Patents by Inventor Tong Zhao

Tong Zhao 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).

  • TMR device with novel free layer structure
    Patent number: 8385027
    Abstract: A composite free layer having a FL1/insertion/FL2 configuration is disclosed for achieving high dR/R, low RA, and low ? in TMR or GMR sensors. Ferromagnetic FL1 and FL2 layers have (+) ? and (?) ? values, respectively. FL1 may be CoFe, CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb. FL2 may be CoFe, NiFe, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, Nb, or B. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. In a TMR stack with a MgO tunnel barrier, dR/R>60%, ?˜1×10?6, and RA=1.2 ohm-um2 when FL1 is CoFe/CoFeB/CoFe, FL2 is CoFe/NiFe/CoFe, and the insertion layer is CoTa or CoFeBTa.
    Type: Grant
    Filed: October 19, 2011
    Date of Patent: February 26, 2013
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui-Chuan Wang, Min Li, Kunliang Zhang
  • ANTIMICROBIAL TREATMENT FOR SEEDS AND SPROUTS
    Publication number: 20130005811
    Abstract: The present disclosure encompasses embodiments of a method of reducing the microbial load of a vegetable seed or a sprout thereof, comprising contacting the vegetable seed or the sprout thereof, with a composition comprising levulinic acid and a detergent for a period suitable for reducing a bacterial population of the vegetable seed or the sprout thereof. In embodiments of the methods of the disclosure, the composition can reduce a bacterial population located on the exterior surface of the seed coat (testa) of a vegetable seed, located in or on the seed contents beneath the testa, or located on and beneath the testa of the vegetable seed.
    Type: Application
    Filed: March 9, 2011
    Publication date: January 3, 2013
    Inventors: Ronald Walcott, Michael Doyle, Tong Zhao
  • TMR Device with Novel Free Layer Structure
    Publication number: 20130001189
    Abstract: A composite free layer having a FL1/insertion/FL2 configuration where a top surface of FL1 is treated with a weak plasma etch is disclosed for achieving enhanced dR/R while maintaining low RA, and low ? in TMR or GMR sensors. The weak plasma etch removes less than about 0.2 Angstroms of FL1 and is believed to modify surface structure and possibly increase surface energy. FL1 may be CoFe, CoFe/CoFeB, or alloys thereof having a (+) ? value. FL2 may be CoFe, NiFe, or alloys thereof having a (?) ? value. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element. When CoFeBTa is selected as insertion layer, the CoFeB:Ta ratio is from 1:1 to 4:1.
    Type: Application
    Filed: July 30, 2012
    Publication date: January 3, 2013
    Applicant: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui Chuan Wang, Min Li, Kunliang Zhang
  • Low resistance tunneling magnetoresistive sensor with natural oxidized double MgO barrier
    Patent number: 8337676
    Abstract: A high performance TMR sensor is fabricated by incorporating a tunnel barrier having a Mg/MgO/Mg configuration. The 4 to 14 Angstroms thick lower Mg layer and 2 to 8 Angstroms thick upper Mg layer are deposited by a DC sputtering method while the MgO layer is formed by a NOX process involving oxygen pressure from 0.1 mTorr to 1 Torr for 15 to 300 seconds. NOX time and pressure may be varied to achieve a MR ratio of at least 34% and a RA value of 2.1 ohm-um2. The NOX process provides a more uniform MgO layer than sputtering methods. The second Mg layer is employed to prevent oxidation of an adjacent ferromagnetic layer. In a bottom spin valve configuration, a Ta/Ru seed layer, IrMn AFM layer, CoFe/Ru/CoFeB pinned layer, Mg/MgO/Mg barrier, CoFe/NiFe free layer, and a cap layer are sequentially formed on a bottom shield in a read head.
    Type: Grant
    Filed: August 5, 2010
    Date of Patent: December 25, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Kunliang Zhang, Hui Chuan Wang, Yu-Hsia Chen, Min Li
  • TMR or CPP structure with improved exchange properties
    Patent number: 8339754
    Abstract: An insertion layer is provided between an AFM layer and an AP2 pinned layer in a GMR or TMR element to improve exchange coupling properties by increasing Hex and the Hex/Hc ratio without degrading the MR ratio. The insertion layer may be a 1 to 15 Angstrom thick amorphous magnetic layer comprised of at least one element of Co, Fe, or Ni, and at least one element having an amorphous character selected from B, Zr, Hf, Nb, Ta, Si, or P, or a 1 to 5 Angstrom thick non-magnetic layer comprised of Cu, Ru, Mn, Hf, or Cr. Preferably, the content of the one or more amorphous elements in the amorphous magnetic layer is less than 40 atomic %. Optionally, the insertion layer may be formed within the AP2 pinned layer. Examples of an insertion layer are CoFeB, CoFeZr, CoFeNb, CoFeHf, CoFeNiZr, CoFeNiHf, and CoFeNiNbZr.
