Recent Submissions

  • Phase Transformation and Magnetic Hardening in Isolated FePt Nanoparticles 

    Liu, J. Ping; Rong, Chuan-bing; Nandwana, Vikas; Poudyal, Narayan; Chaubey, Girija S. (IEEE XploreIEEEDepartment of Physics, The University of Texas at Arlington, 2009-07)
    Isolated monodisperseL10 FePt nanoparticles coated by carbon were obtained by adding enough surfactants that decomposed into carbon after the chemical synthesis and postannealing of the A1 FePt nanoparticles. The effect ...
  • Phase Transformation and Magnetic Hardening in Isolated FePt Nanoparticles 

    Liu, J. Ping; Rong, Chuanbing; Nandwana, Vikas; Poudyal, Narayan; Chaubey, Girija Shankar (IEEEDepartment of Physics, The University of Texas at Arlington, 2009-03-31)
    Isolated monodisperse L1[subscript]0 FePt nanoparticles coated by carbon were obtained by adding enough surfactants that decomposed into carbon after the chemical synthesis and postannealing of the A1 FePt nanoparticles. ...
  • Transformation of electrical transport from variable range hopping to hard gap resistance in Zn[subscript]1−[subscript]xFe[subscript]xO[subscript]1[subscript]v magnetic semiconductor films 

    Tian, Y.F.; Yan, Shi-shen; Zhang, Y.P.; Song, H.Q.; Ji, G.; Liu, G.L.; Mei, M.L.; Liu, J. Ping; Altuncevahir, B.; Chakka, V.; Chen, Y.X. (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2006-11-16)
    Transformation of the electrical transport from the Efros and Shklovskii [J. Phys. C 8, L49 (1975)] variable range hopping to the “hard gap” resistance was experimentally observed in a low temperature range as the Fe ...
  • Observation of L1[subscript]0-like chemical ordering in a decahedral FePt nanoparticle by C[subscript]s-corrected high resolution transmission electron microscopy 

    Hu, Xuerang; Xie, Lin; Zhu, Jing; Poudyal, Narayan; Liu, J. Ping; Yuan, Jun (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-03-09)
    The state of the chemical ordering in a decahedral FePt nanoparticle was studied using aberration corrected high resolution transmission electron microscopy. With the reduced image delocalization effect as a result of ...
  • Bulk FePt/Fe3Pt nanocomposite magnets prepared by spark plasma sintering 

    Rong, Chuanbing; Nandwana, Vikas; Poudyal, Narayan; Liu, J. Ping; Saito, Tetsuji; Wu, Yaqiao; Kramer, Matthew J. (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-04-27)
    FePt/Fe3Pt bulk nanocomposite magnets have been prepared by the spark plasma sintering of chemically synthesized FePt and Fe3O4 nanoparticles under 100 MPa at 400–600 °C. It was found that the phase transition of the FePt ...
  • Anisotropic nanostructured magnets by magnetic-field-assisted processing 

    Rong, Chuanbing; Nguyen, Van Vuong; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2010-04-15)
    It has been a great challenge to produce anisotropic nanocrystalline bulk magnets. In this paper, we report our recent work in preparing anisotropic bonded magnets consisting of SmCo5 nanocrystalline particles. The work ...
  • Effect of thermal fluctuations on the recoil loops of SmCo5[subscript]/Fe nanocomposite system 

    Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-02-13)
    The correlation between the recoil loop openness and the activation volume has been studied for the SmCo5/α-Fe nanocomposite powder material prepared by mechanical alloying. The α-Fe phase content in the nanocomposite ...
  • Effects of particle size and composition on coercivity of Sm–Co nanoparticles prepared by surfactant-assisted ball milling 

    Poudyal, Narayan; Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2010-04-15)
    The correlation between the recoil loop openness and the activation volume has been studied for the SmCo5/α-Fe nanocomposite powder material prepared by mechanical alloying. The α-Fe phase content in the nanocomposite ...
  • Fabrication of bulk nanocomposite magnets via severe plastic deformation and warm compaction, 

    Rong, Chuanbing; Zhang, Ying; Poudyal, Narayan; Xiong, Xiangyuan; Kramer, Matthew J.; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2010-03-10)
    We demonstrate that a SmCo/FeCo based hard/soft nanocomposite material can be fabricated by distributing the soft magnetic α-Fe phase particles homogeneously in a hard magnetic SmCo phase through severe plastic deformation. ...
  • Rapid thermal annealing of FePt nanoparticles 

