Wenzhong Zhu, Robert Lamberton, Kaizhong Gao
  • Publication number: 20120106001
    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: Application
    Filed: October 29, 2010
    Publication date: May 3, 2012
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Kaizhong Gao, Mourad Benakli
  • Publication number: 20120082866
    Abstract: A perpendicular magnetic media includes a substrate, a patterned template, a seed layer and a magnetic layer. The patterned template is formed on the substrate and includes a plurality of growth sites that are evenly spaced apart from each other. The seed layer is formed over the patterned template and the exposed areas of the substrate. Magnetic material is sputter deposited onto the seed layer with one grain of the magnetic material nucleated over each of the growth sites. The grain size distribution of the magnetic material is reduced by controlling the locations of the growth sites which optimizes the performance of the perpendicular magnetic media.
    Type: Application
    Filed: September 30, 2010
    Publication date: April 5, 2012
    Applicant: Seagate Technology LLC
    Inventors: Shuaigang Xiao, Thomas Young Chang, Yingguo Peng, David Kuo, Kaizhong Gao, Tom Nolan, Ganping Ju
  • Patent number: 8147995
    Abstract: A bit patterned media (BPM) includes many magnetic dots arranged in tracks on a substrate. The magnetic dots each have a hard magnetic core, a soft magnetic cladding surrounding the core and a thin non-magnetic layer that separates the hard magnetic core from the soft magnetic ring. The soft magnetic cladding stabilizes the magnetization at the edges of the hard magnetic core to improve the signal to noise ratio of the magnetic dots. The soft magnetic rings also narrow the magnetic field of the dots which reduces the space requirements and allows more dots to be placed on the substrate.
    Type: Grant
    Filed: July 1, 2009
    Date of Patent: April 3, 2012
    Assignee: Seagate Technology LLC
    Inventors: Haiwen Xi, Kaizhong Gao, Song S. Xue