    Type: Grant
    Filed: June 30, 2011
    Date of Patent: December 25, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Hui-Chuan Wang, Tong Zhao, Min Li
  • Recording head for heat assisted magnetic recording with diffusion barrier surrounding a near field transducer
    Patent number: 8339740
    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: February 23, 2011
    Date of Patent: December 25, 2012
    Assignee: Seagate Technology LLC
    Inventors: Jie Zou, Kaizhong Gao, William Albert Challener, Mark Henry Ostrowski, Venkateswara Rao Inturi, Tong Zhao, Michael Christopher Kautzky
  • Magnetic memory cell
    Patent number: 8335105
    Abstract: By inserting a spin polarizing layer (typically pure iron) within the free layer of a MTJ or GMR memory cell, dR/R can be improved without significantly affecting other free layer properties such as Hc. Additional performance improvements can be achieved by also inserting a surfactant layer (typically oxygen) within the free layer.
    Type: Grant
    Filed: March 7, 2007
    Date of Patent: December 18, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Hui-Chuan Wang, Tong Zhao, Kunliang Zhang, Min Li
  • Pinning field in MR devices despite higher annealing temperature
    Patent number: 8325448
    Abstract: The pinning field in an MR device was significantly improved by using the Ru 4A peak together with steps to minimize interfacial roughness of the ruthenium layer as well as boron and manganese diffusion into the ruthenium layer during manufacturing. This made it possible to anneal at temperatures as high as 340° C. whereby a high MR ratio could be simultaneously achieved.
    Type: Grant
    Filed: February 11, 2011
    Date of Patent: December 4, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Shengyuan Wang, Tong Zhao, Min Li, Hui-Chuan Wang
  • Ultra low RA (resistance x area) sensors having a multilayer non-magnetic spacer between pinned and free layers
    Patent number: 8289663
    Abstract: A high performance TMR sensor with a spacer including at least one metal layer such as Cu and one or more MgO layers is disclosed. In addition, there may be a metal dopant in the MgO layer. In an alternative embodiment, the MgO layer may be replaced by other low band gap insulating or semiconductor materials. An ultra-low RA of <0.4 ?ohm-cm2 in combination with a MR of 14%, low magnetostriction, and a low Hin value of about 20 Oe is achieved with a composite spacer of the present invention. The Cu layer thickness is from 0.1 to 10 Angstroms and the MgO thickness is from 5 to 20 Angstroms in spacer configurations including Cu/MgO/Cu, and MgO/Cu/MgO.
    Type: Grant
    Filed: April 25, 2008
    Date of Patent: October 16, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Tong Zhao, Hui-Chuan Wang, Min Li
  • TMR Device with Improved MgO Barrier
    Publication number: 20120235258
    Abstract: A method of forming a high performance magnetic tunnel junction (MTJ) is disclosed wherein the tunnel barrier includes at least three metal oxide layers. The tunnel barrier stack is partially built by depositing a first metal layer, performing a natural oxidation (NOX) process, depositing a second metal layer, and performing a second NOX process to give a MOX1/MOX2 configuration. An uppermost metal layer on the MOX2 layer is not oxidized until after the MTJ stack is completely formed and an annealing process is performed to drive unreacted oxygen in the MOX1 and MOX2 layers into the uppermost metal layer. In an alternative embodiment, a plurality of metal oxide layers is formed on the MOX1 layer before the uppermost metal layer is deposited. The resulting MTJ stack has an ultralow RA around 1 ohm-?m2 and maintains a high magnetoresistive ratio characteristic of a single metal oxide tunnel barrier layer.