    Yano, Kazuaki; Nandwana, Vikas; Poudyal, Narayan; Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2008-07-11)
    We report a systematic study on rapid thermal annealing (RTA) of FePt nanoparticles. FePt particles with an average size of 8 nm were synthesized by a chemical solution method, and then annealed using RTA and conventional ...
  • First-principles prediction of enhanced magnetic anisotropy in FeCo alloys 

    Wu, Dangxin; Zhang, Qiming; Liu, J. Ping; Yuan, Dingwang; Wu, Ruqian (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2008-02-04)
    The structural, electronic, and magnetic properties of FeCo alloys were studied by first-principles calculations. It has been found that the alloys prefer chemically noncubic geometries in a wide composition range. This ...
  • Bimagnetic nanoparticles with enhanced exchange coupling and energy products 

    Nandwana, Vikas; Chaubey, Girija Shankar; Yano, Kazuaki; Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-01-06)
    Bimagnetic FePt/Fe3O4 nanoparticles with core/shell or heterodimer structure have been prepared using a sequential synthetic method. The dimension of both FePt and Fe3O4 was tuned by varying the synthesis parameters. The ...
  • Hard magnetic FePt nanoparticles by salt-matrix annealing 

    Li, Daren; Poudyal, Narayan; Nandwana, Vikas; Jin, Zhiqiang; Elkins, Kevin; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2006-04-26)
    To transfer face-centered-cubic (fcc) FePt nanoparticles to the face-centered-tetragonal (fct) phase with high magnetic anisotropy, heat treatments are necessary. The heat treatments lead to agglomeration and sintering of ...
  • Temperature- and magnetic-field-induced phase transitions in Fe-rich FePt alloys 

    Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-06-01)
    Structural and magnetic properties of the FexPt100-x (x=78–88) alloys have been investigated. It is found that for all of the investigated compositions, a phase transition occurs from the disordered γ phase to the ordered ...
  • Shape control of FePt nanocrystals 

    Poudyal, Narayan; Chaubey, Girija Shankar; Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-04-06)
    : FePt nanocrystals were prepared by simultaneous reduction of platinum acetylacetonate and thermal decomposition of iron pentacarbonyl in properly chosen solvents/surfactants. A variety of FePt nanocrystals, including ...
  • Mechanism of the anomalous temperature dependence of coercivity in Sm(Co,Fe,Cu,Zr)[subscript]z high-temperature magnets 

    Rong, Chuanbing; Zhang, Hong-wei; Shen, Bao-gen; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2006-01-24)
    Coercivity mechanism of the precipitation-hardened Sm(Co,Fe,Cu,Zr)z high-temperature magnets was found to vary with temperature by measurements of reversible magnetization. The magnetization reversal is mainly controlled ...
  • Bulk FePt-based nanocomposite magnets with enhanced exchange coupling 

    Rong, Chuanbing; Nandwana, Vikas; Poudyal, Narayan; Liu, J. Ping; Kozlov, Mikhail E.; Baughman, Ray H.; Ding, Yong; Wang, Zhong Lin (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-07-23)
    High density bulk FePt/Fe3Pt nanocomposite magnets have been prepared by high-pressure warm compaction of chemically synthesized FePt and Fe3O4 nanoparticles. It is found that the density increases with the compaction ...
  • Curie temperatures of annealed FePt nanoparticle systems 

    Rong, Chuanbing; Li, Yang; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-03-28)
    The chemically synthesized FexPt100-x nanoparticles with controlled compositions were annealed to transfer the disordered face-centered-cubic structure to the ordered structure. It was found that the L10 FePt structure can ...
  • Grain boundary contribution to recoil loop openness of exchange-coupled nanocrystalline magnets 

    Rong, Chuanbing; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2009-04-29)
    It has been well known that recoil loop openness is related to soft-phase presence in exchange-coupled hard-soft nanocomposite magnets. Our study on recoil loop openness of exchange-coupled nanocrystalline magnets (both ...
  • Structural phase transition and ferromagnetism in monodisperse 3 nm FePt particles 

    Rong, Chuanbing; Poudyal, Narayan; Chaubey, Girija Shankar; Nandwana, Vikas; Skomski, R.; Wu, Y.Q.; Kramer, Matthew J.; Liu, J. Ping (American Institute of PhysicsDepartment of Physics, The University of Texas at Arlington, 2007-08-30)
    FePt nanoparticles with a size of 3 nm and thermally stable room-temperature ferromagnetism are investigated. The monodisperse nanoparticles were prepared by chemical synthesis and a salt-matrix annealing technique. ...

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