Patents by Inventor Simon Liao

Simon Liao 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: 20030179517
    Abstract: Patterned, longitudinally and transversely antiferromagnetically exchange biased GMR sensors are provided which have narrow effective trackwidths and reduced side reading. The exchange biasing significantly reduces signals produced by the portion of the ferromagnetic free layer that is underneath the conducting leads while still providing a strong pinning field to maintain sensor stability. In the case of the transversely biased sensor, the magnetization of the free and biasing layers in the same direction as the pinned layer simplifies the fabrication process and permits the formation of thinner leads by eliminating the necessity for current shunting.
    Type: Application
    Filed: March 22, 2002
    Publication date: September 25, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: Cheng T. Horng, Min Li, Ru-Ying Tong, Yun-Fei Li, You Feng Zheng, Simon Liao, Kochan Ju, Cherng Chyi Han
  • Publication number: 20030156361
    Abstract: A patterned, synthetic, longitudinally exchange biased GMR sensor is provided which has a narrow effective trackwidth and reduced side reading. The advantageous properties of the sensor are obtained by satisfying a novel relationship between the magnetizations (M) of the ferromagnetic free layer (F1) and the ferromagnetic biasing layer (F2) which enables the optimal thicknesses of those layers to be determined for a wide range of ferromagnetic materials and exchange coupling materials. The relationship to be satisfied is MF2/MF1=(Js+Jex)/Js, where Js is the synthetic coupling energy between F1 and F2 and Jex is the exchange energy between F2 and an overlaying antiferromagnetic pinning layer. An alternative embodiment omits the overlaying antiferromagnetic pinning layer which causes the relationship to become MF2/MF1=1.
    Type: Application
    Filed: February 15, 2002
    Publication date: August 21, 2003
    Inventors: Min Li, You Feng Zheng, Simon Liao, Kochan Ju
  • Patent number: 6594124
    Abstract: An improved stabilization scheme for a GMR read head is described. Two important changes relative to prior art designs have been introduced. Instead of biasing by means of a permanent magnet or through exchange coupling with an antiferromagnetic layer, the magnetostatic field emanating from a nearby, but not contiguous, layer is used. Additionally, to obtain optimum stability with this scheme the bias, instead of running parallel to the easy axis of the free layer, is canted away from it towards the direction of the demagnetizing field of the pinned layer. A process for the manufacture of the structure is also described.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: July 15, 2003
    Assignee: Headway Technologies, Inc.
    Inventors: You Feng Zheng, Kochan Ju, Simon Liao
  • Publication number: 20030087133
    Abstract: An improved stabilization scheme for a GMR read head is described. Two important changes relative to prior art designs have been introduced. Instead of biasing by means of a permanent magnet or through exchange coupling with an antiferromagnetic layer, the magnetostatic field emanating from a nearby, but not contiguous, layer is used. Additionally, to obtain optimum stability with this scheme the bias, instead of running parallel to the easy axis of the free layer, is canted away from it towards the direction of the demagnetizing field of the pinned layer. A process for the manufacture of the structure is also described.
    Type: Application
    Filed: November 6, 2001
    Publication date: May 8, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: You Feng Zheng, Kochan Ju, Simon Liao
  • Publication number: 20030053267
    Abstract: A method for forming top and bottom spin valve sensors and the sensors so formed, the sensors having a strongly coupled SyAP pinned layer and an ultra-thin antiferromagnetic pinning layer. The two strongly coupled ferromagnetic layers comprising the SyAP pinned layer in the top valve configuration are separated by a Ru spacer layer approximately 3 angstroms thick, while the two layers in the bottom spin valve configuration are separated by a Rh spacer layer approximately 5 angstroms thick. This allows the use of an ultra thin MnPt antiferromagnetic pinning layer of thickness between approximately 80 and approximately 150 angstroms. The sensor structure produced thereby is suitable for high density applications.
    Type: Application
    Filed: September 17, 2001
    Publication date: March 20, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: Cheng T. Horng, Kochan Ju, Mao-Min Chen, Min Li, Ru-Ying Tong, Simon Liao
  • Publication number: 20030053266
    Abstract: Nano-oxide based current-perpendicular-to-plane (CPP) magnetoresistive (MR) sensor stacks are provided, together with methods for forming such stacks. Such stacks have increased resistance and enhanced magnetoresistive properties relative to CPP stacks made entirely of metallic layers. Said enhanced properties are provided by the insertion of magnetic nano-oxide layers between ferromagnetic layers and non-magnetic spacer layers, whereby said nano-oxide layers increase resistance and exhibit spin filtering properties. CPP sensor stacks of various types are provided, all having nano-oxide layers formed therein, including the spin-valve type and the synthetic antiferromagnetic pinned layer spin-valve type. Said stacks can also be formed upon each other to provide laminated stacks of different types.
    Type: Application
    Filed: September 17, 2001
    Publication date: March 20, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: Bernard Dieny, Cheng Horng, Kochan Ju, Min Li, Simon Liao
  • Publication number: 20030039079
    Abstract: As the dimensions of spin valve heads continue to be reduced, a number of difficulties are being encountered. One such is with the longitudinal bias when an external magnetic field can cause reversal of the hard magnet, thereby causing a hysteric response by the head. This coercivity reduction becomes more severe as the hard magnet becomes thinner. This problem has been overcome by inserting a decoupling layer between the antiferromagnetic layer that is used to stabilize the pinned layer of the spin valve itself and the soft ferromagnetic layer that is used for longitudinal biasing. This soft ferromagnetic layer is pinned by a second antiferromagnetic layer deposited on it on its far side away from the first antiferromagnetic layer. The presence of the decoupling layer ensures that the magnetization of the soft layer is determined only by the second antiferromagnetic layer. The inclusion of said decoupling layer allows more latitude in etch depth control during manufacturing.
    Type: Application
    Filed: August 22, 2001
    Publication date: February 27, 2003
    Applicant: Headway Technologies, Inc.
    Inventors: You Feng Zheng, Kochan Ju, Cheng T. Horng, Simon Liao, Ru Ying Tong
  • Patent number: 5748416
    Abstract: An SAL-type magnetoresistive playback head that is highly sensitive and that limits Barkhausen noise is provided by optimizing the magnetic properties of the permanent magnet film. On top of a lower insulating layer are stacked a soft magnetic bias film (SAL film), a magnetic separating film (shunt film), a magnetoresistive film (MR film), and an upper insulating layer, in that order. The outer sides of the track of the MR film are in direct contact with the permanent magnet film or in indirect contact via a base film. Alternatively, the present invention relates to a spin-valve magnetoresistive playback head. On top of a lower insulating layer are stacked an anti-ferromagnetic film, a fixed magnetizing film, a magnetic separating film, a movable magnetizing film (MR film), and an upper insulating layer, in that order. The outer sides of the track of the movable magnetizing film are in direct contact with the permanent magnet film or in indirect contact via a base film.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: May 5, 1998
    Assignees: Hitachi Metals Ltd., Applied Magnetics Corporation
    Inventors: Masahiro Tobise, Chiharu Mitsumata, Hisayuki Miura, Tetsurou Kawai, Simon Liao
  • Patent number: 4992901
    Abstract: In a method of manufacturing a thin film magnetic head having aligned top and bottom pole tip pieces, a sacrificial mask protects the upper pole tip while the exposed non-aligned portions of the gap material and lower pole tip are removed. The sacrificial mask is deposited using a self alignment technique.
    Type: Grant
    Filed: February 15, 1990
    Date of Patent: February 12, 1991
    Assignee: Seagate Technology, Inc.
    Inventors: Beat Keel, Arthur Calderon, Simon Liao