    Type: Application
    Filed: May 29, 2012
    Publication date: September 20, 2012
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Tong Zhao, Hui-Chuan Wang, Min Li, Kunliang Zhang
  • TMR device with novel free layer structure
    Patent number: 8259420
    Abstract: A composite free layer having a FL1/insertion/FL2 configuration where a top surface of FL1 is treated with a weak plasma etch is disclosed for achieving enhanced dR/R while maintaining low RA, and low ? in TMR or GMR sensors. The weak plasma etch removes less than about 0.2 Angstroms of FL1 and is believed to modify surface structure and possibly increase surface energy. FL1 may be CoFe, CoFe/CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb having a (+) ? value. FL2 may be CoFe, NiFe, or alloys thereof having a (?) ? value. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. When CoFeBTa is selected as insertion layer, the CoFeB:Ta ratio is from 1:1 to 4:1.
    Type: Grant
    Filed: February 1, 2010
    Date of Patent: September 4, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui Chuan Wang, Min Li, Kunliang Zhang
  • Pinning field in MR devices despite higher annealing temperature
    Publication number: 20120205757
    Abstract: The pinning field in an MR device was significantly improved by using the Ru 4A peak together with steps to minimize interfacial roughness of the ruthenium layer as well as boron and manganese diffusion into the ruthenium layer during manufacturing. This made it possible to anneal at temperatures as high as 340° C. whereby a high MR ratio could be simultaneously achieved.
    Type: Application
    Filed: February 11, 2011
    Publication date: August 16, 2012
    Inventors: Kunliang Zhang, Shengyuan Wang, Tong Zhao, Min Li, Hui-Chuan Wang
  • TMR Device with Low Magnetorestriction Free Layer
    Publication number: 20120193738
    Abstract: A high performance TMR sensor is fabricated by employing a free layer with a trilayer configurations represented by FeCo/CoFeB/CoB, FeCo/CoB/CoFeB, FeCo/CoFe/CoB, or FeCo/FeB/CoB may also be employed. Alternatively, CoNiFeB or CoNiFeBM formed by co-sputtering CoB with CoNiFe or CoNiFeM, respectively, where M is V, Ti, Zr, Nb, Hf, Ta, or Mo may be included in a composite free layer or as a single free layer in the case of CoNiFeBM. A 15 to 30% in improvement in TMR ratio over a conventional CoFe/NiFe free layer is achieved while maintaining low Hc and RA <3 ohm-um2. In bilayer or trilayer embodiments, magnetostriction (?) between ?5×10?6 and 5×10?6 is achieved by combining CoB (??) and one or more layers having a positive ?.
    Type: Application
    Filed: April 11, 2012
    Publication date: August 2, 2012
    Applicant: HEADWAY TECHNOLOGIES, INC.
    Inventors: Hui-Chuan Wang, Tong Zhao, Min Li, Kunliang Zhang
  • Reconfigurable electric circuitry and method of making same
    Patent number: 8227701
    Abstract: A reconfigurable electric circuit includes first and second crystalline material layers positioned adjacent to each other and forming a first interface, and a first ferroelectric layer positioned adjacent to the first crystalline material layer and having ferroelectric domains applying an electric field to regions of the first interface to induce a quasi two-dimensional electron gas in the regions, wherein at least one of the regions forms a gate and at least one of the regions forms a channel.
    Type: Grant
    Filed: January 26, 2009
    Date of Patent: July 24, 2012
    Assignee: Seagate Technology LLC
    Inventors: Stephen John Wrazien, Florin Zavaliche, Joachim Walter Ahner, Tong Zhao, Martin Gerard Forrester, Shan Hu
  • TMR device with improved MgO barrier
    Patent number: 8202572
    Abstract: A method of forming a high performance magnetic tunnel junction (MTJ) is disclosed wherein the tunnel barrier includes at least three metal oxide layers. The tunnel barrier stack is partially built by depositing a first metal layer, performing a natural oxidation (NOX) process, depositing a second metal layer, and performing a second NOX process to give a MOX1/MOX2 configuration. An uppermost metal layer on the MOX2 layer is not oxidized until after the MTJ stack is completely formed and an annealing process is performed to drive unreacted oxygen in the MOX1 and MOX2 layers into the uppermost metal layer. In an alternative embodiment, a plurality of metal oxide layers is formed on the MOX1 layer before the uppermost metal layer is deposited. The resulting MTJ stack has an ultralow RA around 1 ohm-?m2 and maintains a high magnetoresistive ratio characteristic of a single metal oxide tunnel barrier layer.
    Type: Grant
    Filed: November 22, 2010
    Date of Patent: June 19, 2012
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui-Chuan Wang, Min Li, Kunliang Zhang
  • Antimicrobial Composition and Use as Food Treatment
    Publication number: 20120148716
    Abstract: Antimicrobial compositions are provided comprising a pharmaceutically acceptable organic acid and a pharmaceutically acceptable surfactant. This synergistic combination allows compositions to be formulated at low concentrations that have efficacy in reducing bacterial counts by greater than 3 log within 5 minutes of contact while preserving the organoleptic properties of treated foods, including fresh produce. Also provided are methods for the use of the compositions to reduce the microbial load on the surfaces of foodstuffs, processed food products, and the hard surfaces of food preparation machinery, tools, benches, and the like.
    Type: Application
    Filed: February 1, 2012
    Publication date: June 14, 2012
    Applicant: University of Georgia Research Foundation
    Inventors: Michael P. Doyle, Tong Zhao
  • Control of Enterohemorrhagic E. Coli in Farm Animal Drinking Water
    Publication number: 20120141607
    Abstract: The present invention relates to a new composition and methods for preventing the transmission of enterohemorrhagic E. coli and other foodborne pathogens to farm animals. In accordance with one embodiment, a composition comprising lactic acid and acidic calcium sulfate, and a compound selected from the group consisting of caprylic acid, sodium benzoate, butyric acid and chlorine dioxide is provided as an inhibitor of the growth of enterohemorrhagic E. coli and other foodborne pathogens.
    Type: Application
    Filed: February 13, 2012
    Publication date: June 7, 2012
    Applicant: UNIVERSITY OF GEORGIA RESEARCH FOUNDATION
    Inventors: Michael P. Doyle, Tong Zhao
  • Chlorine-Free Liquid Microbicide Treatment
    Publication number: 20120129928
    Abstract: The combination of the surfactant SDS with levulinic acid produces a synergistic effect in relation to the antimicrobial effectiveness of the individual compounds. Accordingly, this surprising synergy allows the formulation of compositions wherein the active agents are present at concentrations effective to reduce bacterial counts in liquids, including, but not limited to, water and other beverages, especially those having a pH value less than about 7.0 by a factor between 103 and 107 without altering the organoleptic properties of the treated food substance. The active agents are FDA-approved as food additives, and the treated beverages can be any aqueous-based beverage consumable by humans or animals.
    Type: Application
    Filed: January 17, 2012
    Publication date: May 24, 2012
    Applicant: University of Georgia Research Foundation, Inc.
    Inventors: Michael P. Doyle, Tong Zhao
  • TMR DEVICE WITH IMPROVED MGO BARRIER
    Publication number: 20120128870
    Abstract: A method of forming a high performance magnetic tunnel junction (MTJ) is disclosed wherein the tunnel barrier includes at least three metal oxide layers. The tunnel barrier stack is partially built by depositing a first metal layer, performing a natural oxidation (NOX) process, depositing a second metal layer, and performing a second NOX process to give a MOX1/MOX2 configuration. An uppermost metal layer on the MOX2 layer is not oxidized until after the MTJ stack is completely formed and an annealing process is performed to drive unreacted oxygen in the MOX1 and MOX2 layers into the uppermost metal layer. In an alternative embodiment, a plurality of metal oxide layers is formed on the MOX1 layer before the uppermost metal layer is deposited. The resulting MTJ stack has an ultralow RA around 1 ohm-?m2 and maintains a high magnetoresistive ratio characteristic of a single metal oxide tunnel barrier layer.
    Type: Application
    Filed: November 22, 2010
    Publication date: May 24, 2012
    Inventors: Tong Zhao, Hui-Chuan Wang, Min Li, Kunliang Zhang
  • VIRICIDAL AND MICROBICIDAL COMPOSITIONS AND USES THEREOF
    Publication number: 20120121679
    Abstract: The present disclosure encompasses compositions comprising a surfactant, and an acid such as, but not limited to, levulinic acid, that together have a synergistic effect in reducing the viability of a virus population compared to the efficacy of the individual compounds. This synergy allows the formulation of compositions where the active agents (including an acid and a surfactant) are present at concentrations effective to inactivate viruses on surfaces, including human skin. The viricidal compositions disclosed herein are efficacious without damaging the surface to which they may be applied, or even altering the organoleptic properties of a treated food substance. The viricidal compositions and wipes containing such compositions are suitable for sanitizing any surface suspected of having a viral load thereon, or where it is desirable to ensure that a viral load is as low as possible.
    Type: Application
    Filed: January 13, 2012
    Publication date: May 17, 2012
    Applicant: University of Georgia Research Foundation, Inc.
    Inventors: Jennifer L. Cannon, Michael Patrick Doyle, Tong Zhao